Interfacial effect of mono (Cu, Ni) and bimetallic (Cu–Ni) decorated ZnO nanoparticles on the sunlight assisted photocatalytic activity

Mono/bimetals and their oxides are of significance as potential catalyst for various applications. Herein, we report the mono (Cu, Ni) and bimetal (Cu75Ni25) decorated zinc oxide ([email protected]) nanoparticles synthesised by hydrothermal method and their structural modifications upon partial or complete oxidation by thermal treatment at 400 °C and 600 °C. XRD and Raman spectroscopic analysis confirmed the presence of metal in as prepared condition while copper and nickel formed the corresponding oxides at 400 °C and 600 °C, respectively. A similar band gap energy was observed due to the presence of nanoparticles on the surface ZnO even after heat treatment. Among all the samples, [email protected] heat treated at 400 °C ([email protected]) showed the best photocatalytic activity in the degradation of methylene blue (MB) under the sunlight with a rate constant of about 0.502 min−1 and conversion efficiency of 98% in 40 min. A time-resolved photoluminescence study showed a higher lifetime value of 38.12 ns for [email protected] for electron-hole recombination. Compared to mono noble metals like Pt, Au, Ag etc., loaded over semiconductor, [email protected] showed five times faster degradation of MB under sunlight. This study shows the of the efficiency of cost-effective bimetallic over mono/noble metal decorated ZnO towards sunlight assisted photocatalysis.