Oxygen Vacancy Engineering of Bi24O31Cl10 for Boosted Photocatalytic CO2 Conversion

• Published in: ChemSusChem 2019-06, Vol.12 (12), p.2740-2747
• Main Authors: Jin, Xiaoli, Lv, Chade, Zhou, Xin, Ye, Liqun, Xie, Haiquan, Liu, Yue, Su, Huan, Zhang, Biao, Chen, Gang
• Format: Article
• Language: English
• Subjects: Bi24O31Cl10; Carbon dioxide; Carbon monoxide; Carrier density; Charge transfer; CO generation; CO2 reduction; Conduction bands; Current carriers; Oxygen; oxygen vacancies; Photocatalysis; Photocatalysts; Photochemistry; Solar energy conversion; Vacancies
• ISSN: 1864-5631; 1864-564X
• DOI: 10.1002/cssc.201900621

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. Triple boost! The high abundance of oxygen vacancies in Bi24O31Cl10 play the following three roles for fully optimizing the CO2 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.