Co-reporter:Qingyong Tian, Weijing Yao, Wei Wu, Jun Liu, Zhaohui Wu, Li Liu, Zhigao Dai, and Changzhong Jiang
ACS Sustainable Chemistry & Engineering November 6, 2017 Volume 5(Issue 11) pp:10889-10889
Publication Date(Web):September 21, 2017
DOI:10.1021/acssuschemeng.7b02806
Efficiently reclaiming the utilization of solar light in a photocatalysis system remains very challenging. By integrating full advantage of upconversion material, plasmonic metals, and narrow bandgap semiconductors, β-NaYF4:18%Yb3+ and 2%Tm3+@SnO2@Ag nanoparticles (denoted as NaYF4@SnO2@Ag NPs) are designed and successfully synthesized as a wide-spectral (UV–vis-NIR) responsive upconversion and plasmonic-enhanced photocatalyst. The as-obtained NaYF4@SnO2@Ag NPs present broadband optical absorption dimension, excellent photocatalytic efficiency, and good stability for the degradation of organic dyes. The enhanced photocatalytic performance of NaYF4@SnO2@Ag NPs can be attributed to the synergistic effects of the components composed in this core/shell architecture that result in higher photocarriers yield and favor the efficient transfer of photocarriers and energy. This work gives insight to guidance of fabricating efficient, multicomponent upconversion catalysts and proposes a potential in the field of high-efficiency environmental and energy-related applications.Keywords: Core/shell structure; Energy transfer; FDTD calculation; Plasmonic photocatalyst; Upconversion materials;
Co-reporter:Xingang Zhang, Shuyao Si, Xiaolei Zhang, Wei Wu, Xiangheng Xiao, and Changzhong Jiang
ACS Applied Materials & Interfaces November 22, 2017 Volume 9(Issue 46) pp:40726-40726
Publication Date(Web):October 31, 2017
DOI:10.1021/acsami.7b13708
The ability to enhance the heat resistance of noble metals is vital to many industrial and academic applications. Because of its exceptional thermal properties, graphene was used to enhance the thermal stability of noble metals. Monolayer graphene-covered noble metal triangular nanoarrays (TNAs) showed excellent heat resistance, which could maintain their original triangular nanoarrays at high temperatures, whereas bare noble metal TNAs all agglomerate into spherical nanoparticles. On the basis of this mechanism, we obtained a universal recyclable surface-enhanced Raman scattering (SERS) substrate; after 16 cycles, the SERS substrate still worked well. The improvement of the heat resistance of noble metals by graphene has a great significance to the working reliability and service life of electronic devices and the single-use problem of traditional SERS substrates.Keywords: graphene; noble metal triangular nanoarrays; recyclable; surface-enhanced Raman scattering; thermal stability;
Co-reporter:Xudong Zheng, Feng Ren, Shunping Zhang, Xiaolei Zhang, Hengyi Wu, Xingang Zhang, Zhuo Xing, Wenjing Qin, Yong Liu, and Changzhong Jiang
ACS Applied Materials & Interfaces April 26, 2017 Volume 9(Issue 16) pp:14534-14534
Publication Date(Web):April 11, 2017
DOI:10.1021/acsami.7b03839
Surface-enhanced Raman spectroscopy (SERS) is a versatile and powerful spectroscopic technique for substance analysis and detection. So far, the highest detection sensitivities have been realized on noble nanostructure substrates, which, however, are costly, unstable, and non-biocompatible. While semiconductor substrates could in principle be used, existing realizations have either resulted in substrates with low sensitivities or used methods that have poor technical control. Here we report a general and versatile method, based on ion irradiation and vacuum annealing, for fabricating large-scale reduced semiconducting oxide SERS substrates with high sensitivities. The SERS enhancement mainly stems from oxygen vacancy-associated electronic states created by the ion irradiation of sample; these states enhance the charge-transfer (CT) mechanism between the oxide substrate and the adsorbed molecules and thus significantly magnify SERS signals. The improved carrier mobility by vacuum annealing and the introduction of impurity energy levels and nanostructures enhances further the CT efficiency. A detection limit as low as 5 × 10–8 M was achieved; this is the highest sensitivity among the reported semiconductors, and it even compares to noble metals without the aid of “hot spots”. The method is general—we demonstrate it on WO3, ZnO, and TiO2 substrates using Ar+ and N+ ion beam irradiation—and broadly applicable to produce noble-metal-free SERS substrates with high sensitivities.Keywords: charge transfer; ion irradiation; oxygen vacancy; semiconducting oxide; surface-enhanced Raman scattering;
Co-reporter:Qingyong Tian;Weijing Yao;Zhaohui Wu;Jun Liu;Li Liu;Wei Wu
Journal of Materials Chemistry A 2017 vol. 5(Issue 45) pp:23566-23576
Publication Date(Web):2017/11/21
DOI:10.1039/C7TA07529D
The development of efficient full-spectrum-activated photocatalysts has become a research topic of intense interest in environmental remediation or solar energy conversion applications. Herein, newly Z-scheme UV-vis-NIR-activated photocatalysts consisting of β-NaYF4:18% Yb3+, 2% Er3+@TiO2–Ag6Si2O7 (denoted as NaYF4@T–ASO) were designed and used as full-spectrum response photocatalysts. For tailoring NaYF4@T–ASO, the size of in situ deposited ASO nanoparticles on the surface of NaYF4@T microplates was determined by the pumping rate of the AgNO3 precursor, which played indirect roles in the photocatalytic activity with different carrier migration distances. Especially, NaYF4@T–ASO (S10) with the smallest and well distributed ASO nanoparticles showed superior photocatalytic activity than the commercial P25 TiO2 by 15 fold under the stimulated solar light irradiation. The enhanced photocatalytic performance of NaYF4@T–ASO could be ascribed to the synergic effect of the upconversion material and the direct Z-scheme heterojunction formed between TiO2/ASO, where the Z-scheme heterojunction induced efficient separation of photogenerated carriers and highly oxidative species (h+ and ˙O2−). Alternative mechanisms of carriers and energy transfer under various light sources have been proposed and discussed in detail.
Co-reporter:Qingyong Tian;Wei Wu;Jun Liu;Zhaohui Wu;Weijing Yao;Jin Ding
Dalton Transactions 2017 vol. 46(Issue 9) pp:2770-2777
Publication Date(Web):2017/02/28
DOI:10.1039/C7DT00018A
The development of photocatalysts with superior photoactivity and stability for the degradation of organic dyes is very important for environmental remediation. In this study, we have presented a multidimensional (1D and 2D) structured CdS/ZnIn2S4/RGO photocatalyst with superior photocatalytic performance. The CdS/ZnIn2S4 helical dimensional heterostructures (DHS) were prepared via a facile solvothermal synthesis method to facilitate the epitaxial growth of 2D ZnIn2S4 nanosheets on 1D CdS nanowires. Ultrathin 2D ZnIn2S4 nanosheets have grown uniformly and perpendicular to the surface of 1D CdS nanowires. The as-obtained 1D/2D CdS/ZnIn2S4 helical DHS show good photocatalytic properties for malachite green (MG). Subsequently, 2D reduced graphene oxide (RGO) was introduced into the 1D/2D CdS/ZnIn2S4 helical DHS as a co-catalyst. The photoactivity and stability of the CdS/ZnIn2S4/RGO composites are significantly improved after 6 cycles. The enhanced photoactivity can be attributed to the high surface area of RGO, the improved adsorption of organic dyes and the efficient spatial separation of photo-induced charge carriers. The transfer of photo-generated electrons from the interface of CdS and ZnIn2S4 to RGO also restricted the photocorrosion of metal sulfide, suggesting an improved stability of the reused CdS/ZnIn2S4/RGO composited photocatalyst.
Co-reporter:Yichao Liu, Shaohua Shen, Feng Ren, Jianan Chen, Yanming Fu, Xudong Zheng, Guangxu Cai, Zhuo Xing, Hengyi Wu and Changzhong Jiang
Nanoscale 2016 vol. 8(Issue 20) pp:10642-10648
Publication Date(Web):23 Nov 2015
DOI:10.1039/C5NR05594F
Porous photoelectrodes show high efficiency in hydrogen production by water splitting. However, fabrication of porous nanorods is usually difficult. Here, we report a simple approach to fabricate a kind of novel porous rutile titanium dioxide nanorod array by an advanced ion implantation method using multiple-energy helium ion implantation and subsequent annealing. The porous nanostructure enhances the photoelectrochemical performance of the titanium dioxide nanorod array photoelectrodes under Uv-visible light illumination, where the highest photocurrent density was relatively about 10 times higher than that of the pristine titanium dioxide nanorod array. The formation of nanocavities mainly contributes to the enhancement of the photocurrent density by trapping holes inside to separate the charge carriers. The study demonstrates that ion implantation could be an effective approach to develop novel porous nanostructural photoelectrodes for the application of hydrogen production.
Co-reporter:Lingling Sun, Wei Wu, Qingyong Tian, Mei Lei, Jun Liu, Xiangheng Xiao, Xudong Zheng, Feng Ren, and Changzhong Jiang
ACS Sustainable Chemistry & Engineering 2016 Volume 4(Issue 3) pp:1521
Publication Date(Web):December 14, 2015
DOI:10.1021/acssuschemeng.5b01473
In this work, the novel dumbbell-like α-Fe2O3/Ag/AgX (X = Cl, Br, I) heterostructures were successfully synthesized via an in situ oxidation reaction and self-assembly process by using the α-Fe2O3/Ag core–shell nanoparticles (NPs). The as-obtained dumbbell-like α-Fe2O3/Ag/AgX heterostructure contains an individual spindle-like α-Fe2O3 nanoparticle and a single near-spherical Ag/AgX nanoparticle. The morphology, microstructure, component and optical property of as-synthesized α-Fe2O3/Ag/AgX heterostructures were characterized by various analytical techniques. The great changing of morphology and component in such synthesis route make great effect on the final photocatalytic performance. The dumbbell-like α-Fe2O3/Ag/AgX heterostructures exhibit excellent photocatalytic activity for the degradation of RhB dye under simulated sunlight irradiation. In particular, the α-Fe2O3/Ag/AgCl can completely degrade RhB molecules within only 20 min under simulated sunlight irradiation, which is superior to the pure α-Fe2O3, α-Fe2O3/Ag NPs, and commercial P25. The enhanced activity is attributed to the efficient interfacial charge rectification and faster carrier migration in the α-Fe2O3/Ag/AgX heterostructures. Furthermore, the degradation rate of as-synthesized dumbbell-like α-Fe2O3/Ag/AgX (X = Cl, Br, I) heterostructures follows this order: α-Fe2O3/Ag/AgCl > α-Fe2O3/Ag/AgBr > α-Fe2O3/Ag/AgI. The results can be owing to that the oxidation capability of Cl0 is stronger than Br0 and I0. This unique synthetic work can provide physical insight into prepare novel nanomaterials with special structures and properties, which can apply in photocatalysis, photosplitting of water and solar cell, etc.Keywords: Dumbbell-like structure; Noble metal; Photocatalytic activity; Silver halides
Co-reporter:Jun Liu, Wei Wu, Qingyong Tian, Zhigao Dai, Zhaohui Wu, Xiangheng Xiao and Changzhong Jiang
Dalton Transactions 2016 vol. 45(Issue 32) pp:12745-12755
Publication Date(Web):13 Jul 2016
DOI:10.1039/C6DT02499H
Coupling two different semiconductors to form composite photocatalysts is the most significant method for environmental remediation. In this regard, tube-like α-Fe2O3/Ag6Si2O7 heterostructures are synthesized via anchoring p-type Ag6Si2O7 nanoparticles (NPs) on the surface of n-type α-Fe2O3 short nanotubes (SNTs) by conventional wet-chemical routes. α-Fe2O3 SNTs are firstly fabricated by a hydrothermal method with the assistance of dihydrogen phosphate and sulphate. Then, Ag6Si2O7 NPs are anchored on α-Fe2O3 SNTs by an in situ deposition method, and the α-Fe2O3/Ag6Si2O7 p–n heterostructures are finally obtained. The morphologies, crystal structure, photocatalytic performance and photocurrent properties of as-synthesized α-Fe2O3/Ag6Si2O7 heterostructures are investigated. Six organic dyes are used for determining the high-efficiency Z-scheme photocatalytic activities of the as-obtained photocatalysts under ultraviolet and visible light (mercury lamp, 300 W). Compared with pure α-Fe2O3 SNTs, the photocurrent intensity of the α-Fe2O3/Ag6Si2O7 heterostructures is improved 62 times. The enhanced significant photocatalytic performance of α-Fe2O3/Ag6Si2O7 heterostructures could be attributed to charge transfer between Ag6Si2O7 NPs and the charge separation between Ag6Si2O7 NPs and α-Fe2O3 SNTs. These composite heterostructures are proposed to be an example for the preparation of other composite silicate photocatalysts for practical application in environmental remediation issues.
Co-reporter:Lingling Sun, Wei Wu, Qingyong Tian, Mei Lei, Zhigao Dai, Xiangheng Xiao, Feng Ren, Changzhong Jiang
Materials Science in Semiconductor Processing 2016 Volume 41() pp:411-419
Publication Date(Web):January 2016
DOI:10.1016/j.mssp.2015.10.015
The p–n heterojunction is an effective structure to suppress the recombination of photogenerated charge carriers due to the built-in internal electric field. Herein, we successfully synthesize a spindle-like α-Fe2O3/Bi2O3 core–shell heterostructure, in which α-Fe2O3 is an n-type semiconductor and Bi2O3 is a p-type semiconductor. In comparison with pure α-Fe2O3 seeds, the α-Fe2O3/Bi2O3p–n heterojunction photocatalyst exhibits tremendous photocatalytic performance on the degradation of Rhodamine B (RhB) under illumination of visible light. In addition, we insert an interlayer between p–n heterostructure, similar to p–i–n heterostructure. The silicon oxide and carbon are selected as the interlayer due to its different conductivity. The as-obtained α-Fe2O3/C/Bi2O3 exhibits higher degradation rate than α-Fe2O3/SiO2/Bi2O3. The reason is attributed to the mesoporous structure of carbon layer and its high conductivity so that the photogenerated electrons can be easily transferred from the conduction band of α-Fe2O3 to the conduction band of Bi2O3 thereby promoting an effective separation of photogenerated electrons and holes. However, the introduction of interlayer reduces the photocatalytic activity due to the alteration of internal built-in electric field in the heterojunction. We envision that these results have potential applications for designing the heterostructural photocatalysts.The spindle-like α-Fe2O3/Bi2O3 core–shell p–n heterojunction has been prepared and it exhibits excellent photocatalytic performance for the degradation of Rhodamine B (RhB) under illumination of visible light. To further understand the mechanism of this p–n heterostructure, carbon and silica are introduced as an interlayer between the p-type and n-type semiconductor.
Co-reporter:Gongming Wang, Xiangheng Xiao, Wenqing Li, Zhaoyang Lin, Zipeng Zhao, Chi Chen, Chen Wang, Yongjia Li, Xiaoqing Huang, Ling Miao, Changzhong Jiang, Yu Huang, and Xiangfeng Duan
Nano Letters 2015 Volume 15(Issue 7) pp:4692-4698
Publication Date(Web):June 8, 2015
DOI:10.1021/acs.nanolett.5b01547
Titanium oxide (TiO2) represents one of most widely studied materials for photoelectrochemical (PEC) water splitting but is severely limited by its poor efficiency in the visible light range. Here, we report a significant enhancement of visible light photoactivity in nitrogen-implanted TiO2 (N-TiO2) nanowire arrays. Our systematic studies show that a post-implantation thermal annealing treatment can selectively enrich the substitutional nitrogen dopants, which is essential for activating the nitrogen implanted TiO2 to achieve greatly enhanced visible light photoactivity. An incident photon to electron conversion efficiency (IPCE) of ∼10% is achieved at 450 nm in N-TiO2 without any other cocatalyst, far exceeding that in pristine TiO2 nanowires (∼0.2%). The integration of oxygen evolution reaction (OER) cocatalyst with N-TiO2 can further increase the IPCE at 450 nm to ∼17% and deliver an unprecedented overall photocurrent density of 1.9 mA/cm2, by integrating the IPCE spectrum with standard AM 1.5G solar spectrum. Systematic photoelectrochemical and electrochemical studies demonstrated that the enhanced PEC performance can be attributed to the significantly improved visible light absorption and more efficient charge separation. Our studies demonstrate the implantation approach can be used to reliably dope TiO2 to achieve the best performed N-TiO2 photoelectrodes to date and may be extended to fundamentally modify other semiconductor materials for PEC water splitting.
Co-reporter:Jun Liu, Shuanglei Yang, Wei Wu, Qingyong Tian, Shuyuan Cui, Zhigao Dai, Feng Ren, Xiangheng Xiao, and Changzhong Jiang
ACS Sustainable Chemistry & Engineering 2015 Volume 3(Issue 11) pp:2975
Publication Date(Web):September 27, 2015
DOI:10.1021/acssuschemeng.5b00956
The 3D flowerlike α-Fe2O3@TiO2 core–shell nanocrystals with thorhombic, cubic, and discal morphologies are synthesized for photocatalytic application. α-Fe2O3 nanocrystals were prepared via a Cu2+, Zn2+, and Al3+ ion-mediated hydrothermal route. The α-Fe2O3@TiO2 core–shell nanocrystals are obtained via a hydrothermal and annealing process. The shape-dependent photocatalytic activities of these as-obtained α-Fe2O3@TiO2 core–shell nanocrystals are measured. The results reveal that the discal α-Fe2O3@TiO2 nanocrystals exhibit the best photocatalytic activity relative to the other two core–shell nanocrystals because the discal α-Fe2O3 nanocrystals possess more rough surface and surface defects. The fast interfacial charge-transfer process and the wide spectral response could be the driving force for the enhanced photocatalytic performance. These core–shell architectures provide a positive example for synthesis of novel composite nanomaterial.Keywords: Core−shell structure; Heterostructures; Iron oxide; Photocatalyst; Titanium dioxide;
Co-reporter:Lingling Sun, Wei Wu, Shuanglei Yang, Juan Zhou, Mengqing Hong, Xiangheng Xiao, Feng Ren, and Changzhong Jiang
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 2) pp:1113
Publication Date(Web):December 26, 2013
DOI:10.1021/am404700h
Our study reports a novel iron oxide/noble metal/semiconductor ternary multilayer hybrid structure that was synthesized through template synthesis and layer-by-layer deposition. Three different morphologies of α-Fe2O3/Ag/SiO2/SnO2 hybrid architectures were obtained with different thicknesses of the SiO2 interlayer which was introduced for tailoring and controlling the coupling of noble metal Ag nanoparticles (NPs) with the SnO2 semiconductor. The resulting samples were characterized in terms of morphology, composition, and optical property by various analytical techniques. The as-obtained α-Fe2O3/Ag/SiO2/SnO2 nanocomposites exhibit enhanced visible light or UV photocatalytic abilities, remarkably superior to commercial pure SnO2 products, bare α-Fe2O3 seeds, and α-Fe2O3/SnO2 nanocomposites. Moreover, the sample of α-Fe2O3/Ag/SiO2/SnO2 also exhibits good chemical stability and recyclability because it has higher photocatalytic activity even after eight cycles. The origin of enhanced photocatalytic activity on the multilayer core–shell α-Fe2O3/Ag/SiO2/SnO2 nanocomposites was primarily ascribed to the coupling between noble metal Ag and the two semiconductors Fe2O3 and SnO2, which are proven to be applied in recyclable photocatalysis.Keywords: heterostructures; iron oxide; noble metal; photocatalytic activity; SiO2 interlayer;
Co-reporter:Wei Wu, Shuanglei Yang, Jun Pan, Lingling Sun, Juan Zhou, Zhigao Dai, Xiangheng Xiao, Hongbo Zhang and Changzhong Jiang
CrystEngComm 2014 vol. 16(Issue 25) pp:5566-5572
Publication Date(Web):26 Mar 2014
DOI:10.1039/C4CE00048J
A facile and effective hydrothermal process for the controllable synthesis of uniform single-crystalline hematite (α-Fe2O3) nanoparticles with different shapes is presented. The morphology of the α-Fe2O3 products can be controlled through simply adjusting the metal ions additive. The effects of the different metal ions (atomic number from 25–30) on the size and morphology of the products were investigated. The cubic and thorhombic α-Fe2O3 particles can be generated by adding zinc ions and copper ions to the reaction mixture, respectively. For providing some insight into the correlation between the morphology and physicochemical properties, the magnetic properties of the as-obtained cubic and thorhombic α-Fe2O3 products were investigated. Interestingly, the cubic α-Fe2O3 products exhibited a superparamagnetic properties at T = 300 K. In contrast, the thorhombic α-Fe2O3 products displayed ferromagnetic and low-temperature phase transition behaviours at room temperature. The fundamental understanding of crystal-phase and morphology-tunable nanostructures that are enclosed by shape-dependent magnetic properties is expected to direct the design and development of highly efficient magnetic nanomaterials.
Co-reporter:Wei Wu, Shuanglei Yang, Shaofeng Zhang, Hongbo Zhang, Changzhong Jiang
Journal of Colloid and Interface Science 2014 Volume 427() pp:15-19
Publication Date(Web):1 August 2014
DOI:10.1016/j.jcis.2013.10.064
•We present a facile approach to the gram-scale production of the carbon–core/Ag–shell (C@Ag) nanoparticles.•A controllable Ag shell thickness from 10 to 40 nm can be tailored by simple adjustments of repeat coating times.•The conductive ink of C@Ag nanoparticles was printed on paper by screen printing.•The conductivity of printing antenna depends on the Ag coating thickness.The large-scale synthesis and characterization of carbon–core/Ag–shell (C@Ag) nanoparticles by the successive reduction of silver ammonia are described. The resultant C@Ag nanoparticles had a mean core diameter of 360 nm and a controllable shell thickness from 10 to 40 nm by simple adjustments of repeat coating times. Various analysis techniques confirmed that the carbon cores were fully covered by Ag nanoshells. The results also show that C/Ag composite nanomaterials-based conductive inks, which can be easily produced on a large scale and possess outstanding electronic properties, have great potential for the convenient fabrication of flexible and low-cost carbon-based electronic devices and replace the traditional pure silver paste, by using a simple screen printing technique.Graphical abstract
Co-reporter:Hongxiu Zhang, Feng Ren, Mengqing Hong, Xiangheng Xiao, Guangxu Cai, Changzhong Jiang
Journal of Materials Science & Technology 2014 Volume 30(Issue 10) pp:1012-1019
Publication Date(Web):October 2014
DOI:10.1016/j.jmst.2014.01.006
V/Ag multilayers with different periodic thicknesses were fabricated by magnetron sputtering deposition. The columnar structure and the orientation relationship of the multilayers were investigated by transmission electron microscopy, high resolution transmission electron microscopy, selected-area electron diffraction and X-ray diffraction. It was found that the multilayered structure became flatter as increasing individual layer thickness from 2 to 6 nm, and then became waved as the individual layer thickness increases to 8 nm. At the beginning of the growth, the morphology of the multilayers with small periodic thickness was influenced mainly by thermodynamic instabilities, and the morphology of the multilayers with larger periodic thickness was mainly influenced mainly by the columnar growth of V. When the waved interfaces were formed, the continuum growth of the multilayers was also influenced by the shadowing effect and the finite atomic size effect. All of these factors resulted in the columnar structure of the multilayers. Multilayers with small periodic thickness presented strong orientation relationship. Nano-hardness tests indicated that multilayers with flat sublayer morphology and clear interfaces exhibited larger hardness.
Co-reporter:Junfeng Zheng ; Zhigao Dai ; Fei Mei ; Xiangheng Xiao ; Lei Liao ; Wei Wu ; Xinyue Zhao ; Jianjian Ying ; Feng Ren
The Journal of Physical Chemistry C 2014 Volume 118(Issue 35) pp:20521-20528
Publication Date(Web):August 12, 2014
DOI:10.1021/jp504803d
Interest in monolayer binary colloidal crystals (bCCs) has long been motivated by their wide applications. Large-area various monolayer bCC patterns are self-assembled in air–water interface and reveal that the structure of closely packed large polystyrene (PS) colloidal spheres is vital to the formation of bCCs. Small spheres may have very limited influence on the final close-packed structure of large spheres; therefore, the periodically ordered bCC patterns can be designed by choosing large colloidal spheres with the needed size. After oxygen plasma treatment, various controllable morphologies of nanoparticles can be achieved by the etched spheres acting as a template during the metal deposition. On the basis of the complex bCC patterns and subsequent oxygen plasma processing, this work points to a new method of designing the dimension and separation of nontraditional evaporated structures, including dot, strip, and block, which demonstrate fine structure enhanced performance. The experimental results are further supported by theoretical calculations.
Co-reporter:Juan Zhou, Feng Ren, Shaofeng Zhang, Wei Wu, Xiangheng Xiao, Ying Liu and Changzhong Jiang
Journal of Materials Chemistry A 2013 vol. 1(Issue 42) pp:13128-13138
Publication Date(Web):29 Aug 2013
DOI:10.1039/C3TA12540H
Tailorable synthesis of plasmon enhanced catalysts with high solar-light harvesting and energy-conversion efficiency has attracted wide interest due to its scientific and technological importance. In this paper, novel SiO2–Ag–SiO2–TiO2 multi-shell photocatalysts with wide-spectral-response were systematically designed and controllably synthesized, where the SiO2 spheres were used as the cores, and the SiO2 interlayers coated on the Ag nanoparticle (NP) shells were used to separate the Ag from the TiO2 shell. The structures of the SiO2–Ag–SiO2–TiO2 multi-shell photocatalysts can be tailored by changing the thickness of SiO2 interlayers from 1 to 2, 5, 8, 12, and 20 nm, while the anatase N-doped TiO2 shells with visible light response are maintained at a thickness of 20 nm. The photocatalytic activity tests show that the enhanced photocatalytic efficiency under both ultraviolet (UV) and visible light irradiation is related to the existence of Ag NP shells and the thickness of SiO2 interlayers. The complicated coupling mechanisms between TiO2 and a plasmon are systematically discussed, and a clear physical picture for the complicated coupling processes is presented. The main reasons for the enhancement of the photocatalytic activity of the SiO2–Ag–SiO2–TiO2 multi-shell structures are the localized surface plasmon resonance (LSPR) effect and scattering effect induced by Ag NPs.
Co-reporter:Wei Wu, Lei Liao, Shaofeng Zhang, Juan Zhou, Xiangheng Xiao, Feng Ren, Lingling Sun, Zhigao Dai and Changzhong Jiang
Nanoscale 2013 vol. 5(Issue 12) pp:5628-5636
Publication Date(Web):23 Apr 2013
DOI:10.1039/C3NR00985H
We present an innovative approach to the production of sub-100 nm hollow Au–SnO2 hybrid nanospheres, employing a low-cost, surfactant-free and environmentally friendly solution-based route. The hollow hybrid nanostructures were synthesized using a seed-mediated hydrothermal method, which can be divided into two stages: (1) formation of multicore–shell Au@SnO2 nanoparticles (NPs) and (2) thermal diffusion and ripening to form hollow Au–SnO2 hybrid NPs. The morphology, optical properties and formation mechanism were determined by a collection of joint techniques. Photocatalytic degradation of Rhodamine B (RhB) in the liquid phase served as a probe reaction to evaluate the activity of the as-prepared hollow hybrid Au–SnO2 NPs under the irradiation of both visible light and ultraviolet light. Significantly, the as-obtained Au–SnO2 hybrid nanostructures exhibited enhanced visible light or UV photocatalytic abilities, remarkably superior to commercial pure SnO2 products and P25 TiO2, mainly owing to the effective electron hole separation at the SnO2–Au interfaces and strong localization of plasmonic near-fields effects.
Co-reporter:Shaofeng Zhang, Feng Ren, Wei Wu, Juan Zhou, Xiangheng Xiao, Lingling Sun, Ying Liu and Changzhong Jiang
Physical Chemistry Chemical Physics 2013 vol. 15(Issue 21) pp:8228-8236
Publication Date(Web):25 Mar 2013
DOI:10.1039/C3CP50925G
Composite materials containing different components with well-defined structures may cooperatively enhance their performance and extend their applications. In this work, core–shell γ-Fe2O3@SnO2 hollow nanoparticles (NPs) were synthesized by a low-cost and environmentally friendly seed-mediated hydrothermal method. Firstly, the γ-Fe2O3 hollow NPs were synthesized by a template-free method. Then they were used as the cores for the growth of SnO2 shells. The thickness of the shell can be simply tailored by controlling the reaction time. Various techniques, including SEM, XRD, TEM and HRTEM, were employed to investigate the morphology, structure and formation process of the special core–shell hollow structures. The combination of magnetic semiconductor (γ-Fe2O3) and wide band-gap semiconductor (SnO2) endowed them with great potential to be used as recyclable photocatalysts. Experiments on photo-degradation of Rhodamin B (RhB) dye in the presence of the samples showed that the hybrid structures possessed higher photocatalytic activities than the monomer structures of SnO2 and γ-Fe2O3 materials indicating a strong coupling enhancement effect between the wide and narrow band-gap semiconductors. Moreover, the gas sensing tests of the γ-Fe2O3@SnO2 hollow NPs revealed that the samples exhibited fast response and recovery rates, which enable them to be promising materials for gas sensors.
Co-reporter:J.J. Ying, X.H. Xiao, Z.G. Dai, W. Wu, W.Q. Li, F. Mei, G.X. Cai, F. Ren, C.Z. Jiang
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 2013 Volume 305() pp:29-32
Publication Date(Web):15 June 2013
DOI:10.1016/j.nimb.2013.04.044
Ion implantation provides a new synthesis route for graphene, and few-layered graphene synthesis by ion implantation has been reported. Here we show the synthesis of a single layer of high-quality graphene by Metal Vapor Vacuum Arc (MEVVA) source ion implantation. Polycrystalline nickel and copper thin films are implanted with MEVVA source carbon ions at 40 kV, followed by high-temperature thermal annealing and quenching. A Raman spectrum is applied to probe the quality and thickness of the prepared graphene. A single layer of high-quality graphene is grown on the nickel films, but not on the copper films. The growth mechanisms on the nickel and copper films are explained. MEVVA source ion implantation has been widely applied in industrial applications, demonstrating that this synthesis method can be generalized for industrial production.
Co-reporter:J.X. Xu, X.H. Xiao, A.L. Stepanov, F. Ren, F. Mei, W. Wu, G.X. Cai, C.Z. Jiang
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 2013 Volume 307() pp:373-376
Publication Date(Web):15 July 2013
DOI:10.1016/j.nimb.2013.01.011
Co-reporter:J.X. Xu, X.H. Xiao, F. Ren, X.D. Zhou, G.X. Cai, C.Z. Jiang
Vacuum 2013 Volume 89() pp:132-135
Publication Date(Web):March 2013
DOI:10.1016/j.vacuum.2012.02.045
(0001) α-Al2O3 single crystals (sapphire) were implanted with Zn+ ions at 60 keV to fluences of 1 × 1017 and 2 × 1017 ions/cm2; and were then annealed at different temperatures under oxygen ambient. Transmission electron microscopy and optical absorption spectra were used to investigate the formation of nanostructure and their thermal evolution. Our results clearly show that the evolution of ZnO nanoparticles depends strongly on the annealing temperature and time. Zn nanoparticles could be transformed into ZnO while for annealing at a temperature 600 °C. ZnO nanoparticles were formed in the Al2O3 when the sample was annealed at 700 °C for 1 h. However, while annealing at 700 °C for 2 h, ZnO single-crystal film was formed on the surface of Al2O3. Further increasing annealing temperature to 750 °C, polycrystalline ZnO nanoclusters were formed on the surface of the sample instead of ZnO film, and leaving nanovoids band in the implanted region for the sample implanted with higher fluence. All the Zn nanoparticles disappeared and transformed to ZnAl2O4 as the annealing temperature increased to 900 °C. Photoluminescence experiment was performed at room temperature to investigate the optical properties and the quality of formed ZnO on the surface of substrate.
Co-reporter:Wei Wu, Shaofeng Zhang, Xiangheng Xiao, Juan Zhou, Feng Ren, Lingling Sun, and Changzhong Jiang
ACS Applied Materials & Interfaces 2012 Volume 4(Issue 7) pp:3602
Publication Date(Web):June 12, 2012
DOI:10.1021/am300669a
Mesoporous spindlelike iron oxide/ZnO core–shell heterostructures are successfully fabricated by a low-cost, surfactant-free, and environmentally friendly seed-mediate strategy with the help of postannealing treatment. The material composition and stoichiometry, as well as these magnetic and optical properties, have been examined and verified by means of high-resolution transmission electron microscopy and X-ray diffraction, the thickness of ZnO layer can be simply tailored by the concentration of zinc precursor. Considering that both α-Fe2O3 and ZnO are good photocatalytic materials, we have investigated the photodegradation performances of the core–shell heterostructures using organic dyes Rhodamin B (RhB). It is interesting to find that the as-obtained iron oxides/ZnO core–shell heterostructures exhibited enhanced visible light or UV photocatalytic abilities, remarkably superior to the as-used α-Fe2O3 seeds and commercial TiO2 products (P25), mainly owing to the synergistic effect between the narrow and wide bandgap semiconductors and effective electron–hole separation at the interfaces of iron oxides/ZnO.Keywords: heterostructure; magnetic properties; mesoporous structure; photocatalyst; semiconductors;
Co-reporter:Juan Zhou, Feng Ren, Wei Wu, Shaofeng Zhang, Xiangheng Xiao, Jinxia Xu, Changzhong Jiang
Journal of Colloid and Interface Science 2012 Volume 387(Issue 1) pp:47-55
Publication Date(Web):1 December 2012
DOI:10.1016/j.jcis.2012.07.093
Polystyrene (PS)/gold (Au) core–shell nanocomposites with tunable size, high stability, and excellent catalytic activity have been synthesized by a facile method that combines the ionic self-assembly with the in situ reduction. The composition and stoichiometry, as well as its morphology and optical properties of these nanocomposites have been examined and verified by various characterization techniques. The size and the coverage of gold nanoparticles (NPs) can be simply tailored by changing the amount of 3-aminopropyltrimethoxysilane (APTES), the functionalization time, the protonation time, and the amount of chloroauric acid (HAuCl4). The continuous red shifts of the localized surface plasmon resonance absorption of the Au NPs on the PS spheres are observed. Importantly, the obtained Au NPs with controllable and uniform size on the surfaces of amino-functionalized PS spheres exhibit excellent size-dependent catalytic properties for the reduction of 4-nitrophenol (4-NP) by NaBH4.Graphical abstractHighlights► PS/Au composites are prepared by a facile self-assembly in situ reduction method. ► Au NP size can be conveniently tuned by controlling experimental parameters. ► PS/Au composites with high stability possess size-dependent catalytic activities.
Co-reporter:Tangchao Peng 彭堂超;Xiangheng Xiao;Feng Ren
Journal of Wuhan University of Technology-Mater. Sci. Ed. 2012 Volume 27( Issue 6) pp:1014-1019
Publication Date(Web):2012 December
DOI:10.1007/s11595-012-0591-3
TiO2 thin films were deposited on quartz substrates by DC reactive magnetron sputtering of a pure Ti target in Ar/O2 plasma at room temperature. The TiO2 films were annealed at different temperatures ranging from 300 to 800 °C in a tube furnace under flowing oxygen gas for half an hour each. The effect of annealing temperatures on the structure, optical properties, and morphologies were presented and discussed by using X-ray diffraction, optical absorption spectrum, and atomic force microscope. The films show the presence of diffraction peaks from the (101), (004), (200) and (105) lattice planes of the anatase TiO2 lattice. The direct band gap of the annealed films decreases with the increase of annealing temperature. While, the roughness of the films increases with the increases of annealing temperature, and some significant roughness changes of the TiO2 film surfaces were observed after the annealing temperature reached 800 °C. Moreover, the influences of annealing on the microstructures of the TiO2 film were investigated also by in situ observation in transmission electron microscope.
Co-reporter:Wei Wu, Shaofeng Zhang, Feng Ren, Xiangheng Xiao, Juan Zhou and Changzhong Jiang
Nanoscale 2011 vol. 3(Issue 11) pp:4676-4684
Publication Date(Web):23 Sep 2011
DOI:10.1039/C1NR10728C
Iron oxide/SnO2 magnetic semiconductor core–shell heterostructures with high purity were synthesized by a low-cost, surfactant-free and environmentally friendly hydrothermal strategy via a seed-mediated method. The morphology and structure of the hybrid nanostructures were characterized by means of high-resolution transmission electron microscopy and X-ray diffraction. The morphology evolution investigations reveal that the Kirkendall effect directs the diffusion and causes the formation of iron oxide/SnO2 quasi-hollow particles. Significantly, the as-obtained iron oxides/SnO2 core–shell heterostructures exhibited enhanced visible light or UV photocatalytic abilities, remarkably superior to as-used α-Fe2O3 seeds and commercial SnO2 products, mainly owing to the effective electron hole separation at the iron oxides/SnO2 interfaces.
Co-reporter:T.C. Peng, X.H. Xiao, X.Y. Han, X.D. Zhou, W. Wu, F. Ren, C.Z. Jiang
Applied Surface Science 2011 Volume 257(Issue 13) pp:5908-5912
Publication Date(Web):15 April 2011
DOI:10.1016/j.apsusc.2011.01.138
Abstract
Thin NiO films were deposited at 500 °C on n-type Si(1 1 1) by a DC reactive magnetron sputtering in a gas mixture of oxygen and argon. The ratio between the flow rates of oxygen and argon was respectively set at 1:4, 1:2, and 1:1. The dependence of structures and optical properties of NiO films were investigated using grazing incidence X-ray diffraction and spectroscopic ellipsometry in the spectral region of 1.5–5.0 eV. Ni-rich NiO films were obtained when the ratio between the flow rates of oxygen and argon was 1:4 and 1:2 in sputtering process. And when the ratio was 1:1, a relatively pure NiO film was formed. The partial pressure of oxygen could significantly influence the thickness and roughness of films. Refractive index n, extinction coefficient k, and direct gap energy and indirect gap energy of the NiO films were also subject to the influence of the partial pressure of oxygen.
Co-reporter:Dr. Wei Wu ;Shaofeng Zhang ;Juan Zhou ;Dr. Xiangheng Xiao ;Dr. Fen Ren ; Changzhong Jiang
Chemistry - A European Journal 2011 Volume 17( Issue 35) pp:9708-9719
Publication Date(Web):
DOI:10.1002/chem.201100694
Abstract
Controlled synthesis of low-dimensional materials, such as nanoparticles, nanorods, and hollow nanospheres, is vitally important for achieving desired properties and fabricating functional devices. We report a systematic investigation of the growth of low-dimensional sub-100 nm SnO2 hollow nanostructures by a mild template- and surfactant-free hydrothermal route, aiming to achieve precise control of morphology and size. The starting materials are potassium stannate and urea in an ethylene glycol (EG)/H2O system. We found the size of the SnO2 hollow nanospheres can be controlled by simply adjusting the urea concentration. Investigation of the mechanism of formation of the SnO2 hollow nanospheres revealed that reaction time, urea concentration, and reaction temperature make significant contributions to the growth of hollow nanospheres. On switching the solvent from EG/H2O to H2O or ethanol, the SnO2 nanostructures changed from nanospheres to ultrafine nanorods and nanoparticles. On the basis of reaction parameter dependent experiments, oriented self-assembly and subsequent evacuation through Ostwald ripening are proposed to explain the formation of hollow nanostructures. Their size-dependent optical properties, including UV/Vis absorption spectra and room-temperature fluorescence spectra, were also studied. Moreover, the studies on the photocatalytic property demonstrate that the fabricated hollow structures have slightly enhanced photocatalytic degradation activity for rhodamine B when exposed to mercury light irradiation compared to solid SnO2 nanospheres under the same conditions. The synthesized tin oxide nanoparticles display high photocatalytic efficiency and have potential applications for cleaning polluted water in the textile industry.
Co-reporter:Wei Wu Dr.;Xiangheng Xiao Dr.;Tangchao Peng Dr.
Chemistry – An Asian Journal 2010 Volume 5( Issue 2) pp:315-321
Publication Date(Web):
DOI:10.1002/asia.200900378
Abstract
Connected zinc oxide (ZnO) nanoparticles are successfully synthesized by a simple solution-based chemical route that uses evaporation and concentration technology. The influences of processing parameters, especially the evaporation and concentration time on the size and morphology of the nanoparticles, have been investigated by transmission electron microscopy (TEM) and high-resolution TEM (HRTEM). The structure and optical properties are systematically characterized by X-ray diffraction (XRD), UV/Vis spectrophotometery, and fluorescence spectroscopy (FL). It is found that the average diameter and morphology are strongly affected by the evaporation and concentration time. Additionally, the formation mechanism of the nanoparticles is also discussed. The studies revealed that the evaporation and concentration are important aggregation or nucleation processes for ZnO growth, which leads to the macro-differences in morphology. These results provide some insight into the growth mechanism of ZnO nanostructures. The synthetic strategy developed in this study may also be extended to the preparation of other nanomaterials and promising applications in various fields of nanotechnology.
Co-reporter:Wei Wu ; Xiangheng Xiao ; Shaofeng Zhang ; Juan Zhou ; Lixia Fan ; Feng Ren
The Journal of Physical Chemistry C 2010 Volume 114(Issue 39) pp:16092-16103
Publication Date(Web):September 7, 2010
DOI:10.1021/jp1010154
We present a facile approach to the production of magnetic iron oxide short nanotubes (SNTs) employing an anion-assisted hydrothermal route by simultaneously using phosphate and sulfate ions. The size, morphology, shape, and surface architecture control of the iron oxide SNTs are achieved by simple adjustments of ferric ions concentration without any surfactant assistance. The result of a formation mechanism investigation reveals that the ferric ions concentrations, the amount of anion additive, and the reaction time make significant contributions to SNT growth. The shape of the SNTs is mainly regulated by the adsorption of phosphate ions on faces parallel to the long dimension of elongated α-Fe2O3 nanoparticles (c axis) during nanocrystal growth, and the hollow structure is given by the preferential dissolution along the c axis due to the strong coordination of the sulfate ions. Moreover, the as-synthesized hematite (α-Fe2O3) SNTs can be converted to magnetite (Fe3O4) and maghemite (γ-Fe2O3) ferromagnetic SNTs by a reducing atmosphere annealing process while preserving the same morphology. The structures and magnetic properties of these iron oxide SNTs were characterized by various analytical techniques.
Co-reporter:W Wu;XH Xiao;SF Zhang;TC Peng;J Zhou;F Ren;CZ Jiang
Nanoscale Research Letters 2010 Volume 5( Issue 9) pp:
Publication Date(Web):2010 September
DOI:10.1007/s11671-010-9664-4
We report a rational synthesis of maghemite (γ-Fe2O3) short-nanotubes (SNTs) by a convenient hydrothermal method and subsequent annealing process. The structure, shape, and magnetic properties of the SNTs were investigated. Room-temperature and low-temperature magnetic measurements show that the as-fabricated γ-Fe2O3 SNTs are ferromagnetic, and its coercivity is nonzero when the temperature above blocking temperature (TB). The hysteresis loop was operated to show that the magnetic properties of γ-Fe2O3 SNTs are strongly influenced by the morphology of the crystal. The unique magnetic behaviors were interpreted by the competition of the demagnetization energy of quasi-one-dimensional nanostructures and the magnetocrystalline anisotropy energy of particles in SNTs.
Co-reporter:Wei Wu;Xiangheng Xiao;Shaofeng Zhang;Hang Li
Nanoscale Research Letters 2009 Volume 4( Issue 8) pp:
Publication Date(Web):2009 August
DOI:10.1007/s11671-009-9342-6
Water-soluble hollow spherical magnetite (Fe3O4) nanocages (ca. 100 nm) with high saturation magnetization are prepared in a one-pot reaction by sol-gel method and subsequent annealing to synthesise the maghemite (γ-Fe2O3) nanocages with similar nanostructures. The nanocages have been investigated by powder X-ray diffraction (XRD), transmission electron microscope (TEM), high-resolution transmission electron microscope (HRTEM), and superconducting quantum interference device (SQUID). The results indicated that glutamic acid played an important role in the formation of the cage-like nanostructures.
Co-reporter:L.X. Fan, D.L. Guo, F. Ren, Q. Fu, C.Z. Jiang
Solid State Communications 2008 Volume 148(7–8) pp:286-288
Publication Date(Web):November 2008
DOI:10.1016/j.ssc.2008.09.009
We present a novel approach to investigate the relationship between the ordered domains of nanopores in an anodic aluminum oxide (AAO) template and the underlying substrate grain boundary structure, by simultaneously analyzing the ordering of the concaves remnant on the surface of the aluminum and its grain boundary structure using Electron Backscatter Diffraction (EBSD). These observations show that the ordered domains of the AAO template can extend across the substrate grain boundaries and the mechanism is discussed.
Co-reporter:Wei Wu;Quanguo He
Nanoscale Research Letters 2008 Volume 3( Issue 11) pp:
Publication Date(Web):2008 November
DOI:10.1007/s11671-008-9174-9
Surface functionalized magnetic iron oxide nanoparticles (NPs) are a kind of novel functional materials, which have been widely used in the biotechnology and catalysis. This review focuses on the recent development and various strategies in preparation, structure, and magnetic properties of naked and surface functionalized iron oxide NPs and their corresponding application briefly. In order to implement the practical application, the particles must have combined properties of high magnetic saturation, stability, biocompatibility, and interactive functions at the surface. Moreover, the surface of iron oxide NPs could be modified by organic materials or inorganic materials, such as polymers, biomolecules, silica, metals, etc. The problems and major challenges, along with the directions for the synthesis and surface functionalization of iron oxide NPs, are considered. Finally, some future trends and prospective in these research areas are also discussed.
Co-reporter:X.H. Xiao, J.X. Xu, F. Ren, C. Liu, C.Z. Jiang
Physica E: Low-dimensional Systems and Nanostructures 2008 Volume 40(Issue 3) pp:705-708
Publication Date(Web):January 2008
DOI:10.1016/j.physe.2007.09.097
Ag nanoclusters are created in single-crystal MgO by ion implantation of 2×1017 Ag ions/cm2 at an energy of 200 keV and subsequent thermal annealing. The defect evolution is investigated by means of optical absorption spectroscopy. Optical absorption spectra show an absorption peak around 460 nm which belonged to the surface plasmon resonance absorption of Ag clusters in as-implanted and annealed samples in reducing atmosphere. With the increase in annealing temperature, the optical absorption peaks blueshift at lower temperature, then redshift for temperature higher than 600 °C and return to position after annealing at 900 °C. A new absorption peak belonging to Fn center is observed after annealing at 700 °C. Transmission electron microscopy (TEM) study indicates that the surface of MgO is amorphized and the ion-implanted layer is partly damaged; the damaged layer is recovered by annealing in reducing atmosphere at 900 °C.
Co-reporter:X.H. Xiao, F. Ren, J.B. Wang, C. Liu, C.Z. Jiang
Materials Letters 2007 Volume 61(Issue 22) pp:4435-4437
Publication Date(Web):September 2007
DOI:10.1016/j.matlet.2007.02.017
Synthesis of metal nanoparticles by ion implantation has a number of advantages. Nevertheless, certain remaining difficulties must be overcome in order to optimize the characteristics of ion-implanted nanocomposites. The principle among these are the lack of control over the size distribution and position of the precipitates within the implanted layer. Two-dimensionally ordered arrangements of Ag nanoparticles are formed in Ag-implanted silica glass by post-implanted Cu ions. The spherical Ag nanoparticles are formed to align at the same deep depth in the silica. Cross-sectional transmission electron microscopy revealed that the Ag nanoparticles are a size of 35–48 nm in diameter. The evolution of nanoparticles is characterized by transmission electron microscopy.
Co-reporter:Y.H. Wang, C.Z. Jiang, F. Ren, Q.Q. Wang, D.J. Chen, D.J. Fu
Physica E: Low-dimensional Systems and Nanostructures 2006 Volume 33(Issue 1) pp:244-248
Publication Date(Web):June 2006
DOI:10.1016/j.physe.2006.02.006
Metal nanocluster composites prepared by Cu ion implantation have been studied. The formation of nanoclusters has been evidenced by optical absorption spectra and transmission electron microscopy (TEM). Fast nonlinear optical refraction and nonlinear optical absorption coefficients were measured at 790 nm for Cu nanocluster composites by the Z-scan technique. With the increase of annealing temperature, the size of nanoclusters increased significantly, and optical nonlinearities was enhanced. It is suggested that by changing the ingredient configuration of metal nanoclusters in silica, different optical nonlinear properties could be selectively obtained.
Co-reporter:F. Ren, C.Z. Jiang, Y.H. Wang, Q.Q. Wang, J.B. Wang
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 2006 Volume 245(Issue 2) pp:427-430
Publication Date(Web):April 2006
DOI:10.1016/j.nimb.2005.11.052
Cu ions were implanted at 180 keV into silica at doses ranging from 5 × 1016 to 2 × 1017 ions/cm2 at a current density lower than 1.5 μA/cm2. Cross-sectional transmission electron microscopy and scanning transmission electron microscopy high-angle annular dark field images show that nanovoids have been formed in Cu nanoclusters in the implanted samples with doses higher than 1 × 1017 ions/cm2. These nanovoids growth up after the samples annealed in reducing atmosphere. The mechanism for the formation of nanovoids can be explained by the aggregation of vacancies into nanovoids during the process of ion implantation.
Co-reporter:F. Ren, C.Z. Jiang, L. Zhang, Y. Shi, J.B. Wang, R.H. Wang
Micron 2004 Volume 35(Issue 6) pp:489-493
Publication Date(Web):August 2004
DOI:10.1016/j.micron.2004.01.011
We report on the formation of alloy nanoclusters in silica by Ag/Cu ion sequential implantation. The formation of alloy nanocluster has been evidenced by optical absorption spectra, selected area electron diffraction and energy dispersive X-ray spectra. The microstructure characters of nanoclusters have been studied by high resolution transmission electron microscopy. The lattice distortion of some nanoclusters has been observed. A model has been given to explain the distortion. Some defects (partial dislocation, stacking faults) have been found in nanoclusters.
Co-reporter:Qingyong Tian, Wei Wu, Jun Liu, Zhaohui Wu, Weijing Yao, Jin Ding and Changzhong Jiang
Dalton Transactions 2017 - vol. 46(Issue 9) pp:NaN2777-2777
Publication Date(Web):2017/01/23
DOI:10.1039/C7DT00018A
The development of photocatalysts with superior photoactivity and stability for the degradation of organic dyes is very important for environmental remediation. In this study, we have presented a multidimensional (1D and 2D) structured CdS/ZnIn2S4/RGO photocatalyst with superior photocatalytic performance. The CdS/ZnIn2S4 helical dimensional heterostructures (DHS) were prepared via a facile solvothermal synthesis method to facilitate the epitaxial growth of 2D ZnIn2S4 nanosheets on 1D CdS nanowires. Ultrathin 2D ZnIn2S4 nanosheets have grown uniformly and perpendicular to the surface of 1D CdS nanowires. The as-obtained 1D/2D CdS/ZnIn2S4 helical DHS show good photocatalytic properties for malachite green (MG). Subsequently, 2D reduced graphene oxide (RGO) was introduced into the 1D/2D CdS/ZnIn2S4 helical DHS as a co-catalyst. The photoactivity and stability of the CdS/ZnIn2S4/RGO composites are significantly improved after 6 cycles. The enhanced photoactivity can be attributed to the high surface area of RGO, the improved adsorption of organic dyes and the efficient spatial separation of photo-induced charge carriers. The transfer of photo-generated electrons from the interface of CdS and ZnIn2S4 to RGO also restricted the photocorrosion of metal sulfide, suggesting an improved stability of the reused CdS/ZnIn2S4/RGO composited photocatalyst.
Co-reporter:Shaofeng Zhang, Feng Ren, Wei Wu, Juan Zhou, Xiangheng Xiao, Lingling Sun, Ying Liu and Changzhong Jiang
Physical Chemistry Chemical Physics 2013 - vol. 15(Issue 21) pp:NaN8236-8236
Publication Date(Web):2013/03/25
DOI:10.1039/C3CP50925G
Composite materials containing different components with well-defined structures may cooperatively enhance their performance and extend their applications. In this work, core–shell γ-Fe2O3@SnO2 hollow nanoparticles (NPs) were synthesized by a low-cost and environmentally friendly seed-mediated hydrothermal method. Firstly, the γ-Fe2O3 hollow NPs were synthesized by a template-free method. Then they were used as the cores for the growth of SnO2 shells. The thickness of the shell can be simply tailored by controlling the reaction time. Various techniques, including SEM, XRD, TEM and HRTEM, were employed to investigate the morphology, structure and formation process of the special core–shell hollow structures. The combination of magnetic semiconductor (γ-Fe2O3) and wide band-gap semiconductor (SnO2) endowed them with great potential to be used as recyclable photocatalysts. Experiments on photo-degradation of Rhodamin B (RhB) dye in the presence of the samples showed that the hybrid structures possessed higher photocatalytic activities than the monomer structures of SnO2 and γ-Fe2O3 materials indicating a strong coupling enhancement effect between the wide and narrow band-gap semiconductors. Moreover, the gas sensing tests of the γ-Fe2O3@SnO2 hollow NPs revealed that the samples exhibited fast response and recovery rates, which enable them to be promising materials for gas sensors.
Co-reporter:Juan Zhou, Feng Ren, Shaofeng Zhang, Wei Wu, Xiangheng Xiao, Ying Liu and Changzhong Jiang
Journal of Materials Chemistry A 2013 - vol. 1(Issue 42) pp:NaN13138-13138
Publication Date(Web):2013/08/29
DOI:10.1039/C3TA12540H
Tailorable synthesis of plasmon enhanced catalysts with high solar-light harvesting and energy-conversion efficiency has attracted wide interest due to its scientific and technological importance. In this paper, novel SiO2–Ag–SiO2–TiO2 multi-shell photocatalysts with wide-spectral-response were systematically designed and controllably synthesized, where the SiO2 spheres were used as the cores, and the SiO2 interlayers coated on the Ag nanoparticle (NP) shells were used to separate the Ag from the TiO2 shell. The structures of the SiO2–Ag–SiO2–TiO2 multi-shell photocatalysts can be tailored by changing the thickness of SiO2 interlayers from 1 to 2, 5, 8, 12, and 20 nm, while the anatase N-doped TiO2 shells with visible light response are maintained at a thickness of 20 nm. The photocatalytic activity tests show that the enhanced photocatalytic efficiency under both ultraviolet (UV) and visible light irradiation is related to the existence of Ag NP shells and the thickness of SiO2 interlayers. The complicated coupling mechanisms between TiO2 and a plasmon are systematically discussed, and a clear physical picture for the complicated coupling processes is presented. The main reasons for the enhancement of the photocatalytic activity of the SiO2–Ag–SiO2–TiO2 multi-shell structures are the localized surface plasmon resonance (LSPR) effect and scattering effect induced by Ag NPs.
Co-reporter:Jun Liu, Wei Wu, Qingyong Tian, Zhigao Dai, Zhaohui Wu, Xiangheng Xiao and Changzhong Jiang
Dalton Transactions 2016 - vol. 45(Issue 32) pp:NaN12755-12755
Publication Date(Web):2016/07/13
DOI:10.1039/C6DT02499H
Coupling two different semiconductors to form composite photocatalysts is the most significant method for environmental remediation. In this regard, tube-like α-Fe2O3/Ag6Si2O7 heterostructures are synthesized via anchoring p-type Ag6Si2O7 nanoparticles (NPs) on the surface of n-type α-Fe2O3 short nanotubes (SNTs) by conventional wet-chemical routes. α-Fe2O3 SNTs are firstly fabricated by a hydrothermal method with the assistance of dihydrogen phosphate and sulphate. Then, Ag6Si2O7 NPs are anchored on α-Fe2O3 SNTs by an in situ deposition method, and the α-Fe2O3/Ag6Si2O7 p–n heterostructures are finally obtained. The morphologies, crystal structure, photocatalytic performance and photocurrent properties of as-synthesized α-Fe2O3/Ag6Si2O7 heterostructures are investigated. Six organic dyes are used for determining the high-efficiency Z-scheme photocatalytic activities of the as-obtained photocatalysts under ultraviolet and visible light (mercury lamp, 300 W). Compared with pure α-Fe2O3 SNTs, the photocurrent intensity of the α-Fe2O3/Ag6Si2O7 heterostructures is improved 62 times. The enhanced significant photocatalytic performance of α-Fe2O3/Ag6Si2O7 heterostructures could be attributed to charge transfer between Ag6Si2O7 NPs and the charge separation between Ag6Si2O7 NPs and α-Fe2O3 SNTs. These composite heterostructures are proposed to be an example for the preparation of other composite silicate photocatalysts for practical application in environmental remediation issues.
