標題: Heterojunction of Zinc Blende/Wurtzite in Zn1-xCdxS Solid Solution for Efficient Solar Hydrogen Generation: X-ray Absorption/Diffraction Approaches
作者: Hsu, Ying-Ya
Suen, Nian-Tzu
Chang, Chung-Chieh
Hung, Sung-Fu
Chen, Chi-Liang
Chan, Ting-Shan
Dong, Chung-Li
Chan, Chih-Chieh
Chen, San-Yuan
Chen, Hao Ming
材料科學與工程學系
加速器光源科技與應用學位學程
Department of Materials Science and Engineering
Master and Ph.D. Program for Science and Technology of Accelrrator Light Source
關鍵字: hydrogen evolution reaction (HER);zinc-cadmium sulfide;heterojunction;X-ray absorption;density of states (DOS) and Rietveld structural refinements
公開日期: 14-Oct-2015
摘要: In the past decade, inorganic semiconductors have been successfully demonstrated as light absorbers in efficient solar water splitting to generate chemical fuels. Pseudobinary semiconductors Zn1-xCdxS (0 <= x <= 1) have exhibited a superior photocatalytic reactivity of H-2 production from splitting of water by artificial solar irradiation without any metal catalysts. However, most studies had revealed that the extremely high efficiency with an optimal content of Zn1-xCdxS solid solution was determined as a result of elevating the conduction band minimum (CBM) and the width of bandgap. In addition to corresponding band structure and bandgap, the local crystal structure should be taken into account as well to determine its photocatalytic performance. Herein, we demonstrated the correlations between the photocatalytic activity and structural properties that were first studied through synchrotron X-ray diffraction and X-ray absorption spectroscopy. The crystal structure transformed from zinc blende to coexisted phases of major zinc blende and minor wurtzite phases at a critical point. The heterojunction formed by coexistence of zinc blende and wurtzite phases in the Zn1-xCdxS solid solution can significantly improve the separation and migration of photoinduced electron hole pairs. Besides, X-ray absorption spectra and UV-vis spectra revealed that the bandgap of the Zn0.45Cd0.55S sample extended into the region of visible light because of the incorporation of Cd element in the sample. These results provided a significant progress toward the realization of the photoelectrochemical mechanism in heterojunction between zinc blende and wurtzite phases, which can effectively separate the charge-carriers and further suppress their recombination to enhance the photocatalytic reactivity.
URI: http://dx.doi.org/10.1021/acsami.5b06872
http://hdl.handle.net/11536/128413
ISSN: 1944-8244
DOI: 10.1021/acsami.5b06872
期刊: ACS APPLIED MATERIALS & INTERFACES
Issue: 40
起始頁: 22558
結束頁: 22569
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