One-pot, self-assembled hydrothermal synthesis of 3D flower-like CuS/g-C₃N₄ composite with enhanced photocatalytic activity under visible-light irradiation

Novel visible-light-driven 3D flower-like CuS/g-C₃N₄ composites have been synthesized by different wt% of CuS using hydrothermal method and characterized by standard analytical techniques such as XRD, FTIR, XPS, BET, UV–Vis DRS spectroscopy, SEM–EDS, and TEM. SEM and TEM analyses showed an intimate interfacial contact between flower-like CuS and g-C₃N₄ sheet. The synthesized composite materials (CuS/g-C₃N₄) showed excellent photocatalytic activity for the decolorization of methylene blue (MB) in aqueous suspension under visible-light irradiation, compared with pure CuS and g-C₃N₄. Among various composites of CuS/g-C₃N₄, 10 wt% of CuS showed highest photocatalytic activity for the decolorization of dye (MB). This remarkably improved photocatalytic performance of the synthesized materials could be attributed to the synergistic interaction between CuS and g-C₃N₄, leading to prolonged lifetime of photo-generated e^– and h⁺ pair through the Z-scheme system. A probable Z-scheme mechanism explaining the origin of enhanced performance of the composite material has been proposed. This work not only provides a facile way to synthesize 3D flower-like heterostructure, but also renders rational design for the development of highly efficient Z-scheme photocatalytic systems.