Oxygen Vacancy Engineering of Bi₂₄O₃₁Cl₁₀ for Boosted Photocatalytic CO₂ Conversion

Unearthing an ideal model to describe the role of defect sites for boosting photocatalytic CO₂ reduction is rational and necessary, but it still remains a significant challenge. Herein, oxygen vacancies are introduced on the surface of Bi₂₄O₃₁Cl₁₀ photocatalyst (Bi₂₄O₃₁Cl₁₀-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 CO₂ conversion. As a result, the activity of Bi₂₄O₃₁Cl₁₀-OV for selective photoreduction of CO₂ 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 Bi₂₄O₃₁Cl₁₀. 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.