Growth and Characterization of Copper Zinc Tin Sulfide (CZTS), Molybdenum Disulfide (MoS₂) MoS₂, and CZTS/MoS₂ Nanocomposite Photocatalysts for Water Cleaning

Copper Zinc Tin Sulfide (CZTS) is a non-toxic, earth-abundant, and environmentally friendly semiconductor used in energy harvesting and photocatalysis due to its favorable optical band gap (~1.5 eV) and absorption coefficient (~104 cm-1). The low band gap of CZTS causes free charge carriers to recombine. Two-dimensional materials, such as molybdenum disulfide (MoS2) can be composited with CZTS to enhance carrier mobility and optical absorption properties across the solar spectrum, providing a promising solution for solar energy applications. In the present study, CZTS, MoS2, and hybrid CZTS/MoS2 nanocomposite were successfully synthesized using a facile hydrothermal method and systematically analyzed to investigate their structural, optical, photoluminescent, morphological characteristics, and photocatalytic dye degradation application. X-ray diffraction analysis confirmed the kesterite structure of CZTS and the hexagonal phase of MoS2, revealing diffraction patterns indicating both phases and confirming the formation of a heterojunction. The average crystallite sizes were determined to be approximately ~24 nm, ~40 nm, and ~27 nm for CZTS, MoS2, and CZTS/MoS2 nanocomposite, respectively. Field Effect Scanning Electron Microscopy images demonstrated spherical and layered morphologies for CZTS and MoS2, respectively, while the composite showed a cohesive and uniform distribution of CZTS nanoparticles across the MoS2 nanosheets. UV-Vis spectroscopy revealed increased light absorption and a decreased band gap in the CZTS/MoS2 composite, indicating better photon harvesting compared to individual materials. The photoluminescence study revealed a significant decrease in light emission from the CZTS/MoS2 nanocomposite, indicating effective charge separation and reduced recombination. This enhances photocatalytic activity and demonstrates the potential of CZTS/MoS2 nanocomposites for photocatalytic and environmental applications.