Synthesis of Composition Tunable and (111)-Faceted Cu/Cu2O Nanoparticles toward Photocatalytic, Ligand-Free, and Solvent-Free C–N Ullmann Coupling Reactions

A novel protocol has been demonstrated for the preparation of composition tunable (111)-faceted Cu/Cu2O nanoparticles, an interesting shape evolution of nanoparticles, from octahedron, tetrahexahedron, and finally, star-shaped nanostructures, was achieved by increasing the amount of glucose in the reaction. The prepared Cu/Cu2O nanoparticles can be used for the photocatalysis of the C–N Ullmann coupling reaction without the use of ligands and solvents. By the design of the Cu/Cu2O nanoparticles with a tetrahexahedron structure, the reaction productivity achieves 77%. Goals of reduction of energy consumption and environmentally friendly chemical processes have thus been met. As illustrative examples, these Cu/Cu2O nanoparticles are used to achieve high photocatalytic activity for both aliphatic amine and cyclic amine reacting with halogenated benzene.