Elaboration of CuS nanomaterials via hydrothermal route: Examining physical properties and photocatalytic potential

The stable and efficient CuS photocatalyst was elaborated by the facile hydrothermal route at 140 °C for various durations, from copper chloride (CuCl2) and thiourea (SC(NH2)2) aqueous solutions. Characterization techniques such as X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) coupled with energy-dispersive of X-ray system (EDX) analysis, showed the formation of pure CuS nanomaterial. Electrochemical impedance spectroscopy (EIS) revealed that synthesized CuS exhibited a quick charge transfer at high frequencies and a diffusion or transport of ions from the electrolyte to the electrode surface at medium and low frequencies. Hall effect measurement indicated that all prepared CuS are a p-type semiconductors with a hole concentration on the order of 1020 cm−3. A decrease in the hole concentration with increasing heat treatment duration was observed and related to the healing of Cu vacancies. Transmittance and absorbance measurements showed that all samples interacted with light, exhibiting a prominent peak around 600 nm. Tauc method revealed an increase of the optical band gap values from 1.56 to 1.75 eV with the increment of heat treatment duration. Photocatalytic activity of CuS prepared at 140 °C for 16 h was determined by measuring the degradation rate of methylene blue (MB) dye under UV light in the absence and presence of hydrogen peroxide (H2O2). The results demonstrate CuS as a stable and efficient photocatalyst and underscore its potential for application in wastewater purification processes.