Enhanced catalytic activity of CuO/Cu2O hybrid nanowires for reduction of 4-nitrophenol in water

Abstract

Fabrication of hybrid nanostructured catalysts has emerged as a current trend for efficient treatment of wastewater. In this work, a simple wet chemical approach was used for the synthesis of CuO/Cu2O hybrid nanowires with low-cost copper acetate as a precursor. The morphology, crystallite size, crystal phase, surface area, and optical properties of the as-synthesized CuO/Cu2O hybrid nanowires were studied by transmission electron microscopy (TEM), high-resolution TEM (HRTEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller analysis, photoluminescence spectroscopy, and UV–visible absorption spectroscopy. The formation of CuO/Cu2O hybrid nanowires was clearly revealed by TEM and SEM studies. HRTEM, XRD, and XPS analyses identified the formation of CuO/Cu2O hybrid nanowires. The CuO/Cu2O hybrid nanowires were found to be extremely efficient catalysts for the complete reduction of toxic 4-nitrophenol in water to very useful 4-aminophenol in just 4 min. The enhanced catalytic efficiency of the CuO/Cu2O hybrid nanowires is attributed to their large surface area and enhancement of the charge separation due to the presence of heterojunctions. A possible mechanism for the reduction of 4-nitrophenol to 4-aminophenol is also proposed.