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

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/CuO/CuN heterostructures supported by CN tubes and the composites were synthesized by one-step hydrothermal treatment followed by calcination. CuO, CuN, and CN 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/CuO/CuN/CN 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 ·O ) under visible-light irradiation.