Co-reporter:Chao Liu, Ruirui Han, Hongmei Ji, Tao Sun, Jin Zhao, Ningna Chen, Jing Chen, Xuefeng Guo, Wenhua Hou and Weiping Ding
Physical Chemistry Chemical Physics 2016 vol. 18(Issue 2) pp:801-810
Publication Date(Web):23 Nov 2015
DOI:10.1039/C5CP06555K
The S-doped mesoporous nanocomposite (S-TNT) of HTiNbO5 nanosheets (NSs) and anatase TiO2 nanoparticles (NPs) with exposed {101} facets has been successfully synthesized by first mixing freeze-dried HTiNbO5 NSs with titanium isopropoxide and then calcination with thiourea in air. The exposed anatase {101} facets can act as a possible reservoir of the photogenerated electrons, yielding a highly reactive surface for the reduction of O2 to O2˙−. The partial substitution of Ti4+ by S6+ in the lattice of TiO2 NPs leads to a charge imbalance in S-TNT and the formation of Ti–O–S bonds. As a result, the formed cationic S-TNT favours adsorption of hydroxide ions (OH−ads) and thus captures the photo-induced holes to form hydroxyl radicals (˙OH). Moreover, with the formation of Ti–O–S bonds, partial electrons can be transferred from S to O atoms and hence the electron-deficient S atoms might capture photo-induced electrons. The surface-adsorbed SO42− could also act as an efficient electron trapping center to promote the separation of charge carriers. In addition, the Ti3+ species due to the removal of oxygen atoms during calcination and the associated oxygen vacancy defects on the surface of S-TNT could act as hole and electron scavengers, respectively. Besides, the closely contacted interface is formed between HTiNbO5 NSs and anatase TiO2 NPs due to the common features of TiO6 octahedra in two components, resulting in a nanoscale heterojunction structure to speed up the separation rate of photogenerated charge carriers. The formation of a nano-heterojunction and the incorporation of Ti3+ and S dopants give rise to the visible and near-infrared light response of S-TNT. The combined effects greatly retard the charge recombination and improve the photocatalytic activity for the degradation of rhodamine B (RhB) and phenol solution under visible light irradiation. The corresponding photocatalytic mechanism was investigated via the active species capture experiments. The present work may provide an insight into the fabrication of delicate composite photocatalysts with excellent performance.
Co-reporter:Jian Chen, Weigang Mei, Qianjin Huang, Ningna Chen, Chunliang Lu, Hongjun Zhu, Jing Chen, Wenhua Hou
Journal of Alloys and Compounds 2016 Volume 688(Part B) pp:225-234
Publication Date(Web):15 December 2016
DOI:10.1016/j.jallcom.2016.07.196
•3D flower-like AgI/Bi2O2CO3 photocatalyst was fabricated via a simple two-step method.•Heterojunction photocatalyst exhibited an enhanced activity and reusability.•Staggered gap structure enhanced the separation of photo-induced electrons and holes.Novel AgI/Bi2O2CO3 composites, in which AgI nanoparticles were highly dispersed on Bi2O2CO3 nanosheets, acting as building blocks for the assembly of three-dimensional flower-like microspheres, were prepared by a simple in situ deposition process. The as-prepared samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, N2 adsorption–desorption isotherms, X-ray photoelectron spectroscopy and UV–visible diffuse reflectance spectroscopy. The photocatalytic activity was investigated for the degradation of RhB under visible light irradiation. The results showed that the as-prepared AgI/Bi2O2CO3 heterojunctions exhibited a much higher activity than pure Bi2O2CO3 and AgI. When the amount of AgI was controlled at 25% (molar ratio), the highest photocatalytic performance could be achieved. The photoluminescence (PL) spectra indicated that the recombination of photogenerated electron–hole pairs was suppressed effectively due to the formation of heterojunction between AgI nanoparticles and Bi2O2CO3 nanosheets. Trapping experiments indicated that h+ and ⋅O2− radicals were the main reactive species responsible for the degradation of RhB in the photocatalytic system. Furthermore, the good stability of AgI/Bi2O2CO3 composites was demonstrated by four successive photodegradations of RhB under visible light.
Co-reporter:Jian Chen, Weigang Mei, Chao Liu, Chenhui Hu, Qianjing Huang, Ningna Chen, Jing Chen, Rong Zhang, Wenhua Hou
Materials Letters 2016 Volume 172() pp:184-187
Publication Date(Web):1 June 2016
DOI:10.1016/j.matlet.2016.03.002
•Preparing a high specific surface BTO through acidification.•Ethanol as carbon source, obtained carbon modified BTO with a large surface area.•The prepared C/BTO has a good photocatalytic activity of degrading MO under nature sunlight.A novel carbon-modified bismuth titanate Bi4Ti3O12 (C/BTO) nanocomposites were successfully synthesized by a facile co-precipitation method. The resulted samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), X-ray photoelectron spectroscopic (XPS), N2 adsorption–desorption and UV–vis diffuse reflectance spectroscopy (UV–vis DRS). The photocatalytic activities of the samples were measured through the photocatalytic degradation of methyl orange (MO) aqueous solution under sunlight. Compared with commercial P25, the resulted C/BTO showed an excellent photocatalytic activity. The mechanism for the improved photocatalytic activity was finally proposed.
Co-reporter:Hongmei Ji;Xiaolin Liu;Zhijuan Liu;Bo Yan;Lin Chen;Yafeng Xie;Chao Liu;Wenhua Hou;Gang Yang
Advanced Functional Materials 2015 Volume 25( Issue 12) pp:1886-1894
Publication Date(Web):
DOI:10.1002/adfm.201404378
This work presents a design of sandwich MoO3/C hybrid nanostructure via calcination of the dodecylamine-intercalated layered α-MoO3, leading to the in situ production of the interlayered graphene layer. The sample with a high degree of graphitization of graphene layer and more interlayered void region exhibits the most outstanding energy storage performance. The obtained material is capable of delivering a high specific capacitance of 331 F g−1 at a current density of 1 A g−1 and retained 71% capacitance at 10 A g−1. In addition, nearly no discharge capacity decay between 1000 and 10 000 continuous charge–discharge cycles is observed at a high current density of 10 A g−1, indicating an excellent specific capacitance retention ability. The exceptional rate capability endows the electrode with a high energy density of 41.2 W h kg−1 and a high power density of 12.0 kW kg−1 simultaneously. The excellent performance is attributed to the sandwich hybrid nanostructure of MoO3/C with broad ion diffusion pathway, low charge-transfer resistance, and robust structure at high current density for long-time cycling. The present work provides an insight into the fabrication of novel electrode materials with both enhanced rate capability and cyclability for potential use in supercapacitor and other energy storage devices.
Co-reporter:Xiaolin Liu, Di Wu, Wenxu Ji and Wenhua Hou
Journal of Materials Chemistry A 2015 vol. 3(Issue 3) pp:968-972
Publication Date(Web):24 Nov 2014
DOI:10.1039/C4TA04373A
Uniform MoO2@C hollow nanospheres were facilely synthesized through a soft-templated hydrothermal method. This approach effectively integrates material fabrication and carbon coating into one step. Due to their unique structure characteristics, the resulting MoO2@C hollow nanospheres exhibited superior lithium-ion storage properties.
Co-reporter:Chao Liu, Ji-yuan Liang, Rui-rui Han, Yong-zheng Wang, Jin Zhao, Qian-jin Huang, Jing Chen and Wen-hua Hou
Physical Chemistry Chemical Physics 2015 vol. 17(Issue 23) pp:15165-15172
Publication Date(Web):13 May 2015
DOI:10.1039/C5CP01552A
S-doped Na2Ti6O13@TiO2 (S-TTO) core–shell nanorods, with exposed anatase TiO2 {101} facets, were synthesized by a facile calcination method. It was found that the addition of thiourea as the sulfur precursor was beneficial for the formation of anatase TiO2 with a better crystallinity and the doped sulfur atoms favorably stabilized the anatase structure. The substitution of Ti4+ by S6+ in the lattice of S-TTO gave rise to the visible light response and increased the amount of active groups typically as a hydroxyl radical adsorbed onto the catalyst surface. With the formation of the Ti–O–S bond, partial electrons could be transferred from S to O atoms. The electron-deficient S atoms might capture e− and thus inhibit the recombination of photogenerated electron–hole pairs. Meanwhile, a closely contacted interface was formed between Na2Ti6O13 and anatase TiO2, resulting in a nanoscale heterojunction structure to speed up the separation rate of photogenerated charge carriers. The exposed anatase {101} facets could act as possible reservoirs of the photogenerated electrons, yielding a highly reactive surface for the reduction of O2 to O2˙− and thus the decrease of recombination probability of electron–hole pairs. In addition, the anisotropically shaped titanate nanorods provided a pathway for the quick transport of charge carriers throughout the longitudinal direction. The combined effects of S doping, nano-heterojunction formation and morphology engineering led to an obviously enhanced photocatalytic performance for the degradation of methylene blue (MB) solution under visible light irradiation. The corresponding photocatalytic mechanism was investigated and discussed in detail. The present work may provide an insight into the fabrication of delicate composite photocatalysts with excellent performance.
Co-reporter:Lihong Zhang, Chenhui Hu, Weigang Mei, Junfeng Zhang, Liyuan Cheng, Nianhua Xue, Weiping Ding, Jing Chen, Wenhua Hou
Applied Surface Science 2015 Volume 357(Part B) pp:1951-1957
Publication Date(Web):1 December 2015
DOI:10.1016/j.apsusc.2015.09.157
Highlights
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Sulfated Zr-doped titanoniobate nanoplates were successfully prepared.
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The resulted catalyst exhibited a remarkable catalytic activity in the alcoholysis of styrene epoxide at room temperature.
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The resulted catalyst also showed an excellent reusability.
Co-reporter:Chao Liu, Liang Wu, Jing Chen, Ji-yuan Liang, Chang-shun Li, Hong-mei Ji and Wen-hua Hou
Physical Chemistry Chemical Physics 2014 vol. 16(Issue 26) pp:13409-13417
Publication Date(Web):16 May 2014
DOI:10.1039/C4CP01423E
An effective approach has been used to synthesize N-doped HTiNbO5 (denoted as N-HTiNbO5) with a better intercalation property. The synthesis of polyaniline (PANI) with N-HTiNbO5 to form PANI–N-HTiNbO5 lamellar nanocomposites by in situ polymerization using the aniline (ANI) intercalation compound ANI/N-HTiNbO5 as the intermediate has been investigated. The resulting PANI–N-HTiNbO5 nanocomposite showed a better crystallinity with a monolayer of PANI within the interlayers of N-HTiNbO5, because nitrogen doping can affect the surface charge distribution of [TiNbO5]− layers. The cyclic voltammetry (CV) results indicated that the PANI–N-HTiNbO5 nanocomposite had good redox activity and electrochemical-cycling stability in acidic solution. The visible-light response of the PANI–N-HTiNbO5 nanocomposite was enhanced through N-doping, acid exchange, and the intercalation of PANI. The PANI–N-HTiNbO5 nanocomposite showed the highest activity with 97.8% methylene blue (MB) photodegraded in 170 min under visible light irradiation. The significant enhancement of photocatalytic performance can be attributed to the high efficiency of charge separation, induced by the synergistic effect between PANI and N-HTiNbO5. In addition, the PANI–N-HTiNbO5 nanocomposite had a high thermal and photodegradation stability due to the intercalation reaction at the molecular level.
Co-reporter:Xiaolin Liu, Wenxu Ji, Jiyuan Liang, Luming Peng and Wenhua Hou
Physical Chemistry Chemical Physics 2014 vol. 16(Issue 38) pp:20570-20577
Publication Date(Web):12 Aug 2014
DOI:10.1039/C4CP02960G
MoO2 hollow microspheres with tunable inner space have been synthesized through a hydrothermal process using MoO3 microbelts instead of bulk MoO3 as the precursor. It is found that the reactant morphology has a great impact on the product morphology and the inner space can be tuned by changing the amount of NaOH aqueous solution. An interesting evolutional process from MoO3 microbelts through a rose-like intermediate to MoO2 hollow microspheres has been clearly observed, and thus the possible formation mechanism is revealed. One layer of amorphous carbon has been subsequently coated on the surface of MoO2 hollow microspheres through a simple hydrothermal approach followed by annealing in argon. As the anode material for lithium ion batteries, MoO2@C hollow microspheres manifest excellent lithium-storage properties, such as high capacity (677 mA h g−1) and good cycling stability (negligible capacity fading even after 80 cycles). The significantly enhanced performance of MoO2@C hollow microspheres can be attributed to its unique structures, such as nanoscaled primary building blocks, carbon coating, hollow structure, and especially the synergy between the carbon coating and hollow structure.
Co-reporter:Xiaolin Liu, Wenhua Hou, Xiaoyan Yang and Jiyuan Liang
CrystEngComm 2014 vol. 16(Issue 7) pp:1268-1276
Publication Date(Web):19 Nov 2013
DOI:10.1039/C3CE41712C
Uniform single-crystalline NaLa(WO4)2 microspindles were successfully prepared via a hydrothermal method in combination with a post annealing process by adding an extremely small amount of EDTA-2Na into the reaction system. Meanwhile, the product morphology could also be tuned into microplates, nanocrystals, submicrodumbbells and connected twin-microspheres by simply altering the amount of additive used and the ratio of the mixed solvents. The prepared NaLa(WO4)2 nanocrystals could be homogeneously dispersed in the distilled water for a very long time, and thus might find potential application in the field of biological labeling. The photoluminescent (PL) performance of the NaLa(WO4)2: Eu3+ microspindles and microplates was investigated and it was found that the NaLa(WO4)2: Eu3+ microspindles had a much more intensive emission, and furthermore, the possible reasons responsible for the improved photoluminescent performance of the microspindles were discussed. More importantly, due to the efficient energy transfer from Tm3+, Tb3+ to Eu3+, a novel single-phased and near-UV-pumped white-light-emitting phosphor NaLa(WO4)2: Eu3+/Tb3+/Tm3+ was also successfully fabricated through optimizing the molar ratio among Eu3+, Tb3+ and Tm3+ in the NaLa(WO4)2 microspindle host. This NaLa(WO4)2: Eu3+/Tb3+/Tm3+ microspindle phosphor might be promising in the field of near-UV-pumped white LEDs.
Co-reporter:Lin Xu, Xiaoyan Yang, Haimeng Lu, Chenhui Hu and Wenhua Hou
RSC Advances 2014 vol. 4(Issue 26) pp:13502-13508
Publication Date(Web):04 Mar 2014
DOI:10.1039/C4RA00244J
We present a facile synthesis of NaY(MoO4)2 microcrystals with controlled morphologies and tunable faceting via an ethylenediaminetetraacetic acid (EDTA)-mediated hydrothermal method. Three different types of NaY(MoO4)2 microcrystals, namely, sharp bipyramids, truncated bipyramids, and quasi-cubes, can be selectively produced, and the percentage of {001} and {101} facets in the tetragonal bipyramidal NaY(MoO4)2 microcrystals can be engineered through the judicious choice of an appropriate amount of EDTA. The preferential adsorption of EDTA on {001} facets of the NaY(MoO4)2 crystal is responsible for the morphology evolution of the NaY(MoO4)2 microcrystals from sharp bipyramids to quasi-cubes. The present synthetic approach is also extendable to achieve NaHo(MoO4)2 and NaTb(MoO4)2 microcrystals with different shapes and tunable exposed facets. It is found that the luminescence properties of the NaY(MoO4)2:Eu3+ microcrystals are highly dependent on their shape and size, and the sharp NaY(MoO4)2:Eu3+ bipyramids exhibit the strongest emission intensity due to their larger size, fewer defects and less exposed facets. As such, the sharp NaY(MoO4)2:Eu3+ bipyramids may have potential applications in light display systems as well as optoelectronic devices, while the present EDTA-mediated hydrothermal synthetic strategy represents a potentially general route to the generation of nano/microcrystals with shape- and exposed facet-control.
Co-reporter:Chenhui Hu, Lihong Zhang, Junfeng Zhang, Liyuan Cheng, Zheng Zhai, Jing Chen, Wenhua Hou
Applied Surface Science 2014 Volume 298() pp:116-124
Publication Date(Web):15 April 2014
DOI:10.1016/j.apsusc.2014.01.137
Abstract
Cu-containing nanotubes with a large surface area and pore volume were prepared by using nanoscrolls derived from K4Nb6O17 as a support and a subsequent thermal transformation of Cu-containing nanoscrolls into Nb2O5 nanotubes. The method is facile and template-free. The catalytic performance of the resulted Cu-containing nanotubes was evaluated for styrene epoxidation in the presence of tert-butyl hydroperoxide (TBHP) and H2O2, respectively. It was found that Cu-containing nanotubes displayed a relative good catalytic performance with a styrene oxide (SO) selectivity of 46.9% by TBHP and a much higher SO selectivity of 94.6% by H2O2. Two possible mechanisms were put forward to explain the different catalytic behaviors in the two types of oxidation systems. Because of the thermal transformation of nanoscrolls into nanotubes, nanoscrolls may be a new kind of promising support for the design and assembly of novel heterogeneous catalysts.
Co-reporter:Xiaomiao Feng, Yu Zhang, Zhenzhen Yan, Ningna Chen, Yanwen Ma, Xingfen Liu, Xiaoyan Yang and Wenhua Hou
Journal of Materials Chemistry A 2013 vol. 1(Issue 34) pp:9775-9780
Publication Date(Web):14 Jun 2013
DOI:10.1039/C3TA11856H
Polyaniline (PANI) nanotubes with improved electrochemical activity were synthesized by using a self-degradable MnO2 template and were developed as electrode materials for biosensors. The morphology, composition, and optical properties of the resulting products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), and cyclic voltammetry (CV). The results confirmed that the obtained PANI nanotubes had a perfect tubular structure with uniform diameters and lengths. Furthermore, PANI nanotubes were immobilized onto the surface of a glassy carbon electrode (GCE) and applied to construct a sensor. The obtained PANI-modified GCE showed high catalytic activity in the electrochemical oxidation of dopamine (DA) in a near neutral environment. Differential pulse voltammogram (DPV) results illustrated that the fabricated DA biosensor had high anti-interference ability towards uric acid (UA), ascorbic acid (AA), and glucose (GC). In addition, the fabricated biosensor showed superior performance with two wide linear ranges from 7 × 10−5 to 3 × 10−4 M and 3 × 10−4 to 5 × 10−3 M with a lower limit of detection of 0.5 × 10−9 M.
Co-reporter:Lihong Zhang, Chenhui Hu, Junfeng Zhang, Liyuan Cheng, Zheng Zhai, Jing Chen, Weiping Ding and Wenhua Hou
Chemical Communications 2013 vol. 49(Issue 68) pp:7507-7509
Publication Date(Web):21 Jun 2013
DOI:10.1039/C3CC42951B
Sulfur and iron co-doped titanoniobate nanosheets were prepared and evaluated in alcoholysis of styrene epoxide. The resultant co-doped catalyst exhibited excellent catalytic performance (yield of 99% with methanol as the nucleophile in only 1 h at room temperature) and may act as a promising candidate in many acid-catalyzed reactions.
Co-reporter:Xiaoyan Yang, Ye Zhang, Lin Xu, Zheng Zhai, Mingzhen Li, Meng Li, Xiaolin Liu and Wenhua Hou
Dalton Transactions 2013 vol. 42(Issue 11) pp:3986-3993
Publication Date(Web):11 Dec 2012
DOI:10.1039/C2DT32446F
For the first time, well-dispersed submicrometer-sized YVO4:Eu3+ hollow spheres were successfully synthesized though a surfactant-free method by employing Y(OH)CO3:Eu3+ colloidal spheres as a sacrificial template and NH4VO3 as a vanadium source. The synthetic process mainly consists of two steps, i.e., hydrothermal reaction and acid erosion. By simply changing the amount of NH4VO3 added, the textural parameters of the as-obtained hollow spheres, such as the inner diameter and shell-thickness, can be easily tuned. Moreover, double-shelled hollow spheres could also be obtained when the amount of NH4VO3 was increased to a certain extent. Particularly, the amorphous colloidal spheres of the template could be completely consumed when the amount of NH4VO3 was in large excess, giving rise to the direct formation of uniform hollow spheres without acid erosion. The possible formation process is discussed in detail. Under ultraviolet excitation, the obtained hollow YVO4:Eu3+ phosphors showed strong red emissions, and the Commission Internationale d'Eclairage (CIE) coordinates of the YVO4:Eu3+ phosphors were closely related with the textural parameters such as the inner diameter, shell-thickness and number of shells, indicating a size-dependent characteristic.
Co-reporter:Xiaolin Liu, Wenhua Hou, Xiaoyan Yang and Qingming Shen
Dalton Transactions 2013 vol. 42(Issue 32) pp:11445-11454
Publication Date(Web):30 May 2013
DOI:10.1039/C3DT50562F
The selective synthesis of pure-phase La2(WO4)3 nanocrystals and uniform spindle-like NaLa(WO4)2 nano/microcrystals with tunable size based on one reaction system has been reported for the first time. The sodium ion is crucial for the selective synthesis of La2(WO4)3 and NaLa(WO4)2. An additional hydrothermal treatment has a great effect on the morphology of La2(WO4)3, while the hydrothermal temperature and time, and the amount of glycerine, significantly influence the morphology and size of NaLa(WO4)2. Based on the time-dependent experiments, it is proposed that the Ostwald ripening is the formation mechanism of the spindle-like NaLa(WO4)2. The resultant La2(WO4)3:Er3+ nanocrystals can emit a bright red color with a high purity under the excitation of 467 nm (blue region) and, more importantly, it can be easily dispersed in distilled water. The up-conversion emission intensity of NaLa(WO4)2:Yb3+/Er3+ is increased rapidly with the Yb3+ concentration under 980 nm laser excitation, suggesting the efficient energy transfer from Yb3+ to Er3+. Moreover, the emission color can be tuned from chartreuse to green by increasing the Yb3+ concentration. These unique properties of La2(WO4)3 and NaLa(WO4)2 are closely related with their distinctive crystal structures, and it is anticipated that the findings in this work may give an insight into the fabrication and application of the rare earth tungstates.
Co-reporter:Xiaoyan Yang, Zheng Zhai, Lin Xu, Mingzhen Li, Ye Zhang and Wenhua Hou
RSC Advances 2013 vol. 3(Issue 12) pp:3907-3916
Publication Date(Web):21 Dec 2012
DOI:10.1039/C2RA22147K
Spiky ball- and triangular heart-like LaCO3OH microstructures were successfully prepared via a facile and mild hydrothermal route with the assistance of EDTA. The effect of reaction parameters such as chelators, reaction temperature and time on the product morphology was systematically investigated. It was found that the morphological modulation of the as-obtained products could be realized simply by changing reaction time. The possible formation mechanism for the stepwise self-assembly of spiky balls and triangular hearts was proposed on the basis of a series of time-dependent experiments. The adsorption properties of LaCO3OH spiky balls and triangular hearts for the removal of Rhodamine B (RhB) were evaluated. Due to the high specific surface area and complicated internal microstructure, the spiky balls exhibited a much higher adsorption rate and mass-specific adsorption capacity than bulk-shaped triangular hearts. However, a relatively higher area-specific adsorption capacity was found with bulk-shaped triangular hearts with a higher crystallinity. In addition, the adsorption kinetics of RhB by spiky balls follows the first-order reaction while that by triangular hearts zeroth-order, demonstrating the different adsorption behaviors of different microstructures.
Co-reporter:Xiaomiao Feng, Zhenzhen Yan, Ningna Chen, Yu Zhang, Xingfen Liu, Yanwen Ma, Xiaoyan Yang and Wenhua Hou
New Journal of Chemistry 2013 vol. 37(Issue 7) pp:2203-2209
Publication Date(Web):15 Apr 2013
DOI:10.1039/C3NJ00108C
A ternary nanocomposite of graphene/polyaniline (PANI)/porous silica MCM-41 (MCM-41) was prepared by a hydrothermal method. The amount of graphene oxide (GO) in the graphene/PANI/MCM-41 nanocomposite had a strong effect on the supercapacitor performance. The experimental results showed that the specific capacitance of the graphene/PANI/MCM-41 nanocomposite could reach the highest value when the GO content was 50%. The specific capacitance of the nanocomposite was 405 F g−1 at a current density of 0.8 A g−1. Furthermore, over 91.4% of the original capacitance was retained after repeating the galvanostatic charge–discharge for 1000 cycles. The performance of the prepared supercapacitor containing different amounts of GO were studied in detail.
Co-reporter:Xiaomiao Feng;Zhenzhen Yan;Ruimei Li;Xingfen Liu;Wenhua Hou
Polymer Bulletin 2013 Volume 70( Issue 8) pp:2291-2304
Publication Date(Web):2013 August
DOI:10.1007/s00289-013-0952-x
Polypyrrole (PPy)/graphene nainocomposite was prepared by methyl orange (MO) reactive template. By changing the amount of MO, the morphology of PPy can be controlled to range from nanoparticle to nanowire. Transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction results demonstrated that the composites were successfully synthesized. The different morphologies of PPy/graphene nanocomposites had certain effects on the supercapacitor performance. The experimental results showed that the capacitance of PPy (nanoparticle)/graphene was higher than that of PPy (nanowire)/graphene. As a model, PPy (nanoparticle)/graphene was used to construct a supercapacitor. By changing the amount of pyrrole monomer, the performance of the supercapacitor prepared from different PPy content was studied in detail.
Co-reporter:Xiaoyan Yang, Lin Xu, Zheng Zhai, Fangfang Cheng, Zhenzhen Yan, Xiaomiao Feng, Junjie Zhu, and Wenhua Hou
Langmuir 2013 Volume 29(Issue 51) pp:15992-16001
Publication Date(Web):December 5, 2013
DOI:10.1021/la403476f
Hollow spheres of heavy lanthanide orthovanadates (LnVO4, Ln = Tb, Dy, Er, Tm, Yb, Lu) and yolk–shell structures of Ho(OH)CO3@HoVO4 have been successfully prepared by employing Ln(OH)CO3 colloidal spheres as a sacrificial template and NH4VO3 as a vanadium source. In particular, the as-obtained LuVO4 hollow spheres are assembled from numerous hollow-structured elliptic nanoparticles, and their textural parameters such as the inner and outer diameters, shell thicknesses, and number of shells could be finely tuned through introducing different amounts of NH4VO3 and employing Lu(OH)CO3 templates with different sizes. The possible mechanisms for the formation of hollow spheres and yolk–shell structures, and also the hollow-structured elliptic nanoparticles of LuVO4, i.e., building blocks of LuVO4 hollow spheres, are proposed and discussed in detail. Under ultraviolet excitation, the obtained LuVO4:Eu3+ hollow spheres show strong red emissions located in the saturated color region, and the modulation of emission intensity and color purity could be realized by tuning the textural parameters of the obtained hollow spheres. It was found that the nanostructure of the building blocks of LuVO4:Eu3+ hollow spheres also had an effect on the luminescent properties of the as-obtained materials. Moreover, the quantum efficiency could be affected by the textural parameters of the as-obtained LuVO4:Eu3+ hollow spheres, and the double-shelled LuVO4:Eu3+ hollow sphere has the highest quantum efficiency. In addition, the excellent biocompatibility indicates the potential biological applications of LuVO4 hollow spheres.
Co-reporter:Zheng Zhai, Chenhui Hu, Xiaoyan Yang, Lihong Zhang, Chao Liu, Yining Fan and Wenhua Hou
Journal of Materials Chemistry A 2012 vol. 22(Issue 36) pp:19122-19131
Publication Date(Web):16 Jul 2012
DOI:10.1039/C2JM32338A
Nitrogen-doped mesoporous nanohybrids of TiO2 nanoparticles and HTiNbO5 nanosheets have been successfully synthesized by first exfoliating layered HTiNbO5 in tetrabutylammonium hydroxide (TBAOH) to obtain HTiNbO5 nanosheets, then reassembling with TiO2 colloids and finally heating with urea in air at 450 °C. The resulting samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), X-ray photoelectron spectroscopy (XPS), UV-vis spectroscopy, laser Raman spectroscopy (LRS) and N2 adsorption–desorption measurements. It was found that the TiO2 nanoparticles existed in the anatase phase and the titanoniobate nanosheets were still maintained after nitrogen doping. The obtained nitrogen-doped nanohybrids showed a greatly expanded surface area with a mesoporous structure and the doped nitrogen atoms were located in the interstitial sites of TiO2, giving rise to the visible light response. The catalytic activities of the obtained samples were evaluated by the photodegradation of rhodamine B (RhB) solution under visible light irradiation. The obtained N-doped nanohybrid had a higher activity than N-doped HTiNbO5 nanosheets and N-doped TiO2, indicating the synergetic effect of TiO2 nanoparticles and HTiNbO5 nanosheets. The dye molecules were mainly degraded to aliphatic organic compounds and mostly further mineralized to CO2 and/or CO, rather than being simply decolorized. In addition, the cell viability results of the HepG2 cells showed that the as-prepared sample had a good biocompatibility.
Co-reporter:Zheng Zhai, Xiaoyan Yang, Lin Xu, Chenhui Hu, Lihong Zhang, Wenhua Hou and Yining Fan
Nanoscale 2012 vol. 4(Issue 2) pp:547-556
Publication Date(Web):30 Nov 2011
DOI:10.1039/C1NR11091H
Mesoporous nanohybrids of NiO nanoparticles and HTiNbO5 nanosheets have been successfully synthesized by first exfoliating layered HTiNbO5 in tetrabutylammonium hydroxide (TBAOH) to obtain HTiNbO5 nanosheets, then reassembling with a nickel precursor and finally heating with urea. The resulting samples were characterized by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), UV-vis spectroscopy, photoluminescence spectroscopy (PL) and N2 adsorption–desorption measurements. It was found that the as-prepared nanohybrids had a relatively large interlayer spacing of 1.05 nm. After calcination, the titanoniobate nanosheet was still retained and the pore size of the resulting nanohybrids became larger. Compared with the original HTiNbO5, the obtained nanohybrids were mesoporous with a greatly expanded surface area (∼75–115 m2 g−1), a much strengthened absorption in the UV light region and a visible-light response. Nickel atoms were present in the form of Ni–O in the nanohybrid, and NiO nanoparticles were homogeneously distributed with an average particle size of 2–3 nm, giving rise to the visible light response. The catalytic activities of the obtained samples were evaluated by the photodegradation of RhB solution under visible light irradiation. The introduction of urea during the calcination process not only increased the thermal stability and surface area, but also decreased the rate of recombination of photogenerated holes and electrons, leading to a greatly enhanced photocatalytic activity of the resulting nanohybrids. The dye molecules were mainly degraded to aliphatic organic compounds and partially mineralized to CO2 and/or CO, rather than being simply decolorized. In addition, cell viability results for HepG2 cells show that the as-prepared sample have good biocompatibility.
Co-reporter:Lin Xu, Xiaoyan Yang, Zheng Zhai, Daxian Gu, Huan Pang and Wenhua Hou
CrystEngComm 2012 vol. 14(Issue 21) pp:7330-7337
Publication Date(Web):02 Aug 2012
DOI:10.1039/C2CE25897H
In this paper, various NaCe(MoO4)2 3D hierarchical architectures self-assembled from different building blocks were successfully synthesized by a facile EDTA-mediated hydrothermal method for the first time. X-Ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) and N2 adsorption were employed to characterize the as-obtained products. Three important parameters, the amount of EDTA, pH value of the precursor solution and the molybdate resource were found to be important in determining the building blocks and their spacial arrangement in the final products. A plausible formation mechanism for the NaCe(MoO4)2 microflowers was proposed based on time-dependent experiments. As enlightened by the intrinsic property and fascinating hierarchical structures of NaCe(MoO4)2, a potential application of NaCe(MoO4)2 as an adsorbent in water treatment was also investigated for the first time. NaCe(MoO4)2 microflowers with bimodal pores exhibited a favorable adsorption performance for the removal of Rhodamine B (RhB), displaying a potential application in environmental remediation.
Co-reporter:Qingming Shen, Qianhao Min, Jianjun Shi, Liping Jiang, Wenhua Hou, Jun-Jie Zhu
Ultrasonics Sonochemistry 2011 Volume 18(Issue 1) pp:231-237
Publication Date(Web):January 2011
DOI:10.1016/j.ultsonch.2010.05.011
In this paper, stabilizer-free gold nanoparticles (Au NPs) were synthesized by a facile pulse sonoelectrochemical method in the absence of stabilizer. The size and shape of the Au NPs can be controlled by adjusting current density, reaction time and the pH value of the precursor solution. The morphology and structure of the Au NPs were characterized by transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), UV–visable spectra (UV–vis), energy-dispersive X-ray (EDX) and X-ray diffraction (XRD). The pH value has a great effect on the size and dispersion of the obtained Au NPs. The Au NPs could further used as substrate for fabrication of HRP biosensor which exhibited excellent biocatalytical activity with high sensitivity and rapid response. This method provides a facile route for the synthesis of stabilizer-free Au NPs. Since the preparation process do not need the addition of any surfactants/capping agent, the resulting Au NPs are suitable for the applications in fields of biology and catalysis.
Co-reporter:Lin Xu, Xiaoyan Yang, Zheng Zhai, Xing Chao, Zihui Zhang and Wenhua Hou
CrystEngComm 2011 vol. 13(Issue 15) pp:4921-4929
Publication Date(Web):09 Jun 2011
DOI:10.1039/C1CE05181D
Tetragonal NaEu(MoO4)2 with rugby-like microstructures were successfully synthesized by a hydrothermal method in an EDTA-mediated process. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM) techniques were employed to characterize the products in detail. It was found that the amount of EDTA, reaction temperature and pH value are important parameters affecting the morphology, crystallinity and size of the final product, respectively. The possible formation mechanism for the microrugbies was proposed on the basis of a series of time-dependent experiments. This facile method was also successfully applied in the synthesis of NaSm(MoO4)2 and NaGd(MoO4)2 microrugbies. The photoluminescence (PL) properties of NaEu(MoO4)2 microrugbies were strongly dependent on the size and crystallinity. The calcined products displayed excellent luminescence behaviors with a high color purity and have the potential to be applied in LED devices. The possible reasons for the difference in the relative intensities of luminescence are also discussed in detail.
Co-reporter:Lin Xu, Xiaoyan Yang, Zheng Zhai and Wenhua Hou
CrystEngComm 2011 vol. 13(Issue 24) pp:7267-7275
Publication Date(Web):07 Oct 2011
DOI:10.1039/C1CE05671A
Bi2WO6 with multilayered disc-like and 3D hierarchical nest-like architectures self-assembled from 2D nanosheets were successfully synthesized by a hydrothermal method in EDTA-mediated processes. It was found that the morphology modulation of the as-obtained products could be easily realized simply by changing the amount of EDTA introduced into the reaction system. The stepwise self-assembly formation mechanisms for two different hierarchical architectures were proposed on the basis of a series of time-dependent experiments. The photocatalytic activities of the different Bi2WO6 samples for the degradation of Rhodamine B (RhB) were also evaluated. Due to the unique morphology, porous structure and large surface area, Bi2WO6 nest-like architectures exhibited better activity performance than Bi2WO6 multilayered microdiscs. The present work not only presents an efficient way for the selectively controllable preparation of Bi2WO6 hierarchical structures viaself-assembly from 2D nanosheets, but also provides a step forward in the design of photocatalysts with controllable morphology and enhanced photocatalytic activities.
Co-reporter:Xiaomiao Feng, Ruimei Li, Chenhui Hu, Wenhua Hou
Journal of Electroanalytical Chemistry 2011 Volume 657(1–2) pp:28-33
Publication Date(Web):1 July 2011
DOI:10.1016/j.jelechem.2011.03.004
A novel hemoglobin (Hb) electrode has been presented through adsorbing Hb onto graphene–Pt nanocomposite. The graphene–Pt with uniform sheet-like structure was obtained by microwave-assisted method. Positions of Soret absorption band showed Hb retained its natural configuration after adsorption onto graphene–Pt. The electrochemical behavior of the immobilized Hb was studied by cyclic voltammetry. The immobilized Hb showed a pair of stable and well-defined peaks at the formal potential of −0.26 V. As a model, a kind of novel third generation biosensor for H2O2 was developed. The resultant heme-protein electrode exhibited electrocatalytical responses to the reduction of H2O2, excellent stability, interference and good reproducibility. The presence of graphene enhanced the protein loadings, accelerates interfacial electron transfer and improves thermal stability of the adsorbed protein.Highlights► Graphene–Pt nanocomposite with uniform sheet-like structure was obtained by microwave-assisted method. ► Kind of novel third generation biosensor for H2O2 was developed through adsorbing Hb onto graphene–Pt nanocomposite. ► The biosensor exhibited electrocatalytical responses to the reduction of H2O2, excellent stability, interference and good reproducibility.
Co-reporter:Zheng Zhai;Yucheng Huang;Lin Xu;Xiaoyan Yang;Chenhui Hu;Lihong Zhang
Nano Research 2011 Volume 4( Issue 7) pp:
Publication Date(Web):2011 July
DOI:10.1007/s12274-011-0119-8
Nitrogen-doped HTiNbO5 nanosheets have been successfully synthesized by first exfoliating layered HTiNbO5 in tetrabutylammonium hydroxide (TBAOH) to obtain HTiNbO5 nanosheets and then heating the nanosheets with urea. The resulting samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Energy-dispersive X-ray (EDX), X-ray photoelectron spectroscopy (XPS), UV-vis spectroscopy and N2 adsorption-desorption measurements. It was found that N-doping resulted in a much higher thermostability of the layered structure, intrinsic bandgap narrowing and a visible light response. The doped nitrogen atoms were mainly located in the interstitial sites of TiNbO5− lamellae and chemically bound to hydrogen ions. Compared with N-doped HTiNbO5, N-doped HTiNbO5 nanosheets had a much larger specific surface area and richer mesoporosity due to the rather loose and irregular arrangement of titanoniobate nanosheets. Both N-doped layered HTiNbO5 and HTiNbO5 nanosheets showed a very high visible-light photocatalytic activity for the degradation of rhodamine B (RhB) aqueous solution. Moreover, due to the considerably larger surface area, richer mesoporosity and stronger acidity, N-doped HTiNbO5 nanosheets had an even higher activity than N-doped HTiNbO5, although the latter had a stronger absorption in the visible region. The dye molecules were mainly degraded to aliphatic organic compounds and partially mineralized to CO2 and/or CO, rather than being simply decolorized. The effect of photosensitization was insignificant and RhB was degraded mainly via the typical photocatalytic reaction routes. Two different reaction routes for the photodegradation of RhB under visible light irradiation over N-doped HTiNbO5 nanosheets have been proposed. The present method can be extended to a large number of layered metal oxides that have the characteristics of intercalation and exfoliation, thus providing new opportunities for the fabrication of highly effective and potentially practical visible-light photocatalysts.
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Co-reporter:Qingming Shen ; Xiaomei Zhao ; Shiwei Zhou ; Wenhua Hou ;Jun-Jie Zhu
The Journal of Physical Chemistry C 2011 Volume 115(Issue 36) pp:17958-17964
Publication Date(Web):August 3, 2011
DOI:10.1021/jp203868t
ZnO/CdS hierarchical nanospheres were prepared for photoelectrochemical selective sensing of Cu2+. Hierarchical ZnO nanospheres were first synthesized by the hydrolysis of zinc salt under ultrasound irradiation, and then CdS nanocrystals were selectively grown on the hierarchical ZnO nanospheres. The light scattering of ZnO nanospheres and the heterointerfaces between CdS and ZnO provided significant advantages for enhanced light absorption and charge separation, thus resulting in an improvement in the photocurrent intensity. A photoelectrochemical sensor was developed based on the interaction between Cu2+ and CdS. The results showed that this sensor has a good selectivity and high sensitivity for Cu2+ detection.
Co-reporter:Lin Xu, Chunliang Lu, Zihui Zhang, Xiaoyan Yang and Wenhua Hou
Nanoscale 2010 vol. 2(Issue 6) pp:995-1005
Publication Date(Web):06 May 2010
DOI:10.1039/B9NR00392D
Tetragonal La2(MoO4)3 with various novel and complex 3D hierarchical architectures self-assembled from different building blocks were successfully synthesized by a hydrothermal method in EDTA-mediated processes. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM) were employed to characterize the as-obtained products. It was found that morphology modulation could be easily realized simply by changing the amount of EDTA introduced into the reaction system. The amount of EDTA not only affected the substructures of the hierarchical structures, but also determined the size distributions of the final products. The formation mechanisms for different hierarchical architectures were proposed on the basis of a series of time-dependent experiments. An investigation on the photoluminescence (PL) properties of La2(MoO4)3:Eu with different morphologies revealed that the optical properties were strongly correlated with the morphology and size. Furthermore, as highlighted by the fascinating hierarchical structures of La2(MoO4)3, the potential application of La2(MoO4)3 as an absorbent in water treatment was also investigated for the first time. Possible reasons responsible for the differences in photoluminescence behaviors and absorption activities of different hierarchical architectures were discussed.
Co-reporter:Yuping Chen, Gang Yang, Zihui Zhang, Xiaoyan Yang, Wenhua Hou and Jun-Jie Zhu
Nanoscale 2010 vol. 2(Issue 10) pp:2131-2138
Publication Date(Web):08 Sep 2010
DOI:10.1039/C0NR00246A
Polyaniline-intercalated layered vanadium oxide nanocomposites were successfully synthesized by an one-pot hydrothermal method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), Fourier transform infrared spectroscopy (FT-IR), and Raman spectroscopy. The effects of reaction conditions, such as pH value of the precursor solution, reaction temperature and time, and the amount of aniline on the structure and morphology of the obtained samples, were systematically investigated. Based on the experimental results, an in situ intercalation-polymerization-exfoliation mechanism was put forward for the formation of layered nanocomposites. The application of the resulting layered nanocomposite as the cathode material in lithium battery was tested and the results showed that the polyaniline-intercalated layered vanadium oxide nanocomposite prepared at 140 °C had a good cycling performance and might act as a promising cathode material for high-energy-density rechargeable lithium batteries.
Co-reporter:Yuping Chen, Chunliang Lu, Lin Xu, Ying Ma, Wenhua Hou and Jun-Jie Zhu
CrystEngComm 2010 vol. 12(Issue 11) pp:3740-3747
Publication Date(Web):12 Jul 2010
DOI:10.1039/C000744G
Single crystalline MoO3 nanobelts with width of 200–300 nm and the length up to several tens of micrometres were prepared by a facile hydrothermal method and characterized. Based on time- and temperature-dependent experiments, a solid–solution–solid transformation mechanism was proposed for the formation of crystalline MoO3 nanobelts. The as-prepared MoO3 nanobelts were used as a photocatalyst to degrade methylene blue (MB) under visible light irradiation and demonstrated a dramatic activity, indicating that the as-prepared MoO3 nanobelts were promising candidates for the photodegradation of organic dyes. A self-sensitization photocatalytic mechanism was suggested based on the experimental results.
Co-reporter:Chunliang Lu, Qingming Shen, Xiaomei Zhao, Junjie Zhu, Xuefeng Guo, Wenhua Hou
Sensors and Actuators B: Chemical 2010 Volume 150(Issue 1) pp:200-205
Publication Date(Web):21 September 2010
DOI:10.1016/j.snb.2010.07.016
Co-reporter:Lin Xu, Jianmin Shen, Chunliang Lu, Yuping Chen and Wenhua Hou
Crystal Growth & Design 2009 Volume 9(Issue 7) pp:3129
Publication Date(Web):May 12, 2009
DOI:10.1021/cg801068k
Monoclinic Y2(WO4)3:Eu with three-dimensional hierarchical architectures were successfully synthesized by a hydrothermal method in ligand-free and chelating ligand-mediated processes, respectively. Microflowers assembled from two-dimensional nanoflakes were obtained in a surfactant- and template-free process, whereas microspheres with dandelion-like appearance assembled from one-dimensional nanoplates were observed upon the introduction of the appropriate amount of ethylenediamine tetraacetic acid (EDTA) to the precursor. X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected-area electron diffraction (SAED), energy-dispersive spectra (EDS), and photoluminescence (PL) spectroscopy were employed to characterize the as-obtained products. It was found that the amount of ligand agent, reaction temperature and time, and type of organic additive have crucial influences on the morphology of the resulting microstructures. The possible formation mechanisms for different microstructures were put forward. The addition of EDTA significantly changed the reaction pathway due to the excellent chelating and capping ability of EDTA. A detailed investigation on the photoluminescence of Y2(WO4)3:Eu samples with flower-like, dandelion-like, and spindle microstructures indicates that the optical properties of these phosphors are strongly dependent on the morphology and size. The dandelion-like structure exhibits the strongest red emission with high color purity.
Co-reporter:Lin Xu, Chunliang Lu, Jianmin Shen, Yuping Chen, Zihui Zhang and Wenhua Hou
CrystEngComm 2009 vol. 11(Issue 7) pp:1323-1330
Publication Date(Web):11 Mar 2009
DOI:10.1039/B820335K
Monoclinic YW2O6(OH)3:Eu with 3D hierarchical superstructures, namely, micro-waxberry and micro-flower, have been selectively synthesized via an efficient surfactant- and template-free hydrothermal process for the first time. Morphology modulation can be easily realized simply by changing the pH value of the precursor medium. X-Ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution TEM (HRTEM), energy-dispersive X-ray (EDX) spectrometry and photoluminescence (PL) spectra were employed to characterize the as-obtained products. A possible formation mechanism of the YW2O6(OH)3:Eu hierarchical architectures was proposed on the basis of time-dependent experiments. Comparative experiments indicated that pure and well-crystallized YW2O6(OH)3:Eu could be obtained only in an appropriate pH range of 2–3. An investigation on the PL properties of two YW2O6(OH)3:Eu samples with waxberry-like and flower-like microstructures revealed that the optical properties were strongly correlated with the crystallinity and morphology. Both samples exhibited red emissions with a high color purity. More importantly, micro-waxberry displayed a stronger emission and possessed a much higher R/O value than micro-flower, implying an improvement of color purity. Through fine adjustment of the pH value of the initial solution from 3 to 2, not only was better crystallinity obtained, but also the enhanced red color purity could be realized. The possible reasons responsible for this improvement were discussed.
Co-reporter:Gang Yang;Yuge Liu;Wenhua Hou;Hongmei Ji;Yuhong Li
Journal of Applied Polymer Science 2009 Volume 113( Issue 1) pp:78-86
Publication Date(Web):
DOI:10.1002/app.29907
Abstract
Aniline monomers could be easily inserted into and polymerized within the interlayers of HNb3O8. The conformation and electrochemical properties of the resulting nanocomoposites were discussed in detail. Two different mechanisms were proposed for the polymerization of monomers within the confined interlayers initiated by chemical oxidants and microwave irradiation, respectively. The analyses of thermogravimetric/differential scanning calorimetric analyses, X-ray diffraction, and Fourier transform infrared spectra indicated that the aromatic rings of the interlayered polyaniline (PANI) could be parallel with or perpendicular to the inorganic slabs, and the interlayered PANI molecules were emeraldine salt and protonated by the protons of layered inorganic acid host. The cyclic voltammetry revealed that the properties of the layered host and the interlayer height have an effect on the redox behavior of the corresponding nanocomposites. Compared with the nanocomposites in which the aromatic rings were parallel with the inorganic slabs, the nanocomposites in which the aromatic rings were perpendicular to the slabs demonstrated a higher conductivity and electrochemical activity. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Co-reporter:Qingming Shen, Qianhao Min, Jianjun Shi, Liping Jiang, Jian-Rong Zhang, Wenhua Hou and Jun-Jie Zhu
The Journal of Physical Chemistry C 2009 Volume 113(Issue 4) pp:1267-1273
Publication Date(Web):2017-2-22
DOI:10.1021/jp807881s
A simple sonoelectrochemical method was used to realize the morphology-controlled synthesis of palladium nanostructures at room temperature. The palladium spherical nanoparticles, multitwinned particles, and spherical spongelike particles (SSPs) were successfully prepared in the presence of different surfactants or polymers. It was found that the size and shape of the Pd nanostructures could be controlled by varying current density and pH value of the precursor solution. The Pd nanostructures were characterized by transmission electron microscopy, high-resolution transmission electron microscopy, field emission scanning electron microscopy, energy-dispersive X-ray, and X-ray diffraction. The possible formation mechanism was discussed. In addition, the electrocatalytic properties of the Pd nanostructures for direct alcohol oxidation in alkaline media were systematically investigated. The results showed that SSPs had a higher electrochemical active surface and result in more stable and better electrocatalytic properties than other Pd nanostructures for the ethanol electro-oxidation.
Co-reporter:Jian-Min Shen, Lin Xu, Yu-Ge Liu, Chun-Liang Lu, Wen-Hua Hou and Jun-Jie Zhu
Chemistry of Materials 2008 Volume 20(Issue 9) pp:3034
Publication Date(Web):April 10, 2008
DOI:10.1021/cm702966x
In this paper, bunches of amorphous carbon nanotubes (α-CNTs) have been successfully synthesized on a large scale from a solution-based reaction between ferrocene and carbon tetrachloride at 180 °C for 12 h. The α-CNT is 3−5 µm in length and ∼300/200 nm in diameter (outer/inner) and has a Brunauer–Emmett–Teller (BET) specific surface area of 431 m2 g−1 with a narrow pore distribution centered at 4.03 nm. The as-prepared α-CNTs showed a reversible capacity of ∼302 mA h g−1 and little hysteresis in the charge/discharge experiments of secondary lithium ion batteries, which suggested that the α-CNTs might become a new candidate as an electrode material in secondary lithium-ion batteries. Herein, a possible self-seeded surface-deposition growth mechanism of these α-CNTs has been proposed. This mechanism is of importance to understand the nucleation process in the solution phase and growth of other nanotubes through a similar seeded deposition process.
Co-reporter:Yuge Liu, Xiaomiao Feng, Jianmin Shen, Jun-Jie Zhu and Wenhua Hou
The Journal of Physical Chemistry B 2008 Volume 112(Issue 30) pp:9237-9242
Publication Date(Web):July 4, 2008
DOI:10.1021/jp801938w
A novel nanocomposite with a core−shell structure containing polystyrene (PS), polyaniline (PANI), and Au nanoparticles (NPs) was synthesized. The nanocomposite was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR). Cyclic voltammetric experiments indicated that the nanocomposite had excellent redox ability in a wide range of pH values. The existence of Au NPs resulted in a higher electrical conductivity of the nanocomposite. As a model, glucose oxidase (GOD) was entrapped onto the nanocomposite-modified glassy carbon electrode (GCE) and applied to construct a sensor. The immobilized GOD showed a pair of well-defined redox peaks and high catalytic activity for the oxidation of glucose.
Co-reporter:Qingming Shen, Liping Jiang, Hui Zhang, Qianhao Min, Wenhua Hou and Jun-Jie Zhu
The Journal of Physical Chemistry C 2008 Volume 112(Issue 42) pp:16385-16392
Publication Date(Web):2017-2-22
DOI:10.1021/jp8060043
A new and convenient sonoelectrochemical method was used to synthesize uniform three-dimensional (3D) dendritic Pt nanostructures (DPNs) at room temperature. The size and morphology of the final product could be controlled via simply adjusting the experiment parameters. The morphology and structure of the DPNs were characterized by transmission electron microscopy, high resolution transmission electron microscopy, field emission scanning electron microscopy, energy-dispersive X-ray, and X-ray diffraction. The formation process of the DPNs was carefully studied, and a spontaneous assembly mechanism was proposed based on the experimental results. Additionally, the electrocatalytic activity of the DPNs was evaluated using methanol and glucose as model molecules. The DPNs showed improved electrocatalytic activity toward methanol oxidation with respect to the monodisperse Pt nanoparticles; this improvement is due to the porosity structure and the greatly enhanced effective surface area. In addition, a sensitive enzyme-free biosensor can be easily developed for the detection of glucose in pH 7.4 phosphate buffer solution. The present method provides a new and simple strategy toward the fabrication of 3D DPNs with extensive applications.
Co-reporter:G. Yang;W. Hou;X. Feng;X. Jiang;J. Guo
Advanced Functional Materials 2007 Volume 17(Issue 17) pp:
Publication Date(Web):16 OCT 2007
DOI:10.1002/adfm.200700135
A theoretical study of polyaniline (PANI)/HNb3O8 layered nanocomposites has been performed based on ab initio calculations and experimental data. The Brønsted acidity of the layered niobic acid, and the interaction between the interlayered polyaniline molecules and the inorganic slabs in PANI/HNb3O8 nanocomposites, have been investigated. For the intercalation process of organic species into layered niobic acid, it is important to clarify whether the source of Brønsted acidity arises from the interlayered or hydrated protons. Thus, three inorganic layer structures, KNb3O8, HNb3O8, and HNb3O8·H2O, are evaluated, and the results show that there is only a minor contribution to the total acidity if the hydrogen is tightly bound by the inorganic slab. After the interlayered aniline monomers are polymerized within the acidic inorganic layers, two orientated structures of PANI molecules are calculated in which the interlayered C6 rings are perpendicular and parallel to the inorganic slabs, respectively, based on the experimental results. In comparison, PANI molecules in the latter orientation are placed in a relatively narrower interlayer space, and the hydrated proton cannot simultaneously form two effective hydrogen bonds with the O atom of Nb3O8– and an N atom of the PANI molecule because of the orientation requirement of the hydrogen bond. The interlayered hydrated proton cannot effectively transfer electrons between the PANI molecule and the inorganic slab. A similar conclusion is also reached from a detailed analysis of band structure and density of states (DOS). The calculated results are in good agreement with the experimental fact that a relatively higher conductivity is apparent in the former rather than in the latter.
Co-reporter:G. Yang;W. Hou;X. Feng;L. Xu;Y. Liu;G. Wang;W. Ding
Advanced Functional Materials 2007 Volume 17(Issue 3) pp:
Publication Date(Web):18 JAN 2007
DOI:10.1002/adfm.200500941
A detailed study on the intercalative polymerization of aniline within different layered inorganic acid hosts (HNb3O8, HTiNbO5, and HSr2Nb3O10) and the conformation and electrochemical properties of the resulting nanocomposites is presented. Two different mechanisms are proposed for the polymerization of monomers within the confined intralamella, initiated by chemical oxidants or microwave irradiation. The orientation of the aromatic rings and the extent of oxidation and protonation of the interlayered polyaniline (PANI) is closely related to the different layer properties. To emphasize the controlled structure–property relationship, the nanocomposites are modeled as “porous electrolytes” and analyzed by equivalent circuit, cyclic voltammetry (CV), and charge–discharge measurements. Compared with the nanocomposites in which the aromatic rings are parallel with the inorganic slabs, the nanocomposites in which the aromatic rings are perpendicular to the slabs demonstrate higher conductivity, electroactivity, and discharge capacity. In the latter, a good 2D channel for the insertion/desertion of ions was provided and simultaneously more ions could be reserved within a relatively wider space. A charge–discharge mechanism is suggested for the chemical reaction in the Li/PANI nanocomposite battery and is in good agreement with the experimental facts.
Co-reporter:Xianji Guo, Nianhua Xue, Shumin Liu, Xuefeng Guo, Weiping Ding, Wenhua Hou
Microporous and Mesoporous Materials 2007 Volume 106(1–3) pp:246-255
Publication Date(Web):1 November 2007
DOI:10.1016/j.micromeso.2007.03.003
Co-reporter:Gang Yang;Xiaomiao Feng;Wenhua Hou;Jun-Jie Zhu;Qin Xu
Macromolecular Rapid Communications 2006 Volume 27(Issue 1) pp:31-36
Publication Date(Web):19 DEC 2005
DOI:10.1002/marc.200500642
Summary: Polyaniline (PANI)/Au composite nanotubes and nanofibers are synthesized through a self-assembly process in the presence of camphorsulfonic acid and hydrochloric acid, as dopants, respectively. The PANI/Au composites are characterized by FT-IR, UV-vis, and thermogravimetric analysis to verify the incorporation of the Au nanoparticles and determine the Au content. Structural characterization is performed using SEM, TEM and X-ray diffraction. The presence of the Au nanoparticles results in an increased conductivity and improved crystallinity of the PANI. The self-assembly method employed here is a simple and inexpensive route to synthesize multifunctional nanotubes and nanofibers and could be extended to prepare other inorganic nanoparticle/PANI composites.
Co-reporter:Xiaomiao Feng;Yuge Liu;Gang Yang;Jun-Jie Zhu;Wenhua Hou
Journal of Applied Polymer Science 2006 Volume 101(Issue 3) pp:2088-2094
Publication Date(Web):24 MAY 2006
DOI:10.1002/app.23836
Polyaniline (PANI)/porous silica MCM-41 (MCM-41) composite was synthesized according to surface polymerization theory, and it was confirmed through comparing with PANI/solid silica (SiO2) by TGA and XPS techniques. The morphology and composition of the composite were also characterized by some techniques such as small-angle XRD, N2-adsorption isotherm, SEM, FTIR, and UV–vis. The thermal stability for the PANI/MCM-41 composite was enhanced when compared with that of pure PANI. With the increase in the concentration of HCl, the doping degree increased and UV-absorption peak at about 700 nm showed a red shift. The conductivity of the composite was enhanced by increasing the concentration of HCl. The results of FTIR showed that there was a strong interaction between PANI and MCM-41. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2088–2094, 2006
Co-reporter:Gang Yang, Wenhua Hou, Zhengzong Sun and Qijie Yan
Journal of Materials Chemistry A 2005 vol. 15(Issue 13) pp:1369-1374
Publication Date(Web):31 Jan 2005
DOI:10.1039/B415041D
A novel nanocomposite, PEO–LiV3O8, was synthesized by the intercalation of poly(ethylene) oxide (PEO) into the interlayers of LiV3O8 in one step. It was found that the two different components were combined on the nano-scale; the insertion of polymer was topotactic and did not cause structural changes in the layered host. The single-step weight loss (11.8 wt%) with TG/DSC measurement and other characterization results from XRD, FTIR, Raman, SEM, and TEM revealed that the putative molecular structure of PEO within the layers was similar to the zig-zag Type-I conformation of PEO–HgCl2. The inserted PEO chains decreased the interaction of the negative V3O8− layers with Li+ ions. Because a few interlayered PEO chains extended from the lamellae and connected further with each other, the adjacent PEO–LiV3O8 crystals were aggregated, thus providing a novel and suitable two-dimensional channel for Li+ ions to quickly transfer between the nancomposite grains. This particular hybrid structure of PEO–LiV3O8 resulted in an improvement of the electrochemical properties. The room temperature conductivity of PEO–LiV3O8 (2.99 × 10−4 S cm−1) was superior to that of the conventional SPEs (LiClO4–PEO, 1.1 × 10−7 S cm−1) and the host material LiV3O8 (8.68 × 10−5 S cm−1). Similar observations were also noted in other experimental parameters, such as the activation energy, diffusion coefficient of Li+ ions, and conductivity calculated by fitting EIS data.
Co-reporter:Chenhui Hu, Lihong Zhang, Liyuan Cheng, Jing Chen, ... Weiping Ding
Journal of Energy Chemistry (March 2014) Volume 23(Issue 2) pp:136-144
Publication Date(Web):1 March 2014
DOI:10.1016/S2095-4956(14)60128-5
H+-restacked nanosheets and nanoscrolls peeled from K4Nb6O17 display different structures and surface characters. The two restacked samples with increased surface areas have an amazing visible-light response for the photodegradation of dyes, which is superior to commercial TiO2 (P25) and Mb2O5. By comparison, H+/nanosheets have a relatively faster photodegradation rate originated from large and smooth basal plane. The work reveals that dye adsorbed on the unfolded nanosheets can effectively harvest sunlight. Due to facile preparation, low-cost and high photocatalytic efficiency, H+/nanosheets and H+/nanoscrolls might be used for the visible light-driven degradation of organic dyes as a substitute for TiO2 in industry.H+/nanosheets exhibited a faster photodegradation rate of dye than H+/nanoscrolls due to the high efficiency of sunlight-harvesting on the flat sheets.Download full-size image
Co-reporter:Ningna Chen, Jinhua Zhou, Qi Kang, Hongmei Ji, Guoyin Zhu, Yu Zhang, Shanyong Chen, Jing Chen, Xiaomiao Feng, Wenhua Hou
Journal of Power Sources (15 March 2017) Volume 344() pp:
Publication Date(Web):15 March 2017
DOI:10.1016/j.jpowsour.2017.01.119
•A two-step method was used to prepare amorphous VOPO4/graphene composites.•A phase transformation from crystalline to amorphous was occurred to VOPO4·2H2O.•Amorphous VOPO4 provide structure defects, larger channels and isotropic nature.•The VOPO4/graphene composites present unique layer-on-sheet hybrid nanostructure.•The VOPO4/graphene composites exhibit superior electrochemical performance.Amorphous vanadyl phosphate/graphene nanohybrids is successfully synthesized by first exfoliating bulk layered vanadyl phosphate (VOPO4·2H2O) into nanosheets, and then hydrothermal treatment with graphene oxide (GO). The electrochemical properties of the resulted materials are systematically investigated. It is found that a phase transformation from crystalline to amorphous is occurred to VOPO4·2H2O. As supercapacitor electrode material, the amorphous VOPO4/graphene composite exhibits a high specific capacitance (508 F g−1 at 0.5 A g−1), an excellent rate capability (359 F g−1 at 10 A g−1), and a good cycling stability (retention 80% after 5000 cycles at 2 A g−1). Particularly, it simultaneously has a greatly enhanced energy density of 70.6 Wh·kg−1 with a power density of 250 W kg−1. The outstanding energy storage performance mainly originates from the generation of amorphous VOPO4 phase that facilitates ion transport by shortening ion diffusion paths and provides more reversible and fast faradic reaction sites, the hybridization with graphene that greatly improves the electric conductivity and structure stability, and the unique layer-on-sheet nanohybrid structure that effectively enhances the structure integrity. This work not only provides a facile method for the preparation of amorphous VOPO4/graphene composites, but also demonstrates the enhanced energy density and rate capability of amorphous VOPO4-based materials for potential application in supercapacitors.Amorphous vanadyl phosphate/graphene composites with a unique layer-on-sheet hybrid nanostructure show excellent performances as supercapacitor electrode materials.Download high-res image (475KB)Download full-size image
Co-reporter:Xiaolin Liu, Wenxu Ji, Jiyuan Liang, Luming Peng and Wenhua Hou
Physical Chemistry Chemical Physics 2014 - vol. 16(Issue 38) pp:NaN20577-20577
Publication Date(Web):2014/08/12
DOI:10.1039/C4CP02960G
MoO2 hollow microspheres with tunable inner space have been synthesized through a hydrothermal process using MoO3 microbelts instead of bulk MoO3 as the precursor. It is found that the reactant morphology has a great impact on the product morphology and the inner space can be tuned by changing the amount of NaOH aqueous solution. An interesting evolutional process from MoO3 microbelts through a rose-like intermediate to MoO2 hollow microspheres has been clearly observed, and thus the possible formation mechanism is revealed. One layer of amorphous carbon has been subsequently coated on the surface of MoO2 hollow microspheres through a simple hydrothermal approach followed by annealing in argon. As the anode material for lithium ion batteries, MoO2@C hollow microspheres manifest excellent lithium-storage properties, such as high capacity (677 mA h g−1) and good cycling stability (negligible capacity fading even after 80 cycles). The significantly enhanced performance of MoO2@C hollow microspheres can be attributed to its unique structures, such as nanoscaled primary building blocks, carbon coating, hollow structure, and especially the synergy between the carbon coating and hollow structure.
Co-reporter:Xiaolin Liu, Wenhua Hou, Xiaoyan Yang and Qingming Shen
Dalton Transactions 2013 - vol. 42(Issue 32) pp:NaN11454-11454
Publication Date(Web):2013/05/30
DOI:10.1039/C3DT50562F
The selective synthesis of pure-phase La2(WO4)3 nanocrystals and uniform spindle-like NaLa(WO4)2 nano/microcrystals with tunable size based on one reaction system has been reported for the first time. The sodium ion is crucial for the selective synthesis of La2(WO4)3 and NaLa(WO4)2. An additional hydrothermal treatment has a great effect on the morphology of La2(WO4)3, while the hydrothermal temperature and time, and the amount of glycerine, significantly influence the morphology and size of NaLa(WO4)2. Based on the time-dependent experiments, it is proposed that the Ostwald ripening is the formation mechanism of the spindle-like NaLa(WO4)2. The resultant La2(WO4)3:Er3+ nanocrystals can emit a bright red color with a high purity under the excitation of 467 nm (blue region) and, more importantly, it can be easily dispersed in distilled water. The up-conversion emission intensity of NaLa(WO4)2:Yb3+/Er3+ is increased rapidly with the Yb3+ concentration under 980 nm laser excitation, suggesting the efficient energy transfer from Yb3+ to Er3+. Moreover, the emission color can be tuned from chartreuse to green by increasing the Yb3+ concentration. These unique properties of La2(WO4)3 and NaLa(WO4)2 are closely related with their distinctive crystal structures, and it is anticipated that the findings in this work may give an insight into the fabrication and application of the rare earth tungstates.
Co-reporter:Chao Liu, Ruirui Han, Hongmei Ji, Tao Sun, Jin Zhao, Ningna Chen, Jing Chen, Xuefeng Guo, Wenhua Hou and Weiping Ding
Physical Chemistry Chemical Physics 2016 - vol. 18(Issue 2) pp:NaN810-810
Publication Date(Web):2015/11/23
DOI:10.1039/C5CP06555K
The S-doped mesoporous nanocomposite (S-TNT) of HTiNbO5 nanosheets (NSs) and anatase TiO2 nanoparticles (NPs) with exposed {101} facets has been successfully synthesized by first mixing freeze-dried HTiNbO5 NSs with titanium isopropoxide and then calcination with thiourea in air. The exposed anatase {101} facets can act as a possible reservoir of the photogenerated electrons, yielding a highly reactive surface for the reduction of O2 to O2˙−. The partial substitution of Ti4+ by S6+ in the lattice of TiO2 NPs leads to a charge imbalance in S-TNT and the formation of Ti–O–S bonds. As a result, the formed cationic S-TNT favours adsorption of hydroxide ions (OH−ads) and thus captures the photo-induced holes to form hydroxyl radicals (˙OH). Moreover, with the formation of Ti–O–S bonds, partial electrons can be transferred from S to O atoms and hence the electron-deficient S atoms might capture photo-induced electrons. The surface-adsorbed SO42− could also act as an efficient electron trapping center to promote the separation of charge carriers. In addition, the Ti3+ species due to the removal of oxygen atoms during calcination and the associated oxygen vacancy defects on the surface of S-TNT could act as hole and electron scavengers, respectively. Besides, the closely contacted interface is formed between HTiNbO5 NSs and anatase TiO2 NPs due to the common features of TiO6 octahedra in two components, resulting in a nanoscale heterojunction structure to speed up the separation rate of photogenerated charge carriers. The formation of a nano-heterojunction and the incorporation of Ti3+ and S dopants give rise to the visible and near-infrared light response of S-TNT. The combined effects greatly retard the charge recombination and improve the photocatalytic activity for the degradation of rhodamine B (RhB) and phenol solution under visible light irradiation. The corresponding photocatalytic mechanism was investigated via the active species capture experiments. The present work may provide an insight into the fabrication of delicate composite photocatalysts with excellent performance.
Co-reporter:Xiaoyan Yang, Ye Zhang, Lin Xu, Zheng Zhai, Mingzhen Li, Meng Li, Xiaolin Liu and Wenhua Hou
Dalton Transactions 2013 - vol. 42(Issue 11) pp:NaN3993-3993
Publication Date(Web):2012/12/11
DOI:10.1039/C2DT32446F
For the first time, well-dispersed submicrometer-sized YVO4:Eu3+ hollow spheres were successfully synthesized though a surfactant-free method by employing Y(OH)CO3:Eu3+ colloidal spheres as a sacrificial template and NH4VO3 as a vanadium source. The synthetic process mainly consists of two steps, i.e., hydrothermal reaction and acid erosion. By simply changing the amount of NH4VO3 added, the textural parameters of the as-obtained hollow spheres, such as the inner diameter and shell-thickness, can be easily tuned. Moreover, double-shelled hollow spheres could also be obtained when the amount of NH4VO3 was increased to a certain extent. Particularly, the amorphous colloidal spheres of the template could be completely consumed when the amount of NH4VO3 was in large excess, giving rise to the direct formation of uniform hollow spheres without acid erosion. The possible formation process is discussed in detail. Under ultraviolet excitation, the obtained hollow YVO4:Eu3+ phosphors showed strong red emissions, and the Commission Internationale d'Eclairage (CIE) coordinates of the YVO4:Eu3+ phosphors were closely related with the textural parameters such as the inner diameter, shell-thickness and number of shells, indicating a size-dependent characteristic.
Co-reporter:Lihong Zhang, Chenhui Hu, Junfeng Zhang, Liyuan Cheng, Zheng Zhai, Jing Chen, Weiping Ding and Wenhua Hou
Chemical Communications 2013 - vol. 49(Issue 68) pp:NaN7509-7509
Publication Date(Web):2013/06/21
DOI:10.1039/C3CC42951B
Sulfur and iron co-doped titanoniobate nanosheets were prepared and evaluated in alcoholysis of styrene epoxide. The resultant co-doped catalyst exhibited excellent catalytic performance (yield of 99% with methanol as the nucleophile in only 1 h at room temperature) and may act as a promising candidate in many acid-catalyzed reactions.
Co-reporter:Hongmei Ji, Ting Wang, Yang Liu, Chunliang Lu, Gang Yang, Weiping Ding and Wenhua Hou
Chemical Communications 2016 - vol. 52(Issue 86) pp:NaN12728-12728
Publication Date(Web):2016/09/29
DOI:10.1039/C6CC05921J
A novel approach for hierarchically porous S-doped carbon was developed. Owing to the obviously reduced particle size and greatly enhanced meso-/macropores, electronic conductivity and surface polarity as well as the active sites available for Faradaic reactions, the resultant S-doped carbon electrode shows an excellent supercapacitor performance.
Co-reporter:Chao Liu, Liang Wu, Jing Chen, Ji-yuan Liang, Chang-shun Li, Hong-mei Ji and Wen-hua Hou
Physical Chemistry Chemical Physics 2014 - vol. 16(Issue 26) pp:NaN13417-13417
Publication Date(Web):2014/05/16
DOI:10.1039/C4CP01423E
An effective approach has been used to synthesize N-doped HTiNbO5 (denoted as N-HTiNbO5) with a better intercalation property. The synthesis of polyaniline (PANI) with N-HTiNbO5 to form PANI–N-HTiNbO5 lamellar nanocomposites by in situ polymerization using the aniline (ANI) intercalation compound ANI/N-HTiNbO5 as the intermediate has been investigated. The resulting PANI–N-HTiNbO5 nanocomposite showed a better crystallinity with a monolayer of PANI within the interlayers of N-HTiNbO5, because nitrogen doping can affect the surface charge distribution of [TiNbO5]− layers. The cyclic voltammetry (CV) results indicated that the PANI–N-HTiNbO5 nanocomposite had good redox activity and electrochemical-cycling stability in acidic solution. The visible-light response of the PANI–N-HTiNbO5 nanocomposite was enhanced through N-doping, acid exchange, and the intercalation of PANI. The PANI–N-HTiNbO5 nanocomposite showed the highest activity with 97.8% methylene blue (MB) photodegraded in 170 min under visible light irradiation. The significant enhancement of photocatalytic performance can be attributed to the high efficiency of charge separation, induced by the synergistic effect between PANI and N-HTiNbO5. In addition, the PANI–N-HTiNbO5 nanocomposite had a high thermal and photodegradation stability due to the intercalation reaction at the molecular level.
Co-reporter:Xiaolin Liu, Di Wu, Wenxu Ji and Wenhua Hou
Journal of Materials Chemistry A 2015 - vol. 3(Issue 3) pp:NaN972-972
Publication Date(Web):2014/11/24
DOI:10.1039/C4TA04373A
Uniform MoO2@C hollow nanospheres were facilely synthesized through a soft-templated hydrothermal method. This approach effectively integrates material fabrication and carbon coating into one step. Due to their unique structure characteristics, the resulting MoO2@C hollow nanospheres exhibited superior lithium-ion storage properties.
Co-reporter:Xiaomiao Feng, Yu Zhang, Zhenzhen Yan, Ningna Chen, Yanwen Ma, Xingfen Liu, Xiaoyan Yang and Wenhua Hou
Journal of Materials Chemistry A 2013 - vol. 1(Issue 34) pp:NaN9780-9780
Publication Date(Web):2013/06/14
DOI:10.1039/C3TA11856H
Polyaniline (PANI) nanotubes with improved electrochemical activity were synthesized by using a self-degradable MnO2 template and were developed as electrode materials for biosensors. The morphology, composition, and optical properties of the resulting products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), and cyclic voltammetry (CV). The results confirmed that the obtained PANI nanotubes had a perfect tubular structure with uniform diameters and lengths. Furthermore, PANI nanotubes were immobilized onto the surface of a glassy carbon electrode (GCE) and applied to construct a sensor. The obtained PANI-modified GCE showed high catalytic activity in the electrochemical oxidation of dopamine (DA) in a near neutral environment. Differential pulse voltammogram (DPV) results illustrated that the fabricated DA biosensor had high anti-interference ability towards uric acid (UA), ascorbic acid (AA), and glucose (GC). In addition, the fabricated biosensor showed superior performance with two wide linear ranges from 7 × 10−5 to 3 × 10−4 M and 3 × 10−4 to 5 × 10−3 M with a lower limit of detection of 0.5 × 10−9 M.
Co-reporter:Chao Liu, Ji-yuan Liang, Rui-rui Han, Yong-zheng Wang, Jin Zhao, Qian-jin Huang, Jing Chen and Wen-hua Hou
Physical Chemistry Chemical Physics 2015 - vol. 17(Issue 23) pp:NaN15172-15172
Publication Date(Web):2015/05/13
DOI:10.1039/C5CP01552A
S-doped Na2Ti6O13@TiO2 (S-TTO) core–shell nanorods, with exposed anatase TiO2 {101} facets, were synthesized by a facile calcination method. It was found that the addition of thiourea as the sulfur precursor was beneficial for the formation of anatase TiO2 with a better crystallinity and the doped sulfur atoms favorably stabilized the anatase structure. The substitution of Ti4+ by S6+ in the lattice of S-TTO gave rise to the visible light response and increased the amount of active groups typically as a hydroxyl radical adsorbed onto the catalyst surface. With the formation of the Ti–O–S bond, partial electrons could be transferred from S to O atoms. The electron-deficient S atoms might capture e− and thus inhibit the recombination of photogenerated electron–hole pairs. Meanwhile, a closely contacted interface was formed between Na2Ti6O13 and anatase TiO2, resulting in a nanoscale heterojunction structure to speed up the separation rate of photogenerated charge carriers. The exposed anatase {101} facets could act as possible reservoirs of the photogenerated electrons, yielding a highly reactive surface for the reduction of O2 to O2˙− and thus the decrease of recombination probability of electron–hole pairs. In addition, the anisotropically shaped titanate nanorods provided a pathway for the quick transport of charge carriers throughout the longitudinal direction. The combined effects of S doping, nano-heterojunction formation and morphology engineering led to an obviously enhanced photocatalytic performance for the degradation of methylene blue (MB) solution under visible light irradiation. The corresponding photocatalytic mechanism was investigated and discussed in detail. The present work may provide an insight into the fabrication of delicate composite photocatalysts with excellent performance.
Co-reporter:Zheng Zhai, Chenhui Hu, Xiaoyan Yang, Lihong Zhang, Chao Liu, Yining Fan and Wenhua Hou
Journal of Materials Chemistry A 2012 - vol. 22(Issue 36) pp:NaN19131-19131
Publication Date(Web):2012/07/16
DOI:10.1039/C2JM32338A
Nitrogen-doped mesoporous nanohybrids of TiO2 nanoparticles and HTiNbO5 nanosheets have been successfully synthesized by first exfoliating layered HTiNbO5 in tetrabutylammonium hydroxide (TBAOH) to obtain HTiNbO5 nanosheets, then reassembling with TiO2 colloids and finally heating with urea in air at 450 °C. The resulting samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), X-ray photoelectron spectroscopy (XPS), UV-vis spectroscopy, laser Raman spectroscopy (LRS) and N2 adsorption–desorption measurements. It was found that the TiO2 nanoparticles existed in the anatase phase and the titanoniobate nanosheets were still maintained after nitrogen doping. The obtained nitrogen-doped nanohybrids showed a greatly expanded surface area with a mesoporous structure and the doped nitrogen atoms were located in the interstitial sites of TiO2, giving rise to the visible light response. The catalytic activities of the obtained samples were evaluated by the photodegradation of rhodamine B (RhB) solution under visible light irradiation. The obtained N-doped nanohybrid had a higher activity than N-doped HTiNbO5 nanosheets and N-doped TiO2, indicating the synergetic effect of TiO2 nanoparticles and HTiNbO5 nanosheets. The dye molecules were mainly degraded to aliphatic organic compounds and mostly further mineralized to CO2 and/or CO, rather than being simply decolorized. In addition, the cell viability results of the HepG2 cells showed that the as-prepared sample had a good biocompatibility.
