Sulfur-vacancy induced asymmetric active site for Bi19S27Br3 nanorods photocatalyzes CO2 conversion to ethylene

• Published in: Applied catalysis. B, Environmental Environmental, 2025-02, Vol.361, p.124647, Article 124647
• Main Authors: Zhao, Junze, Chen, Hailong, Wang, Bin, Ji, Mengxia, Su, Dong, Song, Li, Zhang, Pengjun, She, Yuanbin, Weng, Yu-Xiang, Li, Huaming, Xia, Jiexiang
• Format: Article
• Language: English
• Subjects: Bi19S27Br3; C2H4 products; Charge-polarized active sites; Photocatalyst; S-vacancy
• ISSN: 0926-3373
• DOI: 10.1016/j.apcatb.2024.124647

The photocatalytic conversion of CO2 into high value-added C2 products remains a significant challenge due to the limited active sites and high energy barrier of C-C coupling process. Herein, the sulfur-vacancy was established on the surface of Bi19S27Br3 nanorods, leading to the electron on residual S atoms become unstable and active. Under the light irradiation, the photoexcited electron transfer from S atoms to neighboring Bi atoms to generate in-situ charge-polarized Bi(3-x)+ asymmetric active sites, which can enhance CO2 adsorption-activation capacity and regulate C-C coupling process for the C1 intermediate. The experimental results and theoretical calculation confirm that more charges aggregate around the induced Bi atoms, reducing the energy barrier of the C-C coupling reaction and improving C2H4 formation. Consequently, the sulfur-vacancy Bi19S27Br3 nanorods achieve efficient C2H4 generation through photocatalytic CO2 reduction, which C2H4 formation rate is 17.80 µmol g−1 after 5-hour photocatalytic reaction, with the product selectivity and electron selectivity of 49 % and 85 %, respectively, outperforming the low sulfur-vacancy Bi19S27Br3 nanorods by four-folds. This research provides new insights into the design of photocatalysts. [Display omitted] •The novel Bi19S27Br3 nanorods with sulfur-vacancy have been synthesized.•The sulfur-vacancy induces the generation of surface charge-polarized Bi(3-x)+ asymmetric active sites.•The Bi19S27Br3 nanorods with sulfur-vacancy exhibit the enhanced C2H4 yield during photocatalytic CO2 reduction process.