A stable and recyclable Z-scheme g-C3N4/rGO/BiVO4 heterojunction photocatalyst for site-selective C-3 formylation of indoles with methanol as a formyl source under visible light

Abstract

A stable and recyclable Z-scheme g-C₃N₄/rGO/BiVO₄ heterojunction photocatalyst was constructed by a facile two-step hydrothermal procedure. The photocatalyst was used for the synthesis of C-3 formylated indoles from indoles with methanol as an atom-economical formyl source for the first time, and 30% g-C₃N₄/rGO/BiVO₄ exhibited superior photocatalytic efficiency. Quenching experiments showed that the photogenerated electrons and holes were the main photoactive species to achieve the reaction. This formylation reaction has the advantages of exceptional functional group tolerance, reusable photocatalysts, and mild reaction conditions. Gram scale synthesis indicated the future prospects of this strategy for real applications.