In situ solvothermal reduction engineering enables delicate control over surface-rich oxygen vacancies on Bi2WO6 for highly efficient photocatalytic CO2 reduction

Abstract

The high binding energy of CO bonds in CO₂ severely inhibits the photocatalytic CO₂ reduction (PCR) activity. Constructing oxygen vacancies (Vo) is considered as a fascinating strategy to promote the capture and activation of CO₂ molecules. The main challenge, however, lies in the delicate control of the Vo distribution, since the bulk Vo can act as a recombination centre for photogenerated electron–hole pairs. Here, an in situ solvothermal reduction strategy is presented by programming temperature to accurately control the Vo distribution on the catalytic surface. Taking Bi₂WO₆ as a model, surface-rich Vo on Bi₂WO₆ (Sur-Vo-BWO) were generated. The governable Vo distribution strategy remarkably increases the PCR dynamics with a high CO evolution rate for Sur-Vo-BWO (18.73 μmol g⁻¹ h⁻¹), which is 8.32 times more than that of the Vo-free control sample. This work paves a new pathway to implement delicate control of the Vo distribution on the catalysts for precisely tuned catalytic activity.