Interfacial engineering by creating Cu-based ternary heterostructures on C3N4 tubes towards enhanced photocatalytic oxidative coupling of benzylamines

Abstract

Benzylamine coupling is a very important reaction for the synthesis of imine but still faces many challenges. Herein, we present a highly effective strategy towards the coupling reaction by using environmentally friendly catalysts. These catalysts are composed of Cu/Cu₂O/Cu₃N heterostructures supported by C₃N₄ tubes and the composites were synthesized by one-step hydrothermal treatment followed by calcination. Cu₂O, Cu₃N, and C₃N₄ all are responsive to visible light and the heterojunction formed can greatly enhance the charge separation. When used as photocatalysts for oxidative self-coupling of benzylamine at a low temperature of 323 K in air, Cu/Cu₂O/Cu₃N/C₃N₄ was able to give conversion and selectivity values of up to 99% and 98%, respectively. The high efficiency of the catalysts is attributable to their ability to generate large quantities of free radicals (such as ·OH and ·O₂⁻) under visible-light irradiation.