Green synthesis of CuFeS₂ nanoparticles using mimosa leaves extract for photocatalysis and supercapacitor applications

We successfully synthesized CuFeS₂ nanoparticles (NPs) using a simple synthesis method mediated by touch me not (Mimosa pudica) leaves extract. X-ray diffraction (XRD) was used to analyze the structural properties, and it shows that the CuFeS₂ NPs have a tetragonal structure and quasi-pyramidal NPs of an average crystallite size of 31.0 nm with a secondary phase of few minor peaks of covellite (CuS). The optical characterization showed that CuFeS2 NPs have band gap energy ranges of 1.98–2.46 eV for different annealing temperatures. The electrochemical properties of the CuFeS₂ NPs were investigated using cyclic voltammetry (CV), galvanostatic charge discharge (GCD), and electrochemical impedance spectroscopy (EIS). An appreciable value of specific capacitance of 501.4 F/g was obtained at a scan rate of 10 mV/s for the CuFeS₂ NPs annealed at 250 °C which can be said to be within the optimum ideal annealing temperature for CuFeS₂ NPs. The CuFeS₂ NPs was used in the photodegradation of methylene blue (MB) under of solar irradiation. The highest rate constant of 3.1 × 10⁻² min⁻¹ and degradation efficiency of 98% were obtained for the unannealed CuFeS₂ NPs with good stability after three cycles. Therefore, the synthesized CuFeS₂ NPs were obtained using a Mimosa pudica leaves extract prospective application in both electrochemical energy storage devices and treatment of water contaminants. GO was added to increase the active sites for these ions, surface area, and conductivity of these electrodes for enhanced supercapacitive performance.