Synergistic photocatalysis: harnessing WSe 2 -ZnO nanocomposites for efficient malachite green dye degradation

In this work, the zinc oxide (ZnO) nanorods on the WSe 2 nanosheets were synthesized by a two-step method. The synthesized nanomaterials were characterized by XRD and SEM to confirm the structural and morphological properties. The band gap of the materials was calculated using a Tauc’ plot, and the band gap of the nanocomposite was found to be 2.59 eV. The nanocomposite falls under the visible light spectrum and overcomes the problem of wide bandgap of ZnO. The surface charge of the nanocomposite was analyzed by zeta potential measurement and found to be suitable for the adsorption of malachite green dye. The fabrication of nanocomposite improves the recombination rate, as confirmed by the time-resolved photoluminescence measurements. The photocatalytic degradation of malachite green dye was performed, and an efficiency of ~80% was achieved. The nanocomposite follows a pseudo-first-order model, which is confirmed by the high correlation coefficient value. The photocatalysis mechanism was proposed and confirmed through a scavenger test. The reusability test demonstrates that the nanocomposite is a potential candidate for dye degradation.