Excellent photocatalytic performance of Zn(1−x)Mg_xO/rGO nanocomposites under natural sunlight irradiation and their photovoltaic and UV detector applications

Highlights: • Zn_{(1 − x)}Mg_xO/rGO nanocomposites and Zn_{(1 − x)}Mg_xO were synthesized by a sol-gel method. • The obtained samples were applied as photocatalyst, solar-cell, and UV detector materials. • Zn_{(1 − x)}Mg_xO/rGO showed excellent photocatalyst, photovoltaic performance, and fast response to UV illumination. Photocatalytic activity, photovoltaic, and UV detector applications of Zn_{(1 − x)}Mg_xO (x = 0.02, 0.04, and 0.06) nanoparticles (NPs) and Zn_{(1 − x)}Mg_xO/graphene nanocomposites were investigated. Graphene oxide (GO) sheets with a few layers were utilized as a graphene source, and the Zn_{(1 − x)}Mg_xO nanoparticles were synthesized and decorated on graphene oxide sheets by a simple sol-gel method. Transmission electron microscope (TEM) images and X-ray diffraction (XRD) patterns indicated that the Zn_{(1 − x)}Mg_xO NPs/GO nanocomposites had significantly smaller diameter and crystallite size compared to the Zn_{(1 − x)}Mg_xO NPs. Several techniques, including XRD, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, and Raman spectroscopy demonstrated that graphene oxide (GO) sheets reduced and changed into reduced graphene oxide (rGO) during the synthesis process. It was observed that the absorption peak of the Zn_{(1 − x)}Mg_xO/rGO nanocomposites was blue-shifted in comparison with the Zn_{(1 − x)}Mg_xO NPs. It was discovered that the Zn_{(1 − x)}Mg_xO/rGO nanocomposites showed an excellent performance to remove methylene blue (MB) dye under natural sunlight illumination compared to the Zn_{(1 − x)}Mg_xO NPs. Finally photodetector application of the samples under UV source illumination and photovoltaic performance of the samples were also investigated. It was observed a superior solar cell applications for the Zn_{(1 − x)}Mg_xO/rGO nanocomposites in comparison to the Zn_{(1 − x)}Mg_xO NPs.