Catalytic hydrogen evolution on CdZnS system: Dragging the synergy between Ni dopants and Ag cocatalysts†

Abstract

Hydrogen has potential to be utilized as clean and sustainable fuel to meet increasing energy demands. In current study, photocatalytic hydrogen evolution performances of CdZnS (CZS) have been improved by incorporation of Ni and Ag metals. Hydrothermal and chemical reduction approaches were utilized to synthesize Ag@Ni−CZS catalysts. The synthesized photocatalysts were characterized by XRD, SEM equipped with EDX, FT−IR, BET, UV−Visible/DRS, X-rays photoelectron spectroscopy (XPS), PL spectroscopy, and electrochemical techniques. The results suggest that Ni and Ag supported CZS catalysts have better charge separation and defects that lead to enhanced catalytic performances. Under optimized conditions, rate of H₂ evolution for Ag@Ni−CZS catalyst is 14.13 mmol g⁻¹ h⁻¹ (with apparent quantum efficiency of 25.60 %) which is 4.8 times higher than pure CZS (2.91 mmol g⁻¹ h⁻¹). Enhanced photocatalytic performance exhibited by Ag@Ni−CZS is due to synergistic effect of Ag cocatalyst and Ni dopant. Ag contents provides hot electrons through SPR induction and these electrons were quenched by Ni dopant to generate hydrogen. To find optimised rate of hydrogen evolution, various parameters like pH, catalyst dose, concentration of sacrificial reagent and power intensity have been examined.