Integrating Z-scheme heterojunction of Co-CN@α-FeO for efficient visible-light-driven photocatalytic CO reduction

• Published in: Green chemistry : an international journal and green chemistry resource : GC 2020-11, Vol.22 (21), p.7552-7559
• Main Authors: He, Bing-Cai, Zhang, Chao, Luo, Pei-Pei, Li, Yu, Lu, Tong-Bu
• Format: Article
• Language: English
• ISSN: 1463-9262; 1463-9270
• DOI: 10.1039/d0gc02836c

Photocatalytic CO 2 reduction coupled with water oxidation provides a fascinating approach to mitigating the issues of global warming and energy shortage. Herein, a direct Z-scheme heterojunction of Co 1 -C 3 N 4 @α-Fe 2 O 3 comprising a g-C 3 N 4 -supported single-atomic Co site catalyst (denoted as Co 1 -C 3 N 4 ) and α-Fe 2 O 3 nanorod arrays is fabricated for efficient CO 2 reduction. A CO production rate of 14.9 μmol g −1 h −1 with a high CO selectivity (>99%) is achieved under visible-light irradiation without any sacrificial agents other than water. Time-resolved photoluminescence (TRPL) analysis reveals that both the Z-scheme mechanism and the single-atomic Co sites contribute to the prolonged lifetime of the photo-induced excitons. Moreover, the formation of the Z-scheme heterojunction would lead to an altered charge density of the single-atomic Co sites. In situ diffuse reflectance infrared Fourier-transform spectroscopy and anion adsorption measurements reveal that the key intermediate CO 2 − could be efficiently stabilized by the positively charged Co sites in Co 1 -C 3 N 4 @α-Fe 2 O 3 , thus enhancing the CO 2 reduction performance. This work offers a new direction for the rational design of single-atomic site catalysts in artificial photosynthesis. A direct Z-scheme heterojunction of Co 1 -C 3 N 4 @α-Fe 2 O 3 was constructed for efficient photocatalytic CO 2 reduction coupled with water oxidation under visible-light irradiation, with a CO generation rate of 14.9 μmol g −1 h −1 and CO selectivity over 99%.