Effect of oxygen vacancies on the photocatalytic CO2 reduction performance of Bi2WO6: DFT and experimental studies

In order to improve the photocatalytic activity of Bi2WO6 (BWO) under solar light irradiation, introduction oxygen vacancies has attracted wide attention owing its simple synthesis method. However, intrinsic link between and CO2 reduction performance is still elusive. this work, density functional theory (DFT) calculations combining with experimental measurements verify that are inclined generate in [Bi2O2]2+ layers on BWO (0 1 0) surface, which results narrowed band gap improved electron-hole pair separation efficiency arising from formation Bi 6p impurity level. To best our knowledge, product CO obtained via reaction •H, intermediate species include •COOH, •CO, •OH, H2O. Owing surface chemical state variations, such as charge accumulation depletion upon vacancies, change remarkably adsorption configuration, so do energy barriers or without vacancies. Apparently, rate-limiting step for overall transition •COOH •CO corresponding activation barrier value reduced 2.83 eV 1.91 eV, because C–O bond breaks more easily after This work provides a new enlightenment insight into role process reducing CO2, paves ways design defective systems higher activity.