Harnessing photocatalytic activity of mesoporous graphitic carbon nitride decorated by copper single-atom catalysts for oxidative dehydrogenation of N-heterocycles

This work describes the application of Cu single-atom catalysts (SACs) for photocatalytic oxidative dehydrogenation of N-heterocyclic amines to the respective N-heteroaromatics through environmentally benign and sustainable pathways. The mesoporous graphitic carbon nitride (mpg-C₃N₄), prepared by the one-step pyrolysis method, possesses a lightweight material with a high surface area (95 m² g^-1) and an average pore diameter (3.6 nm). A simple microwave-assisted preparation method was employed to decorate Cu single-atom over mpg-C₃N₄ support. The Cu single-atom decorated on mpg-C₃N₄ support (Cu@mpg-C₃N₄) is characterized by various characterization techniques, including XRD, UV-visible spectrophotometry, HRTEM, HAADF-STEM with elemental mapping, AC-STEM, ICP-OES, XANES, EXAFS, and BET surface area. These characterization studies confirmed that the Cu@mpg-C₃N₄ catalyst exhibited high surface area, mesoporous nature, medium band gap, and low metal loading. The as-synthesized and well-characterized Cu@mpg-C₃N₄ single-atom photocatalyst is then evaluated for its efficacy in converting N-heterocycles into corresponding N-heteroaromatic compounds with excellent conversion and selectivity (>99 %). This transformation is achieved using water as a green solvent and a 30 W white light as a visible light source, demonstrating the catalyst's potential for sustainable and environmentally benign reactions.