摘要
本文设计了一种Cu纳米颗粒(NPs)修饰TiO2空心球壳的新型光催化剂(Cu/TiO2),这种金属/半导体光催化剂在紫外光和可见光下均能实现高效光催化全分解水.在报道过的TiO2基光催化剂中,Cu/TiO2的可见光全分解水活性处于最高水平.有趣的是,Cu和TiO2形成的金属/半导体结可以通过调节入射光波长(紫外光或可见光)来控制改变光催化分解水反应路径,进而实现对水氧化产物(H2O2或O2)的选择.在紫外光照射下,TiO2上的光生电子在Cu/TiO2肖特基结的作用下被Cu NPs捕获,并参与水还原反应产生H2,留在TiO2上的光生空穴通过两电子过程参与水氧化反应产生H2O2;在可见光下,Cu NPs的局域表面等离子共振(LSPR)效应发挥作用,产生热电子并将其注入至TiO2中,参与水还原反应产生H2,Cu NPs产生的热空穴通过四电子过程参与水氧化反应产生O2.这种功能可切换的金属/半导体结的设计可以对研究和理解光催化全分解水反应机理提供帮助.
A novel metal/semiconductor photocatalyst,Cu nanoparticles(NPs)modified TiO2 hollow spheres(Cu/TiO2),was designed for efficient photocatalytic overall water splitting(POWS)under both ultraviolet(UV)and visible(Vis)light.This Cu/TiO2 photocatalyst possesses excellent POWS performance under Vis light at the highest level among the reported TiO2-based photocatalysts.Interestingly,the metal/semiconductor junction formed between Cu and TiO2 enables controlled water-oxidation product selectivity(H2O2 or O2)via different reaction pathways regulated by irradiation wavelengths.Under UV light,the electrons excited in TiO2 are captured by Cu NPs through the Cu/TiO2 Schottky interface for H2 production,with the photoholes in TiO2 producing H2O2 through a two-electron process;whilst under Vis light,Cu NPs act as plasmon to inject hot electrons to TiO2 for H2 production,while O2 is produced by hot holes on Cu NPs via a four-electron process.This rational design of function-switchable metal/semiconductor junction may be helpful to understand the mechanisms for POWS with desired gas/liquid water-oxidation products.
作者
魏代星
谭余波
王亦清
孔婷婷
沈少华
Samuel S.Mao
Daixing Wei;Yubo Tan;Yiqing Wang;Tingting Kong;Shaohua Shen;Samuel S.Maoc(International Research Center for Renewable Energy,State Key Laboratory of Multiphase Flow in Power Engineering,Xi'an Jiaotong University,Xi'an 710049,China;College of Chemistry and Chemical Engineering,Xi'an Shiyou University,Xi'an 710054,China;Department of Mechanical Engineering,University of California at Berkeley,Berkeley,CA 94720,USA)
基金
the National Natural Science Foundation of China(51672210 and 21875183)
the National Key Research and Development Program of China(2017YFE0193900)
National Program for Support of Top-notch Young Professionals
Fundamental Research Funds for the Central Universities,Natural Science Basic Research Plan in Shaanxi Province of China(2018JQ2028)
China Postdoctoral Science Foundation(2018M640981)。
