Comparative Study of pure and rGO-Integrated CaWO

Well-crystallized rGO-CWO nanocomposites were synthesized through an ultrasonic-assisted modified Hummer's method. The synthesized nanocomposite displayed improved photocatalytic activity compared to the pristine CWO nanoparticles. XRD patterns confirmed the single-crystal Scheelite structure of the as-prepared CWO nanoparticles. SEM micrographs reveal the formation of a spherical-like morphology for the CWO nanoparticles and their appropriate distribution on rGO flakes. A band gap reduction for rGO-CWO nanocomposite (~2.70 eV) compared to CWO nanoparticles (~4 eV) was observed from the UV-visible DRS (diffusive reflectance spectroscopy) studies, suggesting the increased photocatalytic activity of the nanocomposite. The lower intensity in the photoluminescent spectra of rGO-CWO nanocomposites at 350nm confirms the low rate of recombination of photogenerated electron-hole pairs due to the presence of the rGO matrix. The rGO-CWO nanocomposite showed almost 2-fold specific capacitance and quicker charge transfer than pristine CWO. The specific capacitance of rGO-CWO nanocomposite is observed as 544 F/g at current density of 1 A/g. This can be attributed to higher porosity and increased surface area due to the integration of rGO. The rGO-CWO nanocomposite delivered overall superior electrochemical properties compared to pristine CWO.