Enhanced Photocatalytic Hydrogen Evolution Properties of Er-Doped ZnIn2S4 Nanostructures via Hydrothermal Synthesis

The utilization of ZnIn2S4 in photocatalytic hydrogen applications has garnered immense interest due to its promising features encompassing non-toxic nature, suitable band gap, and robust stability. However, the performance of ZnIn2S4 remains constrained by its limited absorption range and swift charge recombination. In this context, doping with rare earth metals has emerged as a potential strategy to enhance photocatalytic efficiency, yet this approach remains understudied. Herein, we report the synthesis of Er-doped ZnIn2S4 nanostructures utilizing a hydrothermal method, followed by structural characterization and HER evaluations. The XRD analysis confirms the primarily hexagonal crystal structure of ZnIn2S4. Notably, an optimal Er concentration of 70% exhibits enhanced hydrogen production efficiency. This improvement is attributed to the efficient charge transfer facilitated by Er doping, as evidenced by the photocurrent and Nyquist plots of ZnIn2S4. Moreover, the introduction of new energy levels by Er in the band gap enhances the light harvesting capability of ZnIn2S4. Furthermore, SEM studies reveal that Er doping influences the crystal growth rate of the material. [GRAPHICS]