Co-reporter:Yanyang Han, Fei Wang, Chin Yan Lim, Hong Chi, Dairong Chen, FuKe Wang, and Xiuling Jiao
ACS Applied Materials & Interfaces September 27, 2017 Volume 9(Issue 38) pp:32418-32418
Publication Date(Web):September 6, 2017
DOI:10.1021/acsami.7b08399
In this work, we report the first hybrid nanosized photoinitiators with low cytotoxicity and migration by coupling of polyhedral oligomeric silsesquioxanes (POSS) to benzophenone derivatives. This new series of photoinitiators were fully characterized and showed many favorable properties such as uniform sizes, extremely low tendency to migrate, less effect on resin viscosity, enhanced thermal stability and mechanical strength, increased photoactivity, and significantly lower cell toxicity compared to their corresponding benzophenone molecules. The utility of these hybrid nanosized photoinitiators in 3D printing was demonstrated in printing of various 3D structures with high resolution and accuracy.Keywords: 3D printing safety; additive manufacturing; benzophenone; photoinitiators; POSS; printable resin;
Co-reporter:Hanyu Wang;Dairong Chen
The Journal of Physical Chemistry C December 4, 2008 Volume 112(Issue 48) pp:18793-18797
Publication Date(Web):2017-2-22
DOI:10.1021/jp805591y
A facile thermal-decomposition route to the monodispersed Ni nanoparticles was introduced, in which the cheap and low toxic nickel acetate was used as precursor and the surfactant hexadecylamine was used as solvent, reducing agent, and stabilizing agent. The product was characterized in detail by using X-ray diffraction, transmission electron microscope (TEM), high-resolution TEM, thermal- gravimetric, and Fourier transform infrared techniques. The effects of reaction parameters such as reaction temperature, time, and the molar ratio of reagents on the phase and size of Ni nanoparticles were investigated, and the transformation of face-centered cubic- (fcc) to hexagonal close-packed-phase was also discussed. Furthermore, the magnetic properties of fcc-Ni nanoparticles with tunable size were measured and compared by superconducting quantum interference device magnetometer.
Co-reporter:Fanxia Kong;Yuguo Xia;Dairong Chen
New Journal of Chemistry (1998-Present) 2017 vol. 41(Issue 15) pp:7562-7570
Publication Date(Web):2017/07/24
DOI:10.1039/C7NJ01560G
Controlling overexposed facets with high energy is pivotal for various applications, particularly catalytic reactions which occur on the surfaces of nanostructures. Herein, we report a combined solvothermal and etching method to synthesize anatase TiO2 nanocrystals with energetic exposed facets, which exhibit enhanced visible light photodegradation activity towards RhB. Electron microscopic photographs revealed that the initially prepared nanocrystals had a hierarchical structure stacked by secondary nanoplates, and time dependent experiments proved that the formation process followed an oriented aggregation mechanism and a subsequent grain growth. In addition, quantum mechanical calculations revealed that the etching process could occur along three directions of TiO2 nanocrystals, and the formation of Ti3+ defects was thermodynamically favorable, which was further demonstrated by XPS spectra. The reasons for the enhanced photodegradation activity are also discussed through the production of reactive oxygen species (ROS), which revealed that the adsorption of surface hydroxyls and H2O may be the main reason for this enhancement.
Co-reporter:Yanyang Han;Chee Chuan J. Yeo;Dairong Chen;Fei Wang;Yiting Chong;Xu Li;FuKe Wang
New Journal of Chemistry (1998-Present) 2017 vol. 41(Issue 16) pp:8407-8412
Publication Date(Web):2017/08/07
DOI:10.1039/C7NJ02145C
3D printing, as a type of additive manufacturing, has offered great potential for creating sophisticated geometric shapes compared to traditional processing techniques. Here, we report a nanowire-based photopolymerizable resin with enhanced printing accuracy and improved long-term accuracy, which are of paramount importance to liquid resin-based 3D printing. Transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to characterize the as-prepared boehmite and γ-Al2O3 nanowires. Curing depth and prototype printing were used to better understand the mechanism of nanowire incorporation enhanced printing accuracy. Meanwhile, dynamic mechanical analysis (DMA) and tensile tests results showed reinforced thermal mechanical properties. This report offers a promising approach to improve both printing accuracy and mechanical properties of the printed objects for current liquid resin-based 3D printing technologies.
Co-reporter:Hong Zhang;Cheng Li;Dairong Chen;Jingmei Zhao;Yuguo Xia
CrystEngComm (1999-Present) 2017 vol. 19(Issue 15) pp:2057-2064
Publication Date(Web):2017/04/10
DOI:10.1039/C7CE00384F
For thermochromic materials, a fine-tuning thermochromic property is always pursued to in order to realize their full potential. However, to date, realizing the fine-tuning still remains a great challenge and is seldom reported. In the present work, the Prussian blue analogue, Co3[Co(CN)6]2, with fine-tuning color transition temperature is synthesized through a facile wet-chemical method. By simply adjusting the amount of sodium citrate in the system, part of the ligand water molecules coordinated to lattice Co(II) can be substituted by citrate, which is confirmed by DFT calculations and experimental results, resulting in a color transition versus temperature as a response to a coordination environmental change of the Co(II). Finally, a fine-tuning color transition temperature from 40 to 80 °C is realized with the color changing from pink to blue upon heating. In addition to the tunable color transition temperature, a high color transition speed and long term stability were also achieved due to the porous and stable lattice structure of Co3[Co(CN)6]2. To the best of our knowledge, this is the first report of a metal–organic framework (MOF) with a fine-tuning reversible thermochromic property, and the present controlled strategy might be expanded to the preparation of other similar materials.
Co-reporter:Nao Han, Dairong Chen, Yingping Pang, Zhiming Han, Yuguo Xia, Xiuling Jiao
Electrochimica Acta 2017 Volume 235(Volume 235) pp:
Publication Date(Web):1 May 2017
DOI:10.1016/j.electacta.2017.03.122
Increasing demand for high energy capability Li rechargeable batteries has promoted extensive research on the development of electrode materials. Multi-component spinel metal-oxide is considered to be promising anode material owing to their better electrical conductivity and higher electrochemical activity. Herein, a facile one-pot strategy without further thermal annealing treatment is successfully developed for preparation of well-defined ZnGa2O4 nanocubes. To the best of our knowledge, this is the first report on the synthesis of ZnGa2O4 nanocubes through wet chemical method and applied as anode material. Galvanostatic charge and discharge results indicate ZnGa2O4 nanocubes electrode is capable of delivering a higher capacity and better cycling stability than ZnO/Ga2O3 mixture electrode. Noteworthily, ZnGa2O4 nanocubes electrode also exhibites superior capacity compared with ZnGa2O4 nanospheres electrode which is consisted of secondary nanoparticles. Large amount of ZnGa2O4 nanocubes could retain their morphology after 160 charge/discharge cycles and further surface elemental analysis illustrates elements distributions has no changes in the surface. The unique structure and high crystallinity is responsible for higher capacity and better cycling stability.
Co-reporter:Yingping Pang, Jian Zhang, Dairong Chen and Xiuling Jiao
RSC Advances 2016 vol. 6(Issue 36) pp:30395-30400
Publication Date(Web):15 Mar 2016
DOI:10.1039/C5RA27715A
A cost-effective but efficient two-step solvothermal calcination strategy for the preparation of novel three-dimensional (3D) open hierarchical NiO nanoflowers was demonstrated. The nanostructured flowers, assembled by nanosheets with high porosity resulting from many interparticle mesopores, afford a large specific surface area and interlayer space for ion intercalation. The as-prepared NiO nanoflowers possess promising fast charge transfer, remarkable structural integration, as well as high electroactive surface area (ECSA). Remarkably, electrochemical testing in Li-ion batteries showed that the NiO nanoflowers, as a high-performance anode, are capable of delivering a superior specific capacity, high cycling stability, as well as good rate capacity. The excellent electrochemical performance may be attributed to the unique well-defined self-assembled NiO nanoflowers with 3D open hierarchical structures.
Co-reporter:Jian Zhang; Xiu-Ling Jiao;Dr. Yu-Guo Xia;Fang-Fang Liu;Ying-Ping Pang;Xin-Fu Zhao; Dai-Rong Chen
Chemistry - A European Journal 2016 Volume 22( Issue 27) pp:9321-9329
Publication Date(Web):
DOI:10.1002/chem.201600172
Abstract
A facile liquid-phase exfoliation method to prepare few-layer FeOCl nanosheets in acetonitrile by ultrasonication is reported. The detailed exfoliation mechanism and generated products were investigated by combining first-principle calculations and experimental approaches. The similar cleavage energies of FeOCl (340 mJ m−2) and graphite (320 mJ m−2) confirm the experimental exfoliation feasibility. As a Fenton reagent, FeOCl nanosheets showed outstanding properties in the catalytic degradation of phenol in water at room temperature, under neutral pH conditions, and with sunlight irradiation. Apart from the increased surface area of the nanosheets, the surface state change of the nanosheets also plays a key role in improving the catalytic performance. The changes of charge density, density of states (DOS), and valence state of Fe atoms in the exfoliated FeOCl nanosheets versus plates illustrated that surface atomistic relationships made the few-layer nanosheets higher activity, indicating the exfoliation process of the FeOCl nanosheets also brought about surface state changes.
Co-reporter:Jian Zhang, Yuguo Xia, Li Zhang, Dairong Chen and Xiuling Jiao
Physical Chemistry Chemical Physics 2015 vol. 17(Issue 41) pp:27391-27398
Publication Date(Web):16 Sep 2015
DOI:10.1039/C5CP03859F
In-depth understanding of the sol–gel process plays an essential role in guiding the preparation of new materials. Herein, the effects of different inorganic acids (HCl, HNO3 and H2SO4) and divalent hydrated metal cations (Mg2+, Ca2+, Co2+, Ni2+) on γ-AlOOH sol–gel process were studied based on experiments and density functional theory (DFT) calculations. In these experiments, the sol originating from the γ-AlOOH suspension was formed only with the addition of HCl and HNO3, but not with H2SO4. Furthermore, the DFT calculations showed that the strong adsorption of HSO4− on the surface of the γ-AlOOH particles, and the hydrogen in HSO4− pointing towards the solvent lead to an unstable configuration of electric double layer (EDL). In the experiment, the gelation time sequence of γ-AlOOH sol obtained by adding metal ions changed when the ionic strength was equal to or greater than 0.198 mol kg−1. The DFT calculations demonstrated that the adsorption energy of hydrated metal ions on the γ-AlOOH surface can actually make a difference in the sol–gel process.
Co-reporter:Wei Li, Yan Wang, Botao Ji, Xiuling Jiao and Dairong Chen
RSC Advances 2015 vol. 5(Issue 72) pp:58120-58127
Publication Date(Web):25 Jun 2015
DOI:10.1039/C5RA09198E
Flexible CeO2–TiO2 fibrous membrane was prepared by an electrospinning combined sol–gel method. The composition, structure, and morphology of the membrane were thoroughly investigated with XRD, FT-IR, N2 adsorption–desorption, SEM and TEM. The tensile-strength of the TiO2–CeO2 was evaluated with a tensile tester and the highest strength (1.38 MPa) was attained at a Ce and Ti molar ratio of 5:100, which was 3 times as high as that of pure TiO2. After Pd was loaded on the fibers, the strength of fibrous membrane (1.28 MPa) stayed almost the same. Moreover, the Pd/CeO2–TiO2 fibrous membrane exhibits high thermal stability against long time usage and retains its strength up to 1.22 MPa after 400 °C for 20 h. Strength performance is mainly due to effective size control of the particles composing the nanofibers; this endows the fibrous membrane with application potential for high efficiency particle filtration. The best filtration performance had an efficiency of 99.86% and a corresponding pressure drop of 178 Pa. At the same time, the fibrous membrane also exhibits good low-temperature CO oxidation performance with a complete conversion of CO to CO2 at 200 °C and no decrease of catalytic activity over 30 h. The excellent properties of this Pd/CeO2–TiO2 fibrous membrane enrich the applications of inorganic fibrous membranes simultaneously for air filtration and catalysis.
Co-reporter:Na Tang, Bo Chen, Yuguo Xia, Dairong Chen and Xiuling Jiao
RSC Advances 2015 vol. 5(Issue 67) pp:54433-54438
Publication Date(Web):15 Jun 2015
DOI:10.1039/C5RA07638B
Facile synthesis of uniform cubic cuprous oxide (Cu2O) nanocages has been realized via an acidic etching method without any surfactant at 35 °C. The edge length of the Cu2O nanocages was 80–90 nm, and the thickness of the walls was about 5 nm. Moreover, the wall thickness of these nanocages could be adjusted by changing the reaction temperature. The formation mechanism of the Cu2O nanocages was investigated. Ascorbic acid played an important role in this experiment. Owing to its reducing action, Cu(OH)2 was first reduced to solid Cu2O nanocubes in an aqueous solution. Almost immediately these nanocubes were etched into hollow ones through the acidic etching effect. Eventually, Cu2O nanocages which had thinner walls and more complete structures than those previously mentioned were produced in the presence of hydrazine hydrate (N2H4·H2O). The as-prepared Cu2O nanocages have superior gas sensing performance toward gasoline comparing with the solid Cu2O nanocubes.
Co-reporter:Wei Li, Cheng Li, Bo Chen, Xiuling Jiao and Dairong Chen
RSC Advances 2015 vol. 5(Issue 43) pp:34281-34291
Publication Date(Web):07 Apr 2015
DOI:10.1039/C5RA04100G
Sheet-like N–TiO2/g-C3N4 heterojunctions with well-controlled structures as high-efficiency visible-light photocatalysts were synthesized by direct co-calcination of preformed N–TiO2 nanoparticles and g-C3N4 nanosheets. The composition, structure, morphology, and optical absorption properties of the as-prepared g-C3N4 nanosheets and N–TiO2/g-C3N4 heterojunctions were thoroughly investigated with XRD, FT-IR, SEM, TEM, XPS, and UV-vis DRS, respectively. The visible-light photocatalytic activity of the heterojunctions with different N–TiO2/g-C3N4 mass ratios was evaluated by photodegradation of rhodamine B dye and the highest enhancement was attained at a mass ratio of 1:3, which was 19 and 5.3 times as high as that of the individual N–TiO2 nanoparticles and g-C3N4 nanosheets, respectively. The photocatalytic activity of the composites originating from nanosheets is 11 times as high as that of the bulk g-C3N4/N–TiO2 heterojunctions. Moreover, the sheet-like N–TiO2/g-C3N4 photocatalyst exhibits excellent stability against repeated use and could still retain over 98.8% of the initial activity after seven cycles. Such a good visible-light photocatalytic performance is mainly due to the effective structure and chemical composition provided by the present method, which endow the as-prepared heterojunctions with exceptionally high specific surface area (>80 m2 g−1) as well as efficient charge transfer at the heterojunction interfaces. The charge separation mechanism during the photodegradation process was also studied and a possible photocatalytic mechanism was proposed.
Co-reporter:Yuguo Xia, Li Zhang, Yan Wang, Xiuling Jiao, Dairong Chen
Materials Letters 2015 Volume 143() pp:294-297
Publication Date(Web):15 March 2015
DOI:10.1016/j.matlet.2014.12.120
•Mesoporous γ-Al2O3 microcubes are synthesized through a facile thermal decomposition route.•Mesoporous γ-Al2O3 exhibits high thermal stability.•The product has high adsorption capacity and good recycling ability towards aqueous Cr(VI).A facile route is initiated to fabricate well-defined mesoporous γ-Al2O3, with a three-dimensional micro/nanostructure, using basic aluminum sulfate (BAS) microcubes as precursor. The as-synthesized γ-Al2O3 is cubic-like in morphology with an average size of ca. 6 μm. Mesoporous γ-Al2O3 synthesized by this method is highly thermal stable and exhibits superior adsorption performance (maximum adsorption capacity 9.93 mg/g) with good recycling efficiency (more than 76% of its original adsorption capacity after 4 cycles) as an adsorbent to remove the heavy metal ions Cr(VI) as a result of its unique structure, which made it to be a promising material for environmental remediation.
Co-reporter:Jian Zhang
The Journal of Physical Chemistry C 2015 Volume 119(Issue 24) pp:13915-13921
Publication Date(Web):May 27, 2015
DOI:10.1021/acs.jpcc.5b02293
The segregation mechanism of metal ions (Na+, K+, Mg2+, Ca2+, Co2+, Ni2+, La3+, Y3+) in γ-AlOOH was investigated during the sol–gel process by a combination of experiments and density functional theory (DFT) calculations. The DFT calculations showed that all of the adsorption energies of metal ions were smaller than the hydrogen ion in neutral conditions, and the metal ions even could not be adsorbed on the protonated γ-AlOOH surface due to electrostatic repulsion. The segregation of metal ions in γ-AlOOH sol during the drying process was caused by weak adsorption of metal ions on the γ-AlOOH surface in acidic conditions and mainly occurred at the late period of drying with the removal of adsorbed water. The computational segregation sequence of metal ions was consistent with experimental results, which was La3+ ≈ Y3+ > Ni2+ ≈ Co2+ > Mg2+ ≈ Ca2+ > K+ ≈ Na+. According to the segregation mechanism during sol–xerogel transition, it is speculated that an additive which could strengthen the combination between metal ions and the protonated γ-AlOOH surface could diminish the segregation. On the basis of this speculation, citric acid was added into the γ-AlOOH sol, and the segregation percentage of La3+ decreased to 3.54% from 16.4%.
Co-reporter:Yan Wang, Wei Li, Yuguo Xia, Xiuling Jiao and Dairong Chen
Journal of Materials Chemistry A 2014 vol. 2(Issue 36) pp:15124-15131
Publication Date(Web):22 Jul 2014
DOI:10.1039/C4TA01770F
Novel self-standing γ-alumina fibrous membranes with good flexibility have been successfully fabricated for the first time using an electrospinning technique. The γ-alumina membranes were composed of randomly arranged nanofibers with a high aspect ratio and small diameter (ca. 230 nm). The γ-alumina membranes show high tensile strength (2.98 MPa) and thermal stability (up to 900 °C), which favor their applications in high temperature conditions. Furthermore, the γ-alumina membranes exhibit good filtration performance for 300 nm dioctyl phthalate fine particulate gas filtration. The filtration efficiency is 99.848% and the pressure drop is 239.12 Pa for the membrane calcined at 700 °C with a basis weight of 9.28 g m−2; and the filtration efficiency could be over 99.97% when the basis weight is over 11.36 g m−2, suggesting that the γ-alumina fibrous membrane is a promising candidate for high temperature, fine particulate filtration applications. This work also provides a novel insight into the electrospinning of flexible self-standing inorganic membranes for applications in the separations field.
Co-reporter:Yuguo Xia, Bo Chen, Xiuling Jiao and Dairong Chen
Physical Chemistry Chemical Physics 2014 vol. 16(Issue 12) pp:5866-5874
Publication Date(Web):03 Feb 2014
DOI:10.1039/C4CP00090K
Cube-like basic aluminium sulfate crystals were prepared by a facile template-free hydrothermal strategy. The microstructures, morphologies and textural properties of as-synthesized material were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy. X-ray crystallography reveals that cubic basic aluminium sulfate possesses a single crystal nature. Chemical formation mechanism studies of sulfuric acid with γ-AlOOH were performed using a combined experimental and computational approach. Time dependent experiments reveal that formation of basic aluminium sulfate is based on the dissolution–recrystallization process, and the source of Al3+ is from the dissolution of γ-AlOOH at high H+ concentration. Moreover, the quantum mechanical calculations reveal that dramatic structural changes occurred in the (100) plane at high H+ concentration, which is inferred to be the initiation of the source of Al3+. Meanwhile, surface energy calculations can well explain the exposed plane of basic aluminium sulfate microcubes, which are consistent with the XRD results. Besides, equations to quantitatively describe the relationship between the molar amount of H+ and the final phase are proposed, which has been confirmed by experimental results.
Co-reporter:Feng Liu, Qifang Lu, Xiuling Jiao and Dairong Chen
RSC Advances 2014 vol. 4(Issue 78) pp:41271-41276
Publication Date(Web):15 Aug 2014
DOI:10.1039/C4RA06800A
Four types of nylon-6/POMs (H3+nPMo12−nVnO40·xH2O and H3PW12O40·xH2O) composite nanofibrous membranes were fabricated by electrospinning the mixed solution of nylon-6 and POMs using HCOOH and water as solvents. The membranes were composed of randomly arranged nylon-6/POMs composite nanofibers with diameter range from 50 to 100 nm. Thermal gravimetric (TG) and differential scanning calorimetric (DSC) characterizations indicate high thermal stability of the membranes. The degradation ability of the composite fibrous membranes toward mustard (HD) was investigated. The results showed that the membrane has a good degradation performance toward HD with the degradation percentage as high as 41.55%. The degradation rates of HD by the four types of nanofibrous membranes are in the order of nylon-6/PMoV3 > nylon-6/PMoV2 > nylon-6/PW > nylon-6/PMoV1. The nanofibrous membrane simultaneously exhibit good filtration performance toward aerosol. The fabricated composite nanofibrous membranes show potential application in the in situ degradation of HD, and may be applied as a protecting cloth.
Co-reporter:Yan Wang, Wande Ding, Xiuling Jiao and Dairong Chen
RSC Advances 2014 vol. 4(Issue 58) pp:30790-30797
Publication Date(Web):19 Jun 2014
DOI:10.1039/C4RA03912B
Flexible core–shell fibrous membranes for mesoporous alumina-based adsorbents have been fabricated via a one-step coaxial electrospinning, which was accomplished by electrospinning silica as the core phase and mesoporous alumina as the shell phase. The core–shell fibers could be directly electrospun in the form of membranes. After calcination, a mesoporous alumina shell formed to give a high adsorption capacity, and the core fibers became dense to provide good mechanical property of the membrane. The membranes exhibit good adsorption properties toward Congo red and also can maintain the membrane form during the cyclic test, which makes them easy to handle and retrieve. The good adsorption performance, high mechanical property, easy recovery and reuse characteristic of the fibrous membranes, as well as their easy to scale-up fabrication process all facilitate their practical application in environmental remediation.
Co-reporter:Yan Wang, Wei Li, Xiuling Jiao and Dairong Chen
Journal of Materials Chemistry A 2013 vol. 1(Issue 36) pp:10720-10726
Publication Date(Web):26 Jun 2013
DOI:10.1039/C3TA10955K
Mesoporous alumina fibers were successfully synthesized via an electrospinning technique combined with a sol–gel method in the presence of a triblock copolymer as a structure directing agent. The amorphous alumina fibers derived from the electrospun xerogel fibers after calcinations at 450 °C and the γ-Al2O3 fibers obtained after the xerogel fibers were calcined at 700 °C exhibit uniform mesopores with fiber diameters of 130–200 nm, and BET surface areas up to 264.1 m2 g−1 and 242.6 m2 g−1, respectively. After the xerogel fibers were calcined at 1100 °C, with the transformation from γ-Al2O3 to α-Al2O3, a significant grain growth occurs and the mesopores disappear. Further investigation indicates that the γ-Al2O3 fibers have good adsorption properties toward Congo red with a maximum adsorption capacity of 781.25 mg g−1 for the sample obtained at 700 °C. In addition, the fibers show a good stability in acidic conditions and during a reuse process, which indicates their potential applications in adsorption as well as related areas, such as catalysis and catalyst supports.
Co-reporter:Zhanxia Shu, Xiuling Jiao and Dairong Chen
CrystEngComm 2013 vol. 15(Issue 21) pp:4288-4294
Publication Date(Web):15 Mar 2013
DOI:10.1039/C3CE40234G
Tetragonal star-like ZrO2 nanostructures were prepared using ZrOCl2·8H2O and CH3COONa as raw materials via a hydrothermal process. The zirconia nanostructures were investigated in detail by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution TEM (HR-TEM), infrared (IR) spectrum, thermal-gravimetry (TG) and other techniques, and possible formation mechanism was proposed. In the formation of the tetragonal star-like zirconia nanostructures, acetate played an important role due to the adsorption on certain of the crystal's facets. Tetragonal star-like zirconia showed excellent selective photocatalytic activity for the photodegradation of anionic dyes (methyl orange, congo red and rhodamine B) in acidic, neutral and weak basic aqueous solutions.
Co-reporter:Yuguo Xia, Li Zhang, Xiuling Jiao and Dairong Chen
Physical Chemistry Chemical Physics 2013 vol. 15(Issue 41) pp:18290-18299
Publication Date(Web):09 Sep 2013
DOI:10.1039/C3CP53110D
The investigation of the metal oxide/inorganic ion interface at the atomic level represents a fundamental issue for the understanding of chemical and physical processes involved in several fields such as catalysis, adsorption, directed synthesis and the mechanistic study of crystal growth. In this paper, a combined hydrothermal synthesis and computational approach based on DFT theory is adopted to investigate the effects of sulfate ions on the final morphology of γ-AlOOH. The quantum mechanical calculations reveal that the sulfate ions interact with γ-AlOOH facets through surface hydroxyls and act as a morphology-directing agent. The adsorption type and chemical bonds between the sulfate ion and γ-AlOOH are discussed. The formation of nanosheets and nanorods of γ-AlOOH is controlled by thermodynamic factors. Moreover, the HR-TEM images reveal the growth directions and exposed planes of boehmite, indicating an oriented-aggregation process which is consistent with the DFT calculations. Overall, all the morphologies of boehmite suggested by the calculations are confirmed by experimental results.
Co-reporter:Haiyan Sun;Yanyang Han;Zhen Jiang;Dairong Chen
European Journal of Inorganic Chemistry 2013 Volume 2013( Issue 1) pp:109-114
Publication Date(Web):
DOI:10.1002/ejic.201201159
Abstract
Sphere-like Fe3O4 aggregates were solvothermally prepared with ethylene glycol, sodium acetate and FeCl3·6H2O as raw materials. The sphere-like Fe3O4 aggregates provided heterogeneous growth sites for Au nanoparticles. These were obtained by reduction of HAuCl4 by sodium citrate under mild reaction conditions and the Fe3O4-Au nanocomposites were subsequently formed. The peroxidase-like activity of nanocomposites was studied with H2O2 and 3,3′,5,5′-tetramethylbenzidine as substrates. Fe3O4-Au nanocomposites exhibited better catalytic activity than pure Fe3O4 aggregates, mainly resulting from the special electronic structure at the interfaces between the sphere-like Fe3O4 aggregates and the gold nanoparticles.
Co-reporter:Yuguo Xia, Xiuling Jiao, Yongjun Liu, Dairong Chen, Li Zhang, and Zhenhua Qin
The Journal of Physical Chemistry C 2013 Volume 117(Issue 29) pp:15279-15286
Publication Date(Web):June 29, 2013
DOI:10.1021/jp402530s
Identification of the key factors of morphology control in nanomaterial synthesis is important for mechanism understanding of the reactivity–structure relationship and rational design of crystals with desired morphology. Among others, the inorganic ions in solution were found to be a key factor in controlling the final morphology. To reveal the effect of inorganic ions, the boehmite with different morphologies influenced by chloride ions is studied by a combined experimental and computational approach. The quantum mechanical calculations reveal that the chloride ions interact with crystal planes through surface hydroxyls and act as morphology-directing agent. The growth directions and exposed planes of the boehmite determined from HR-TEM images indicate an oriented-aggregation process which is consistent with the DFT calculations. It is envisaged that the defects caused by excessive hydrochloric acid are due to its dissolving property combined with the reduction of adsorption energies. Overall, all the morphologies of boehmite suggested by the calculations are confirmed by experimental results.
Co-reporter:Huijuan Tang, Haiyan Sun, Dairong Chen, Xiuling Jiao
Materials Letters 2012 Volume 77() pp:7-9
Publication Date(Web):15 June 2012
DOI:10.1016/j.matlet.2012.02.122
The Pt/CeO2 nanofibers with diameter of 80–120 nm were prepared by electrospinning method with Ce(NO3)3·6H2O as raw material and PVP as spinnable additive. This method included the preparation of spinnable sol and electrospinning process. After calcination at 400 °C, the fluorite structure Pt/CeO2 nanofibers with loose structure were obtained, which were composed of 5–10 nm particles. In the water–gas shift reaction, 1 wt.% Pt doped CeO2 nanofibers exhibited superior catalytic activity compared with pure CeO2 nanofiber, Pt loaded CeO2 powder and Pt loaded CeO2 nanofiber, and the CO conversion reaches 98% at 320 °C and maintains that until 360 °C, showing potential application in water–gas shift reaction.Highlights► The fluorite structure Pt/CeO2 nanofibers were prepared by electrospinning method. ► The Pt/CeO2 nanofibers were composed of nanoparticles with size of 5–10 nm. ► The Pt/CeO2 fibers exhibited high catalytic activity in water-gas shift reaction.
Co-reporter:Huijuan Tang, Haiyan Sun, Dairong Chen, Xiuling Jiao
Materials Letters 2012 70() pp: 48-50
Publication Date(Web):
DOI:10.1016/j.matlet.2011.11.111
Co-reporter:Haiyan Sun, Xiuling Jiao, Hanyu Wang, Zhen Jiang, and Dairong Chen
ACS Applied Materials & Interfaces 2011 Volume 3(Issue 7) pp:2425
Publication Date(Web):June 23, 2011
DOI:10.1021/am200330b
Monodispersed Pd nanoparticles and their porous spherelike aggregates with different lattice parameters were solvothermally prepared under nitrogen and air atmospheres. Here PdCl2 acted as Pd precursor and hexadecylamine played the roles of solvent, reductant, and surface capping agent. Oxygen existing in air resulted in the change of surface capping agent, which then induced the aggregation of Pd nanoparticles, and the incorporation of oxygen led to the expansion of its lattice parameter to 0.398 nm, whereas the standard lattice parameter in metallic Pd is 0.389 nm. The monodispersed nanoparticles presented better catalytic activity and stability for the oxidation of methanol than the sphere-like Pd aggregates.Keywords: electrocatalyst; methanol oxidation; monodispersed nanoparticle; palladium; porous sphere-like aggregates; reaction atmosphere;
Co-reporter:Botao Ji, Dairong Chen, Xiuling Jiao, Zhongqiang Zhao, Yingxun Jiao
Materials Letters 2010 Volume 64(Issue 16) pp:1836-1838
Publication Date(Web):31 August 2010
DOI:10.1016/j.matlet.2010.05.026
Nanoporous barium titanate with high specific surface area was prepared from co-gel precursors through solvothermal method followed by supercritical drying. The samples were accumulated by BaTiO3 nanoparticles with excellent crystallinity. The BaTiO3 obtained at 60 °C exhibited a high BET surface area of 117 m2/g. The porosity reduced with the increasing solvothermal temperature. Raman spectra indicated that the solvothermal-synthesized BaTiO3 was composed by both cubic phase and tetragonal phase. The relations between dielectric properties and the porosity of the samples were also investigated. The introduction of pores reduced the dielectric constant obviously. The dielectric constant of the obtained sample increased with the decrease of the porosity.
Co-reporter:Yanyan Xu, Cuiqing Wang, Dairong Chen, Xiuling Jiao
Materials Letters 2010 Volume 64(Issue 3) pp:249-251
Publication Date(Web):15 February 2010
DOI:10.1016/j.matlet.2009.10.046
Nanostructured CuO film was prepared using glass or stainless steel slices as substrate via a simple ammonia-assisted solution route at 60 °C. The obtained CuO film was made up of well-crystallized nanosheets of 50–360 nm in thickness and 0.7–4.5 μm in width. The reaction time and the substrate have significant effects not only on the thickness, width, arrangement of the nanosheets but also on the morphology and the thickness of the films. The CuO film was characterized by SEM, TEM, XRD, IR, and Raman spectroscopy techniques.
Co-reporter:Zonglin Yang, Cong Cao, Fangfang Liu, Dairong Chen, Xiuling Jiao
Solid State Ionics 2010 Volume 181(15–16) pp:678-683
Publication Date(Web):3 June 2010
DOI:10.1016/j.ssi.2010.03.032
The nanostructured Li(Ni1/3Co1/3Mn1/3)O2/Li(Ni1/2Mn1/2)O2 fibers for use as lithium ion batteries were prepared by co-electrospinning combined with a sol–gel method. The core–shell Li(Ni1/3Co1/3Mn1/3)O2/Li(Ni1/2Mn1/2)O2 fibers show diameter of less than 5 μm and shell thickness of ca.300 nm, which are composed of the randomly arranged nanoparticles with size of 20–50 nm. The charge–discharge curves and cycle performance analyses indicated that the core–shell Li(Ni1/3Co1/3Mn1/3)O2/Li(Ni1/2Mn1/2)O2 fibers possess a high charge–discharge capacity, as well as good cyclical stability.
Co-reporter:Yang Tian;Juan Zhang;Ning Sui
Journal of Nanoparticle Research 2010 Volume 12( Issue 1) pp:161-168
Publication Date(Web):2010 January
DOI:10.1007/s11051-009-9590-5
A molten salt route to LaF3:Eu3+ nanoplate with tunable size was developed and the products were characterized by the X-ray diffraction (XRD), transmission electron microscopy (TEM), field-emission scanning electron microscopy (FE-SEM) and high-resolution TEM (HR-TEM). It is found that the nanoplates with different sizes (ca. 46, 20, and 12 nm) could be obtained when the molar ratio of the reagents NH4F and La(NO3)3 · 6H2O was adjusted. The possible formation process of reaction was discussed, and the reasonable mechanism of size controlling was also proposed. Furthermore, the luminescent properties of all the samples with different sizes and doping levels were investigated at room temperature.
Co-reporter:Yanyan Xu, Dairong Chen, Xiuling Jiao
Materials Letters 2009 Volume 63(Issue 21) pp:1859-1861
Publication Date(Web):31 August 2009
DOI:10.1016/j.matlet.2009.05.063
Single-crystalline cuprous iodide semiconductor nanorods were fabricated via a facile and efficient room-temperature solution process by using polyacrylamide (PAM) as a structure-directing agent, followed by heat treatment at 180 °C. The diameter and length of the nanorods were estimated to be ca. 50 nm and ca. 1 μm, respectively. And the phase-transformation temperature and decomposition temperature of the as-prepared CuI nanorods were deduced from the DSC curve of the products, which decreased markedly compared with those of the bulk CuI material. Moreover, a possible growth mechanism of the CuI nanorods based on polymer-crystal interactions in a mild aqueous solution is proposed.
Co-reporter:Ning Sui, Yongzheng Duan, Xiuling Jiao and Dairong Chen
The Journal of Physical Chemistry C 2009 Volume 113(Issue 20) pp:8560-8565
Publication Date(Web):2017-2-22
DOI:10.1021/jp810452k
One-dimensional α- and β-MnO2 single-crystalline nanostructures were prepared by the molten salt route. Both α- and β-MnO2 nanostructures exhibited large aspect ratios with diameters of tens of nanometers and lengths as long as several micrometers. The formation mechanism of α/β-MnO2 nanostructures was proposed on the basis of the time-dependent experiments. In addition, the as-prepared α- and β-MnO2 nanostructures showed excellent catalytic performance in the Fenton-like reaction.
Co-reporter:Yanyan Xu ; Xiuling Jiao ;Dairong Chen
The Journal of Physical Chemistry C 2008 Volume 112(Issue 43) pp:16769-16773
Publication Date(Web):October 4, 2008
DOI:10.1021/jp8058933
Single-crystalline Cu2O hollow nanocubes were fabricated via a precursor hydrolysis process in aqueous solution at room temperature. The hollow structures were studied in detail using X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and high-magnification TEM (HR-TEM) techniques. During the synthesis process, the addition of NaOH and PEG was the key factor responsible for the formation of well-defined single-crystalline hollow structures. The nanocube size could be tuned between 50 and 200 nm by simply adjusting the reagent concentration and solvent. Furthermore, the size-dependent UV−vis adsorptions were characterized.
Co-reporter:Yuanxiang Gu, Dairong Chen, Xiuling Jiao and Fangfang Liu
Journal of Materials Chemistry A 2007 vol. 17(Issue 18) pp:1769-1776
Publication Date(Web):06 Feb 2007
DOI:10.1039/B614205B
Core–shell LiCoO2–MgO fibers for use as lithium ion batteries were prepared by co-electrospinning combined with a sol-gel process. The rheological properties and viscosity of the spinnable sols, and the pressures of the two sols during the co-electrospinning process were investigated, which had an obvious effect on the diameter and shell thickness of the core–shell fibers. The fibers had a highly crystalline LiCoO2 core composed of partially oriented nanocrystals and a poorly crystalline MgO shell. The cyclic voltammogram (CV) experiments indicated that the coaxial fiber electrode exhibited excellent reversibility, smaller impedance growth and preferable electrochemical properties with obvious improvement of cyclability compared to bare LiCoO2 fiber electrodes.
Co-reporter:Yuanxiang Gu, Dairong Chen, Xiuling Jiao and Fangfang Liu
Journal of Materials Chemistry A 2006 vol. 16(Issue 44) pp:4361-4366
Publication Date(Web):19 Sep 2006
DOI:10.1039/B608663B
1D arrays of Li1 + αV3O8 nanosheets have been fabricated by using electrospinning combined with the sol–gel process. The 1D nanostructures, depending on the anisotropic nature of the sol precursor, can be changed by adjusting the calcining temperature and electrospinning parameters. In the present work, the microstructure and formation mechanism of 1D nanostructures are studied, and their initial discharge capacity as the positive electrode material for lithium ion batteries is ca. 352 mAh g−1 and remains ca. 255 mAh g−1 after 40 cycles, which gives higher charge–discharge capacities and better cycle performance compared to the separated Li1 + αV3O8 nanosheets.
Co-reporter:Yuguo Xia, Bo Chen, Xiuling Jiao and Dairong Chen
Physical Chemistry Chemical Physics 2014 - vol. 16(Issue 12) pp:NaN5874-5874
Publication Date(Web):2014/02/03
DOI:10.1039/C4CP00090K
Cube-like basic aluminium sulfate crystals were prepared by a facile template-free hydrothermal strategy. The microstructures, morphologies and textural properties of as-synthesized material were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy. X-ray crystallography reveals that cubic basic aluminium sulfate possesses a single crystal nature. Chemical formation mechanism studies of sulfuric acid with γ-AlOOH were performed using a combined experimental and computational approach. Time dependent experiments reveal that formation of basic aluminium sulfate is based on the dissolution–recrystallization process, and the source of Al3+ is from the dissolution of γ-AlOOH at high H+ concentration. Moreover, the quantum mechanical calculations reveal that dramatic structural changes occurred in the (100) plane at high H+ concentration, which is inferred to be the initiation of the source of Al3+. Meanwhile, surface energy calculations can well explain the exposed plane of basic aluminium sulfate microcubes, which are consistent with the XRD results. Besides, equations to quantitatively describe the relationship between the molar amount of H+ and the final phase are proposed, which has been confirmed by experimental results.
Co-reporter:Yuguo Xia, Li Zhang, Xiuling Jiao and Dairong Chen
Physical Chemistry Chemical Physics 2013 - vol. 15(Issue 41) pp:NaN18299-18299
Publication Date(Web):2013/09/09
DOI:10.1039/C3CP53110D
The investigation of the metal oxide/inorganic ion interface at the atomic level represents a fundamental issue for the understanding of chemical and physical processes involved in several fields such as catalysis, adsorption, directed synthesis and the mechanistic study of crystal growth. In this paper, a combined hydrothermal synthesis and computational approach based on DFT theory is adopted to investigate the effects of sulfate ions on the final morphology of γ-AlOOH. The quantum mechanical calculations reveal that the sulfate ions interact with γ-AlOOH facets through surface hydroxyls and act as a morphology-directing agent. The adsorption type and chemical bonds between the sulfate ion and γ-AlOOH are discussed. The formation of nanosheets and nanorods of γ-AlOOH is controlled by thermodynamic factors. Moreover, the HR-TEM images reveal the growth directions and exposed planes of boehmite, indicating an oriented-aggregation process which is consistent with the DFT calculations. Overall, all the morphologies of boehmite suggested by the calculations are confirmed by experimental results.
Co-reporter:Jian Zhang, Yuguo Xia, Li Zhang, Dairong Chen and Xiuling Jiao
Physical Chemistry Chemical Physics 2015 - vol. 17(Issue 41) pp:NaN27398-27398
Publication Date(Web):2015/09/16
DOI:10.1039/C5CP03859F
In-depth understanding of the sol–gel process plays an essential role in guiding the preparation of new materials. Herein, the effects of different inorganic acids (HCl, HNO3 and H2SO4) and divalent hydrated metal cations (Mg2+, Ca2+, Co2+, Ni2+) on γ-AlOOH sol–gel process were studied based on experiments and density functional theory (DFT) calculations. In these experiments, the sol originating from the γ-AlOOH suspension was formed only with the addition of HCl and HNO3, but not with H2SO4. Furthermore, the DFT calculations showed that the strong adsorption of HSO4− on the surface of the γ-AlOOH particles, and the hydrogen in HSO4− pointing towards the solvent lead to an unstable configuration of electric double layer (EDL). In the experiment, the gelation time sequence of γ-AlOOH sol obtained by adding metal ions changed when the ionic strength was equal to or greater than 0.198 mol kg−1. The DFT calculations demonstrated that the adsorption energy of hydrated metal ions on the γ-AlOOH surface can actually make a difference in the sol–gel process.
Co-reporter:Yuanxiang Gu, Dairong Chen, Xiuling Jiao and Fangfang Liu
Journal of Materials Chemistry A 2007 - vol. 17(Issue 18) pp:NaN1776-1776
Publication Date(Web):2007/02/06
DOI:10.1039/B614205B
Core–shell LiCoO2–MgO fibers for use as lithium ion batteries were prepared by co-electrospinning combined with a sol-gel process. The rheological properties and viscosity of the spinnable sols, and the pressures of the two sols during the co-electrospinning process were investigated, which had an obvious effect on the diameter and shell thickness of the core–shell fibers. The fibers had a highly crystalline LiCoO2 core composed of partially oriented nanocrystals and a poorly crystalline MgO shell. The cyclic voltammogram (CV) experiments indicated that the coaxial fiber electrode exhibited excellent reversibility, smaller impedance growth and preferable electrochemical properties with obvious improvement of cyclability compared to bare LiCoO2 fiber electrodes.
Co-reporter:Yan Wang, Wei Li, Xiuling Jiao and Dairong Chen
Journal of Materials Chemistry A 2013 - vol. 1(Issue 36) pp:NaN10726-10726
Publication Date(Web):2013/06/26
DOI:10.1039/C3TA10955K
Mesoporous alumina fibers were successfully synthesized via an electrospinning technique combined with a sol–gel method in the presence of a triblock copolymer as a structure directing agent. The amorphous alumina fibers derived from the electrospun xerogel fibers after calcinations at 450 °C and the γ-Al2O3 fibers obtained after the xerogel fibers were calcined at 700 °C exhibit uniform mesopores with fiber diameters of 130–200 nm, and BET surface areas up to 264.1 m2 g−1 and 242.6 m2 g−1, respectively. After the xerogel fibers were calcined at 1100 °C, with the transformation from γ-Al2O3 to α-Al2O3, a significant grain growth occurs and the mesopores disappear. Further investigation indicates that the γ-Al2O3 fibers have good adsorption properties toward Congo red with a maximum adsorption capacity of 781.25 mg g−1 for the sample obtained at 700 °C. In addition, the fibers show a good stability in acidic conditions and during a reuse process, which indicates their potential applications in adsorption as well as related areas, such as catalysis and catalyst supports.
Co-reporter:Yan Wang, Wei Li, Yuguo Xia, Xiuling Jiao and Dairong Chen
Journal of Materials Chemistry A 2014 - vol. 2(Issue 36) pp:NaN15131-15131
Publication Date(Web):2014/07/22
DOI:10.1039/C4TA01770F
Novel self-standing γ-alumina fibrous membranes with good flexibility have been successfully fabricated for the first time using an electrospinning technique. The γ-alumina membranes were composed of randomly arranged nanofibers with a high aspect ratio and small diameter (ca. 230 nm). The γ-alumina membranes show high tensile strength (2.98 MPa) and thermal stability (up to 900 °C), which favor their applications in high temperature conditions. Furthermore, the γ-alumina membranes exhibit good filtration performance for 300 nm dioctyl phthalate fine particulate gas filtration. The filtration efficiency is 99.848% and the pressure drop is 239.12 Pa for the membrane calcined at 700 °C with a basis weight of 9.28 g m−2; and the filtration efficiency could be over 99.97% when the basis weight is over 11.36 g m−2, suggesting that the γ-alumina fibrous membrane is a promising candidate for high temperature, fine particulate filtration applications. This work also provides a novel insight into the electrospinning of flexible self-standing inorganic membranes for applications in the separations field.
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