Photocatalytic hydrazine-assisted reduction of nitroarenes promoted by Cu dopant modulated In2S3 under ambient conditions

Abstract

The efficient reduction of nitroarenes to the corresponding amines is of great significance in the chemical industry. However, the conventional thermocatalysis route usually involves harsh reaction conditions (e.g., high temperature, pressurized hydrogen, and anaerobic atmospheres) and relies on precious metals or long reaction times. Herein, we cast an alternative protocol with a Cu-doped In₂S₃ (Cu/In₂S₃) semiconductor for the photocatalytic CO₂ emission-free hydrogenation of nitroarenes. Density functional theory (DFT) simulations and in situ characterization results demonstrate that Cu doping in In₂S₃ introduces intermediate energy levels and that the doped Cu site serves as a trapping site for photogenerated holes, prolonging the lifetime of charge carriers and optimizing the adsorption capacity of the reactants. The above features, combined with strong energy band coupling between photoactive Cu/In₂S₃ and carbon-free hydrazine as a hole scavenger, enable efficient and environmentally friendly (without carbon emission) photocatalytic hydrogenation of nitroarenes under ambient conditions (without inert gas protection) and visible light irradiation. In addition, the current hydrogenation system shows a broad reaction scope, good stability, and easily recyclable and scalable traits, demonstrating great practical potential.