Comparative Electrochemical, Photocatalytic, and Photoluminescence Studies in SrWO₄ and rGO-SrWO₄ Nanocomposites

SrWO₄ (SWO), reduced graphene oxide (rGO), and rGo-SrWO₄ (rGO-SWO) nanocomposite systems were synthesized through co-precipitation, the modified Hummers method, and sonochemical methods, respectively. Structural details were confirmed by standard x-ray diffraction (XRD), Raman spectroscopy, and Fourier transform infrared (FTIR) spectroscopy, representing the indicative rGO and SrWO₄ (SWO) features, respectively. All features were found together in the composite materials. Scanning electron microscopy (SEM) micrographs show excellent distribution of SWO nanoparticles on rGO flakes. UV–visible diffuse reflectance spectroscopy (UV–Vis–DRS) was implemented for band gap evaluation. The evaluated band gap energies increase with the increase in calcination temperature, and band gap energy is found to be in the range 4.00–4.33 eV for SWO and 3.06–3.32 eV for rGO-SWO nanocomposite. The rGO-SWO nanocomposite shows improved photocatalytic ability with 89% degradation of MB dye as compared to SWO. Photoluminescence (PL) studies indicate that the particle size plays a vital role in the PL excitation and emission intensities. The intensity of the spectra was observed to be decreased in the case of rGO-SWO composites, indicating the reduction in the recombination rate of e⁻-h⁺ pairs by the introduction of rGO. Electrochemical studies indicate that the rGO-SWO composite shows a twofold increase in specific capacitance as compared to the pristine SWO compounds.