Cu ₂ O@rGO Nanocomposite for Dual Photocatalytic and Sensing Applications

We report a facile, one-pot synthesis of Cu2O@rGO nanocomposite, where 5 ± 2 nm Cu2O nanoparticle NPs are uniformly deposited on the reduced graphene oxide (rGO) sheets. In this process, simultaneous reduction of graphene oxide (GO) to rGO and copper hydroxide to Cu2O was performed in a single step using hydroxylamine as a reducing agent. This material exhibits efficient dual functionality, serving as a photocatalyst for the reduction of toxic Cr(VI) to Cr(III) under visible-light irradiation and nonenzymatic electrochemical sensing of glucose molecules. The rGO as a support material helps in increasing photo- or electrocatalytic reaction rate by reducing band gap and agglomeration of Cu2O particles, reducing the recombination rate of photogenerated excitons, and increasing transfer of photo- or electrogenerated electrons. The study of reduction mechanism reveals the reduction reaction occurs through direct electron transfer from conduction band to Cr(VI) molecules. During the electrochemical sensing, Cu(I) oxidizes to Cu(III) and then Cu(III) oxidizes glucose to gluconic acid; the process is highly selective in the presence of bioactive compounds (ascorbic acid, uric acid, dopamine, and NaCl) present in blood.