Enhanced Hydrogen Evolution and Photocatalytic Performance of Graphene-Modified In0.2Cd0.8S Photocatalysts

An optimum In0.2Cd0.8S composition was synthesized with graphene to enhance photocatalytic performance. Graphene incorporation altered the morphology from compact grains to a loosely aggregated structure without affecting the crystal phase, as confirmed by XRD. XPS analysis indicated surface-level interaction between graphene and the In–Cd–S matrix, rather than lattice integration. Mott–Schottky and Kubelka–Munk analyses revealed n-type semiconducting behavior and a slight band gap increase from 2.46 to 2.51 eV upon graphene blending. UV–Vis and IPCE measurements showed enhanced light absorption, with IPCE values of 9.33% and 5.01% at 380 nm and 480 nm, respectively. The 3.85 wt% graphene-modified photocatalyst achieved a hydrogen evolution rate of 4.97 μmolh−1cm−2, more than triple that of pristine In0.2Cd0.8S. These enhancements are attributed to improved charge transport and interfacial activity provided by the graphene.