Phosphomolybdic acid–reduced graphene oxide (PMoA–rGO) nanocomposites are fabricated by a photochemical reduction method. They are characterized by ultraviolet-visible spectra, scanning electron microscope images, Fourier transform infrared spectroscopy, Raman spectra and X-ray photoelectron spectroscopy in order to confirm that oxygen-containing functional groups on GO are replaced by PMoA and that GO is reduced to rGO in the photo-reduction process. The electrochemical properties of PMoA–rGO are investigated by cyclic voltammetry, which shows that the PMoA–rGO modified glassy carbon electrode has high electrocatalytic activity in acid solution via a fast, surface-controlled electron transfer process. The results indicate that the use of rGO not only increases the electroactive surface area, but also facilitates electron transfer due to its high electric conductivity.

ZnO is modified by Cu ₂ O by the process of precipitation and calcination. X-ray diffraction has shown that Cu ₂ O/ZnO catalysts are made of highly purified cubic Cu ₂ O and hexagonal ZnO. Scanning electron microscopy and transmission electron microscopy have shown that ZnO adhered to the surface of Cu ₂ O. Due to the doping of Cu ₂ O, the absorption range of the Cu ₂ O/ZnO catalyst is shifted from the ultraviolet to the visible region due to diffuse reflection. X-ray photoelectron spectroscopy and photoluminescence spectra have confirmed that there is a substantial interaction between the two phases of the resultant catalyst. The degradation efficiency of Cu ₂ O/ZnO on methyl orange solution is obviously enhanced compared to Cu ₂ O and ZnO. The maximum degradation efficiency is 98%. The degradation efficiency is affected by the pH of the solution and initial concentration. After three rounds of recycling, the degradation rate is almost same. This shows a consistent performance of Cu ₂ O/ZnO. The increase in catalytic ability is related to the lattice interaction caused by the doping of Cu ₂ O.