Dual-mode environmental remediation of toxic dyes through chemo-catalytic and photocatalytic pathways using covellite (cus) nanosheet clusters

Clusters of high-purity Covellite (CuS) nanosheets with remarkable catalytic properties were synthesized by a simple mechanochemical process, which effectively addressed certain pitfalls of traditional solid-state synthesis, including hours-long grinding, the necessity of annealing to remove byproducts, and the hurdles in achieving crystallite sizes below 20 nm. The study of reaction mechanisms revealed the formation of an intermediate [Cu(tu)] Cl. 0.5 H2O, which acted as a self-sacrificial precursor for forming CuS nanosheets. The extensive characterization incorporating XRD with Rietveld refinement, HRTEM, FESEM, EDS, UV-VIS absorption, FTIR, and Raman Spectroscopy confirmed the formation of phase pure hexagonal CuS with stacked sheet-like morphology forming microflowers, with an average crystallite size of 11nm and having an optical band gap of 1.91 eV. Studies on the degradation of Methyl Orange (MO), a major environmental pollutant, using Covellite nanosheets as a dual catalyst had demonstrated remarkable efficiency, achieving 84% degradation in 12 minutes through chemo-catalysis and 89.5% in 40 minutes through photocatalysis. This study suggests ecofriendly and promising dual pathways to eliminate organic dye contamination by employing Covellite(CuS) nanocatalyst.