Solid-state synthesis of lead-free perovskite Cs3Bi2Br9 for photocatalytic O2-involved coupling of aldehydes or alcohols to anhydrides

Herein, a green and highly efficient strategy was developed to fabricate lead-free perovskite Cs₃Bi₂Br₉ through solid-state mechanochemical process under mild conditions, wherein the effects of rotation speed, grinding duration and ball-to-powder ratio on the formation of Cs₃Bi₂Br₉ powers were investigated. The photocatalytic performance of the as-prepared Cs₃Bi₂Br₉ powers was evaluated for catalyzing oxidative coupling of various aldehydes or alcohols to anhydrides using O₂ as the sole oxidant. Furthermore, a probable reaction mechanism was proposed basing on series active species capture experiments.