Comparative Study of pure and rGO-Integrated CaWO₄ Nanoparticles: Photocatalytic Efficiency for Dye Degradation and Electrochemical Properties

¹ Department of Physics, Kakatiya University, Warangal 506009, Telangana India
² Department of Pure & Applied Physics, Guru Ghasidas Vishwavidyalaya, Bilaspur 495009, India
³ Interface Lab, Department of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul 05006, Republic of Korea

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Published online: 5 March 2026

Abstract

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.