Space-restricted proliferation of Bi-based halide perovskite nanocrystals for visible-light-driven selective oxidation of benzyl alcohol

Photocatalytic synthesis of carbonyl compounds (aldehydes or ketones) offers great potential for sustained development in the production of pharmaceuticals and fine chemicals. Nevertheless, exploring photocatalysts with high stability, activity, and selectivity remains a significant challenge. In this study, Cs 3 Bi 2 Br 9 (CBB) perovskite nanocrystals have been successfully fabricated by confining the in-situ growth of perovskite CBB within mesoporous molecular sieve SBA-3. The obtained nanocrystals (2–4 nm) possess the advantages of excellent stability, exceptional dispersibility, abundant active sites, and enhanced charge carrier separation capability. Under visible light irradiation and air atmosphere, the CBB@SBA-3 could effectively oxidize benzyl alcohol to benzaldehyde with a total yield of 98.9 μmol, which is 22 times superior to that of bulk CBB, accompanied by a remarkable 99 % selectivity. Comparative experiments and in situ characterizations reveal the roles of electron ( e − ), hole ( h + ), and superoxide radical (·O 2 − ), while successfully capturing the carbon intermediates (·C) during the reaction process, further providing a comprehensive elucidation of the mechanism underlying the conversion of benzyl alcohol to benzaldehyde. This work is expected to provide insights into extending the design and photocatalytic application of Bi-based halide perovskite nanocrystals.