材料科学
光催化
氧化物
异质结
催化作用
二氧化碳电化学还原
漫反射红外傅里叶变换
半导体
光化学
氢
化学工程
甲烷
化学
光电子学
一氧化碳
有机化学
冶金
工程类
作者
Risov Das,Shreya Sarkar,Ritesh Kumar,S.D. Ramarao,Arjun Cherevotan,Mohammed Jasil,C. P. Vinod,Abhishek K. Singh,Sebastian C. Peter
标识
DOI:10.1021/acscatal.1c04587
摘要
Sunlight-driven CO2 hydrogenation has drawn tremendous attention. However, selective CH4 formation via CO2 photoreduction is very challenging. Herein, we report a metal oxide semiconductor heterojunction consisting of BiVO4 and WO3 as a photocatalyst for the efficient conversion of carbon dioxide (CO2) selectively to methane (105 μmol g–1 h–1) under visible light in the absence of a sacrificial agent. Wise selection of the reaction medium and the strategically tuned heterojunction upon strain relaxation suppresses the competitive hydrogen generation reaction. The detailed photophysical, photoelectrochemical, and X-ray absorption spectroscopy studies pointed to the Z-scheme mechanism of electron transfer, which favors superior electron and hole separation compared to the individual components of the composite catalyst and other well-known photocatalysts reported for CO2 reduction. The observations are further corroborated by experimental diffuse reflectance infrared Fourier transform spectroscopy and theoretical density-functional theory calculations, which reveal that the heterojunction has a lower free-energy barrier for CO2 conversion to CH4 due to the larger stabilization of the *CH2O intermediate on the strain-relaxed heterojunction surface, in comparison to the pristine BiVO4 surface. The present work provides fundamental insights for constructing high-performance heterojunction photocatalysts for the selective conversion of CO2 to desired chemicals and fuels.
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