Engineering Efficient p-n Heterojunction of g-C₃N₄/Cu₂O for Visible Light-Mediated Suzuki-Miyaura Cross-Coupling...

The engineering of effective photocatalysts is essential for efficient solar-to-chemical energy conversion in photocatalytic CC coupling reactions. Herein, we report an effective approach for designing Pd nanoparticles (NPs) on g-C₃N₄/Cu₂O heterojunction, resulting in hybrids with extraordinary photocatalytic activity in Suzuki-Miyaura cross-coupling reactions under visible light. The combination of g-C₃N₄ and Cu₂O is akin to a p-n junction, which facilitates charge transport, suppresses the exciton recombination, and improves the overall visible light absorption efficiency. Upon illumination, the excited electrons from the p-n junction get transferred to the Pd NPs, making it electron-rich, which accelerates the rate-determining step, thereby the oxidative addition of aryl halides. Pd/g-C₃N₄/Cu₂O heterojunction showed one of the highest turnover frequencies (2502 h^-1) for photocatalytic CC coupling reactions among previously reported photocatalysts and is significantly better than the Pd/g-C₃N₄ and Pd/Cu₂O NCs composites under identical conditions. The heterojunction also showed a negligible loss in activity after the fifth catalytic cycle. Our approach provides an efficient photocatalytic route for the preparation of biaryl compounds that can potentially be extended to various other organic phototransformation reactions.