Investigation of structural, optical, thermal, and chemocatalytic properties of chemically synthesised Covellite (CuS) nanoparticles

Abstract Covellite (CuS) nanoparticles were synthesised using a chemical precipitation method with copper chloride and thiourea, without any surfactants. Various techniques such as XRD, HR-TEM, FE-SEM, UV-Vis spectroscopy, TGA, BET, and EDS confirmed the appearance of hexagonal CuS nanostructures having crystallite dimension averaging 3.7 nm, displaying flake-like morphology, possessing an energy gap of 2.1 eV, and favourable surface porosity characteristics. The phase transitions of the Covellite nanoparticles at 300°C, 500°C, and 800°C resulted in the formation of Cu 2 S, CuSO 4 , and CuO nanoparticles respectively, and the observed annealing mechanisms aligned with the TGA analysis. The chemo-catalytic efficiency of CuS was evaluated in the breakdown of Methylene blue using Sodium borohydride, achieving 93.48 % degradation within 21 minutes. The degradation process followed pseudo-first-order kinetics, consistent with the Langmuir-Hinshelwood approach, with a rate constant of 0.1206 min −1 , showcasing the potential of CuS nanoparticles for rapid and efficient degradation of harmful organic dyes, offering a promising approach to address environmental pollution