Self-assembly of cuprous oxide nanoparticles supported on reduced graphene oxide and their enhanced performance for catalytic reduction of nitrophenols

Abstract

Self-assembled cuprous oxide nanoparticles supported on reduced graphene oxide are synthesized by a chemical reduction method in aqueous systems. The results of field emission scanning electron microscopy and transmission electron microscopy demonstrate that the obtained sample features a hollow ball structure through the self-assembly. Moreover, the cuprous oxide particles dissociate into tiny lamellar structures with a diameter of 3 nm in an aqueous medium. The catalytic activity of the sample was investigated using the reduction of nitrophenols to aminophenols with excess sodium borohydride as the model reaction. The kinetics of reduction was proved to follow pseudo first order kinetics. The rates of catalytic reduction of nitrophenols have been found to follow the sequence: 2-nitrophenol > 4-nitrophenol > 3-nitrophenol, and the activation energies are 50.17 kJ mol⁻¹, 79.92 kJ mol⁻¹ and 63.86 kJ mol⁻¹ for 2-nitrophenol, 3-nitrophenol and 4-nitrophenol, respectively. In addition, the reusability of the Cu₂O/RGO compounds was also studied and the results showed that the compounds could be reused many times with nearly invariable high catalytic efficiency.