A noble bimetal oxysulfide CuOS catalyst for highly efficient catalytic reduction of 4-nitrophenol and organic dyes.

A novel copper-vanadium bimetallic oxysulfide (CuOS) nanoparticle catalyst was successfully synthesized by a facile method. The samples were characterized by X-ray photoelectron spectrometry (XPS), X-ray diffractometry (XRD), field-emission scanning electron microscopy (FE-SEM), UV-Vis diffuse spectroscopy (DRS), Fourier transform infrared spectroscopy (FTIR), and N adsorption-desorption isotherms. In order to check the catalytic efficiencies toward reduction reaction, 4-nitrophenol (4-NP) and other organic dyes such as rhodamine-B (RhB), methylene blue (MB), and methyl orange (MO) were used. The results showed that the CuOS prepared in the presence of a suitable amount of NH during the synthesis of the nanoparticles exhibited the fastest reduction capabilities by using NaBH as a reducing agent. It was demonstrated that a 100 mL 4-NP (20 ppm) solution was completely reduced by 5 mg CuOS-3 within 2 min. Moreover, the complete reduction of 100 mL of MO, RhB, and MB solutions of 100 ppm was also achieved by 5 mg CuOS-3 within 2 min, 6 min, and 5 min, respectively. Hence, the CuOS is an efficient catalyst for reducing 4-NP and organic dyes and can have great potential for industrial application.