Prolonged lifetime and enhanced separation of photo- generated charges of nanosized α-Fe2O3 by coupling SnO2 for efficient visible-light photocatalysis to convert C02 and degrade acetaldehyde  

作　　者：Zhijun Li Peng Luan Xuliang Zhang Yang Qu Fazal Raziq Jinshuang Wang Liqiang Jing 

机构地区：[1]Key Laboratory of Functional Inorganic Materials Chemistry (Heilongjiang University), Ministry of Education, School of Chemistry and Materials Science, International Joint Research Center for Catalytic Technology, Heilongjiang University, Harbin 150080, China

出　　处：《Nano Research》2017年第7期2321-2331,共11页纳米研究（英文版）

基　　金：We are grateful for financial support from the National Natural Science Foundation of China （Nos. U1401245 and 21501052）, the National Basic Research Program of China （No. 2014CB660814）, the Project of Chinese Ministry of Education （No. 213011A）, Special Funding for Postdoctoral of Heilongjiang Province （No. LBH- TZ06019） and the Science Foundation for Excellent Youth of Harbin City of China （No. 2014RFYXJ002）.

摘　　要：To develop efficient visible-light photocatalysis on α-Fe2O3, it is highly desirable to promote visible-light-excited high-energy-level electron transfer to a proper energy platform thermodynamically. Herein, based on the transient-state surface photovoltage responses and the atmosphere-controlled steady-state surface photovoltage spectra, it is demonstrated that the lifetime and separation of photogenerated charges of nanosized α-Fe2O3 are increased after coupling a proper amount of nanocrystalline SnO2. This naturally leads to greatly improved photocatalytic activities for CO2 reduction and acetaldehyde degradation. It is suggested that the enhanced charge separation results from the electron transfer from α-Fe2O3 to SnO2, which acts as a proper energy platform. Based on the photocurrent action spectra, it is confirmed that the coupled SnO2 exhibits longer visible-light threshold wavelength （-590 nm） compared with the coupled TiO2 （-550 nm）, indicating that the energy platform introduced by SnO2 would accept more photogenerated electrons from α-Fe2O3. Moreover, electrochemical reduction experiments proved that the coupled SnO2 possesses better catalytic ability for reducing CO2 and O2. These are well responsible for the much efficient photocatalysis on SnO2-coupled α-Fe2O3.To develop efficient visible-light photocatalysis on α-Fe2O3, it is highly desirable to promote visible-light-excited high-energy-level electron transfer to a proper energy platform thermodynamically. Herein, based on the transient-state surface photovoltage responses and the atmosphere-controlled steady-state surface photovoltage spectra, it is demonstrated that the lifetime and separation of photogenerated charges of nanosized α-Fe2O3 are increased after coupling a proper amount of nanocrystalline SnO2. This naturally leads to greatly improved photocatalytic activities for CO2 reduction and acetaldehyde degradation. It is suggested that the enhanced charge separation results from the electron transfer from α-Fe2O3 to SnO2, which acts as a proper energy platform. Based on the photocurrent action spectra, it is confirmed that the coupled SnO2 exhibits longer visible-light threshold wavelength （-590 nm） compared with the coupled TiO2 （-550 nm）, indicating that the energy platform introduced by SnO2 would accept more photogenerated electrons from α-Fe2O3. Moreover, electrochemical reduction experiments proved that the coupled SnO2 possesses better catalytic ability for reducing CO2 and O2. These are well responsible for the much efficient photocatalysis on SnO2-coupled α-Fe2O3.

关 键 词：SnO2-Fe2O3 nanocomposite electron transfer visible-light photocatalysis CO2 conversion acetaldehyde degradation 

分 类 号：O643.36[理学—物理化学] TB381[理学—化学]