Synthesis of copper oxide/reduced graphene oxide nanocomposite and its enhanced catalytic activity towards reduction of 4-nitrophenol

Abstract

Graphene oxide (GO) and its derivatives have attracted extensive interest in many fields, including catalytic chemistry, organic synthesis, and electrochemistry. Integrating nanoparticles into GO enhances the properties and functionality of the nanocomposites due to the synergetic effects between GO nanosheets and the nanoparticles. A facile and novel hydrothermal method of preparing copper oxide–reduced graphene oxide (CuO–rGO) nanocomposites has been developed. The nanocomposites were prepared from a mixture of GO and cuprous chloride (CuCl). In this method simultaneous formation of CuO and reduction of GO takes place without using any foreign materials. The synthesized composites were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) spectroscopy. 4-Nitrophenol (4-NP) was used as a probe to assess the catalytic activities of the prepared CuO–rGO nanocomposites. The nanocomposites exhibited excellent and stable catalytic activity towards reduction of 4-NP to 4-aminophenol (4-AP) in the presence of NaBH₄. The catalytic activities of the nanocomposites were also studied by changing the ratio of GO and Cu. The reaction kinetics followed a pseudo-first-order rate law and the maximum value of the rate constant is 13.951 min⁻¹, which is superior to all other reported works. The catalyst can be easily regenerated and reused with good recyclability even for up to five catalytic cycles.