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:Lan Dong, Hongxiu Zhang, Hiroshi Amekura, Feng Ren, Abdelhak Chettah, Mengqing Hong, Wenjing Qin, Jun Tang, Lulu Hu, Hui Wang, Changzhong Jiang
Journal of Nuclear Materials 2017 Volume 497(Volume 497) pp:
Publication Date(Web):15 December 2017
DOI:10.1016/j.jnucmat.2017.07.064
Nanostructured multilayers have been well proved to be highly tolerant to radiation comparing to traditional single-phase bulk materials, because the interfaces act as sinks to annihilate radiation-induced defects. The study on the response of same multilayered nanofilm to irradiation under different ion energies has not been reported. In this work, the immiscible Cu/W multilayered nanofilms with period-thicknesses of 6, 12, 18, and 24 nm were irradiated by ions at different energies (40 keV He+, 6.4 MeV Xe23+ and 200 MeV Xe14+). For the irradiation of 40 keV He+ ions, He bubbles density decreases with decreasing period-thickness. In the case of the irradiation by 6.4 MeV Xe23+ ions, the interface-mixing only appears in the multilayered nanofilm with the largest period-thickness. Under the irradiation with 200 MeV Xe14+ ions, structure damage only occurs in the bottom layers of the multilayered nanofilm with period-thickness of 12 nm. All these experiments show that the Cu/W multilayered nanofilm with the smallest period-thickness possesses the best radiation resistance to ions irradiation with different energies.
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:Xudong Zheng, Shaohua Shen, Feng Ren, Guangxu Cai, Zhuo Xing, Yichao Liu, Dan liu, Guozhen Zhang, Xiangheng Xiao, Wei Wu, Changzhong Jiang
International Journal of Hydrogen Energy 2015 Volume 40(Issue 15) pp:5034-5041
Publication Date(Web):27 April 2015
DOI:10.1016/j.ijhydene.2015.02.087
•Well-order TiO2 nanorods with controlled size were fabricated by ion irradiation.•N+ irradiation causes the formation of oxygen vacancies and the doping of nitrogen.•Irradiation enhances the performance of photoelectrochemical water splitting.•7 times higher photocurrent density is achieved.In this work, well-ordered nanorods were fabricated on the surface of TiO2 thin films deposited on Ti sheets by an ion irradiation method using nitrogen ion irradiation with the energy of 65 keV to a fluence of 1 × 1017 ions/cm2. These TiO2 nanorods are about 120 nm in length and 20–40 nm in diameter. After post-irradiation annealing at 500 °C in O2, the nanorod array photoelectrode displays largely enhanced performance for photoelectrochemical (PEC) water splitting compared to that of the un-irradiated TiO2 thin films with a planar structure. The influences of the irradiated ion energy on the morphology and photocurrent density of the nanorods were investigated. The 65 keV N+ irradiated TiO2 thin films shows a higher photocurrent density than those of the 45 and 85 keV N+ irradiated TiO2 thin films. We also discussed the influence of annealing conditions on the PEC performance of TiO2 nanorods, and it was found that the nanorods annealed at 600 °C in vacuum produce a much higher photocurrent density of 0.6 mA/cm2 at 0.8 V (vs. a saturated calomel electrode), which is about 7 times higher than that of the nanorods annealed in oxygen. This work proposes that ion irradiation combination with thermal annealing in vacuum could be an effective approach for developing nanostructured materials for water splitting.
Co-reporter:Hongxiu Zhang, Feng Ren, Yongqiang Wang, Mengqing Hong, Xiangheng Xiao, Wenjing Qin, Changzhong Jiang
Journal of Nuclear Materials 2015 Volume 467(Part 2) pp:537-543
Publication Date(Web):December 2015
DOI:10.1016/j.jnucmat.2015.10.017
•An in situ study on the growth of He bubbles during annealing was performed by TEM.•Bubbles in Ag were confined by the neighboring V.•Bubbles in the Ag layers grew rapidly by the vacancy or helium absorption.•Bubbles in the V layers evolved slowly.Multilayers have been considered as promising candidates for nuclear materials. In this paper, an in situ study on the growth of helium bubbles during annealing was performed by transmission electron microscopy. Bubbles in the Ag layers grew rapidly by vacancy absorption mechanism and reached a size comparable to the layer thickness, whereas bubbles in the V layers evolved slowly due to the lower diffusion rate of vacancies and stopped growing at the size of 1.8 nm. The interfaces with more than one orientation relationship in the V/Ag multilayer contained pockets of excess volumes that can readily trap helium and exhibit high helium solubility. The interfaces prevent bubbles from growing into nearby layers.
Co-reporter:Mengqing Hong, Feng Ren, Yongqiang Wang, Hongxiu Zhang, Xiangheng Xiao, Dejun Fu, Bing Yang, Changzhong Jiang
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 2015 342() pp: 137-143
Publication Date(Web):1 January 2015
DOI:10.1016/j.nimb.2014.09.032
This paper demonstrates a substantial enhancement in radiation tolerance and corrosion resistance for the CrN/AlTiN multilayered nanofilms with the decreasing of period-thickness. After irradiation by 190 keV Ar+ ions to the dose of 81 dpa, the amorphization region in the CrN/AlTiN 3 nm multilayered nanofilm is much smaller than that in the CrN/AlTiN 7 nm multilayered nanofilm and the CrN film based on glancing-incidence X-ray diffraction measurements. Potentiodynamic polarization and impedance measurements show that the CrN/AlTiN multilayered nanofilms have good corrosion resistance to irradiation. With increasing the irradiation fluence, the irradiated samples are more susceptible to corrosive electrolyte. However, the CrN/AlTiN multilayered nanofilm with smaller period-thickness shows significant enhancement of the corrosion resistance under both irradiation and un-irradiation conditions. Under the same irradiation fluence of 5 × 1016 ions/cm2, the corrosion current density increased 9.47 times for the CrN film, while it only increased 2.08 times for the CrN/AlTiN 3 nm multilayered nanofilm. The interfaces of multilayered nanofilms act as effective sinks for irradiation-induced defects and are responsible for the enhanced radiation tolerance and corrosion resistance properties.
Co-reporter:Qingyong Tian, Wei Wu, Lingling Sun, Shuanglei Yang, Mei Lei, Juan Zhou, Ying Liu, Xiangheng Xiao, Feng Ren, Changzhong Jiang, and Vellaisamy A. L. Roy
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 15) pp:13088
Publication Date(Web):July 3, 2014
DOI:10.1021/am5029439
Heterogeneous photocatalysis is of great interest for environmental remediation applications. However, fast recombination of photogenerated electron–hole pair and a low utilization rate of sunlight hinder the commercialization of currently available semiconductor photocatalysts. In this regard, we developed a unique ternary single core-double shell heterostructure that consists of α-Fe2O3@SnO2@Cu2O. This heterostructure exhibits a tube-like morphology possessing broad spectral response for the sunlight due to the combination of narrow bandgap and wide bandgap semiconductors forming a p–n heterojunction. To fabricate such a short nanotube (SNT), we used an anion-assisted hydrothermal route for deposition of α-Fe2O3, a seed-mediated deposition strategy for SnO2, and finally an aging process to deposit a Cu2O layer to complete the tube-like ternary α-Fe2O3@SnO2@Cu2O single core-double shell heterostructures. The morphology, composition, and photocatalytic properties of those ternary core–shell–shell heterostructures were characterized by various analytical techniques. These ternary heterostructures exhibited enhanced photocatalytic properties on the photodegradation of the organic dye of Rhodamine B (RhB) under simulated sunlight irradiation. The origin of enhanced photocatalytic activity is due to the synergistic effect of broad spectral response by combining narrow bandgap and wide bandgap semiconductors and, hence, an efficient charge separation of photogenerated electron–hole pairs facilitated through the p–n heterojunction. Furthermore, our unique structure provides an insight on the fabrication and controlled preparation of multilayer heterostructural photocatalysts that have intriguing properties.Keywords: iron oxide; multilayer heterostructure; photocatalytic activity; p−n heterojunction
Co-reporter:Shaofeng Zhang, Feng Ren, Wei Wu, Juan Zhou, Lingling Sun, Xiangheng Xiao, Changzhong Jiang
Journal of Colloid and Interface Science 2014 Volume 427() pp:29-34
Publication Date(Web):1 August 2014
DOI:10.1016/j.jcis.2013.12.012
•Ag-α-Fe2O3 hybrids were synthesized by a novel self-catalytic growth method.•Size of Ag NPs could be well tailored by the reaction time.•Ag-α-Fe2O3 hybrids show superior photocatalytic activities.•Catalytic activity increases with the increase in the size of Ag NPs.•We report a size effect mechanism on the photocatalytic activities.Composite photocatalysts that consist of semiconductor and noble metal nanostructures have been considered to be the promising and crucial materials for straightforward improving the efficiency in photocatalytic process and for the conversion of solar to chemical energy. In this work, we fabricated Ag-α-Fe2O3 hybrid composites through a self-catalytic growth method by using the aldehyde-modified spindle α-Fe2O3 nanoparticles (NPs) as supports. The size of supported Ag NPs can be directly controlled on the surface of α-Fe2O3. The morphology and structure of the resulting Ag-α-Fe2O3 hybrid composites were studied by various techniques, including SEM, TEM, and XRD. The distinct photocatalytic behaviors were examined through the photodegradation of RhB dye. It was found that with the Ag NPs, the photocatalytic activities were enhanced greatly and the size of the Ag NPs played a crucial influence on the photocatalytic behaviors of the Ag-α-Fe2O3 composites.
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:Yichao Liu, Feng Ren, Guangxu Cai, Xiaodong Zhou, Mengqing Hong, Wenqing Li, Xiangheng Xiao, Wei Wu, Changzhong Jiang
Materials Research Bulletin 2014 51() pp: 376-380
Publication Date(Web):
DOI:10.1016/j.materresbull.2013.12.040
Co-reporter:Hongxiu Zhang, Feng Ren, Yongqiang Wang, Mengqing Hong, Xiangheng Xiao, Dan Liu, Wenjing Qin, Xudong Zheng, Yichao Liu, Changzhong Jiang
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 2014 Volume 334() pp:1-7
Publication Date(Web):1 September 2014
DOI:10.1016/j.nimb.2014.05.003
•Nanochannel V films were fabricated to achieve radiation tolerance.•Defects can diffuse to the free surfaces of V films through the channels.•The size and density of He bubbles are suppressed in the V nanochannel films.•Radiation hardening is suppressed in the V nanochannel films.Since surfaces are perfect sinks for defects, nanochannel material with a high surface to volume ratio has the potential to be extremely radiation tolerant. Nanochannel V films deposited at 500 °C and 600 °C, Ag and V/Ag multilayer films deposited at room temperature and bulk V, were subjected to He irradiation. TEM images show larger bubbles appeared in the Ag film and the V/Ag multilayer under He+ ion irradiation to a fluence of 5 × 1016 ions/cm2. While few small He bubbles formed in the irradiated nanochannel V film and a high density of small bubbles appeared in the irradiated bulk V when the fluence of He+ ions reaches 1 × 1017 ions/cm2, which is two times higher than the fluences on the Ag and multilayer films. Radiation-induced defects can quickly diffuse to the free surfaces of the nanochannels, which greatly reduces the concentration of defects in material and increases the radiation tolerance. Radiation hardening is observed in all specimens. The irradiation-induced hardening in the V nanochannel films is around one third to one fourth of that in the bulk V.
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: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: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:Shaofeng Zhang;Dr. Wei Wu; Xiangheng Xiao;Juan Zhou;Jinxia Xu; Feng Ren; Changzhong Jiang
Chemistry – An Asian Journal 2012 Volume 7( Issue 8) pp:1781-1788
Publication Date(Web):
DOI:10.1002/asia.201200348
Abstract
Supported noble bimetallic nanomaterials have attracted great interest owing to their applications in catalysis. Herein, polystyrene-supported Ag@AgAu bimetallic nanocomposites were synthesized by using a seed-growth route. The size and degree of coverage of the Ag@AgAu NPs could be controlled by changing the experimental parameters. SEM, TEM, STEM, EDS, and XPS analysis was used to characterize the morphology, structure, and composition of these nanocomposites. We found that the bimetallic nanoparticles on the polystyrene beads had a core–shell structure that was comprised of a Ag core and a AgAu alloy shell. The optical properties of the nanocomposites were also studied by UV/Vis/NIR spectroscopy, which indicated that the localized surface plasmon resonance (LSPR) absorptions of the nanocomposites could be tailored over a large scale from 450 nm to 950 nm. The catalytic properties of the nanocomposites were studied by using the reduction of 4-nitrophenol (4-NP) by NaBH4 as a model system. The results showed that the catalytic activity of the polystyrene-supported Ag@AgAu bimetallic nanocomposites was remarkably superior to that of polystyrene-supported monometallic Ag and Au nanocomposites with the same nanoparticle size. In addition, an investigation of the recycling catalytic activity of the PS-Ag@AgAu nanocomposites revealed that the catalyst possessed good stability. The enhancement of the catalytic activity was proposed to be due to the ligand and strain effects between Ag and Au.
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: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.
