Synthesis of small size lead-free Cs 3 Bi 2 x Sb 2−2 x Br 9 solid-solutions using a spatially confined growth method for efficient photocatalytic CO 2 reduction

• Published in: Catalysis science & technology Vol. 14; no. 3; pp. 758 - 766
• Main Authors: Gao, Miaomiao, Liu, Xiaolei, Yin, Liwen, Chen, Jinghang, Wang, Zeyan, Zheng, Zhaoke, Liu, Yuanyuan, Cheng, Hefeng, Dai, Ying, Huang, Baibiao, Zhang, Zehui, Wang, Peng
• Format: Journal Article
• Language: English
• Published: 05.02.2024
• ISSN: 2044-4753; 2044-4761
• DOI: 10.1039/D3CY01459B

The sustainable reduction of CO 2 to chemical fuels through photocatalysis is a promising research direction. However, most photocatalysts still face the issues of narrow light absorption, small specific surface area, and poor charge separability. Herein, Cs 3 Bi 2 x Sb 2−2 x Br 9 (CBSB- X ) solid solutions with good visible light absorption are successfully prepared. Moreover, small-sized CBSB- X nanoparticles can be obtained by spatially confined growth of CBSB- X in MCM-41 molecular sieve. The MCM-41@CBSB- X samples with a large specific surface area and efficient carrier transport demonstrate excellent photocatalytic CO 2 reduction to CO activity. In the gas–solid reaction system irradiated by visible light, the optimal MCM-41@Cs 3 Bi 0.6 Sb 1.4 Br 9 (MCM-41@CBSB-0.3) composite shows an excellent photocatalytic activity with a CO yield of 11.2 μmol g −1 h −1 , which is 5.9 and 15.1 times higher than that of bulk CBSB-0.3 and Cs 3 Bi 2 Br 9 (CBB), respectively. Temperature programmed desorption measurement proves that the MCM-41@CBSB-0.3 composite promotes CO 2 adsorption compared to bulk CBSB-0.3. The gradually generated COOH* intermediate detected by in situ infrared spectroscopy is the reason for the high selective CO production. This work provides a new idea for the synthesis of small-sized perovskites, which inspires the design and application of other lead-free perovskites in photocatalysis.