Oxygen Vacancy Engineering of Bi24O31Cl10 for Boosted Photocatalytic CO2 Conversion

Graphical Triple boost ! The high abundance of oxygen vacancies in Bi 24 O 31 Cl 10 play the following three roles for fully optimizing the CO 2 conversion efficiency: (i) enhance charge density, (ii) improve separation of electron–hole pairs, and (iii) lower energy for the formation of intermediates during the process. Unearthing an ideal model to describe the role of defect sites for boosting photocatalytic CO 2 reduction is rational and necessary, but it still remains a significant challenge. Herein, oxygen vacancies are introduced on the surface of Bi 24 O 31 Cl 10 photocatalyst (Bi 24 O 31 Cl 10 -OV) for fine-tuning the photocatalytic efficiency. The formation of oxygen vacancies leads to a new donor level near the conduction band minimum, which enables a faster charge transfer and higher carrier density. Moreover, oxygen vacancies can considerably reduce the energy for the formation of COOH* intermediates during CO 2 conversion. As a result, the activity of Bi 24 O 31 Cl 10 -OV for selective photoreduction of CO 2 to CO is significantly improved, with a CO generation rate of 0.9 μmol h −1 g −1 , which is nearly 4 times higher than that of pristine Bi 24 O 31 Cl 10 . This study reinforces our understanding of defect engineering in Bi-based photocatalysts and underscores the potential importance of implanting oxygen vacancies as an effective strategy for solar energy conversion.