Understanding dual-vacancy heterojunction for boosting photocatalytic CO2 reduction with highly selective conversion to CH4

The selective reduction of carbon dioxide (CO2) as the primary component of greenhouse gas, remains a significant challenge in photocatalysis. Here, we present a novel strategy of preparing highly selective and stable heterostructure photocatalysts, which simultaneously contain oxygen and nitrogen vacancies. Synergistic catalysis effect originated from Nb2O5 with oxygen vacancies and nitrogen-rich vacancies of metal-free catalytic (g-C3N4) substrate leads to excellent photocatalytic reduction performances. The as-prepared photocatalysts exhibit outstanding capacity of selective reduction of CO2 with yields of CH4 16.07 mu mol g(-1) and CO 0.89 mu mol g(-1) after 5 cycles. Furthermore, the CO2 reduction mechanism is confirmed through density functional theory (DFT) calculation and in-situ technology in detailing. This indicates that the heterojunction surface has a lower free energy barrier for CO2 reduction compared with the pristine sample surface. This new strategy may exploit a vital application of dual-vacancy heterostructure in environmental catalysis.

Automated summary

A novel strategy for preparing highly selective and stable heterostructure photocatalysts with oxygen and nitrogen vacancies has been proposed, showing excellent photocatalytic reduction performances. The CO2 reduction mechanism has been confirmed and the results indicate potential applications in environmental catalysis.