標題: Metal-Particle-Decorated ZnO Nanocrystals: Photocatalysis and Charge Dynamics
作者: Lin, Wei-Hao
Chiu, Yi-Hsuan
Shao, Pao-Wen
Hsu, Yung-Jung
材料科學與工程學系
Department of Materials Science and Engineering
關鍵字: semiconductor/metal heterostructures;ZnO;photocatalysis;charge carrier dynamics;time-resolved photoluminescence
公開日期: 7-Dec-2016
摘要: Understanding of charge transfer processes is determinant to the performance optimization for semiconductor photocatalysts. As a representative model of composite photocatalysts, metal-particle-decorated ZnO has been widely employed for a great deal of photocatalytic applications; however, the dependence of charge carrier dynamics on the metal content and metal composition and their correlation with the photocatalytic properties have seldom been reported. Here, the interfacial charge dynamics for metal-decorated ZnO nanocrystals were investigated and their correspondence with the photocatalytic properties was evaluated. The samples were prepared with a delicate antisolvent approach, in which ZnO nanocrystals were grown along with metal particle decoration in a deep eutectic solvent. By modulating the experimental conditions, the metal content (from 0.6 to 2.3 at%) and metal composition (including Ag, Au, and Pd) in the resulting metal-decorated ZnO could be readily controlled. Time-resolved photoluminescence spectra showed that an optimal Au content of 1.3 at% could effectuate the largest electron transfer rate constant for Au-decorated ZnO nanocrystals, in conformity with the highest photocatalytic efficiency observed. The relevance of charge carrier dynamics to the metal composition was also inspected and realized in terms of the energy level difference between ZnO and metal. Among the three metal-decorated ZnO samples tested, ZnO-Pd displayed the highest photocatalytic activity, fundamentally according with the largest electron transfer rate constant deduced in carrier dynamics measurements. The current work was the first study to present the correlations among charge carrier dynamics, metal content, metal composition, and the resultant photocatalytic properties for semiconductor/metal heterostructures. The findings not only helped to resolve the standing issues regarding the mechanistic foundation of photocatalysis but also shed light on the intelligent design of semiconductor/metal composite systems to consolidate their utility in photocatalytic fields.
URI: http://dx.doi.org/10.1021/acsami.6b08132
http://hdl.handle.net/11536/132744
ISSN: 1944-8244
DOI: 10.1021/acsami.6b08132
期刊: ACS APPLIED MATERIALS & INTERFACES
Volume: 8
Issue: 48
起始頁: 32754
結束頁: 32763
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