Lead-Free Cs3Bi2Br9 Perovskite as Photocatalyst for Ring-Opening Reactions of Epoxides

Herein, an innovative approach was developed by using stable, lead-free halide perovskite for solar-driven organic synthesis. The ring-opening reaction of epoxides was chosen as a model system for the synthesis of value-added beta-alkoxy alcohols, which require energy-intensive process conditions and corrosive, strong acids for conventional synthesis. The developed concept included the in situ preparation of Cs3Bi2Br9 and its simultaneous application as photocatalyst for epoxide alcoholysis under visible-light irradiation in air at 293 K, with exceptional high activity and selectivity >= 86 % for beta-alkoxy alcohols and thia-compounds. The Cs3Bi2Br9 photocatalyst exhibited good stability and recyclability. In contrast, the lead-based perovskite showed a conversion rate of only 1 %. The origin of the unexpected catalytic behavior was attributed to the combination of the photocatalytic process and the presence of suitable Lewis-acidic centers on the surface of the bismuth halide perovskite photocatalyst.