First-principles study of non-metallic doping and noble metal loading on ZnIn2S4 semiconductor photocatalyst

Abstract

Zinc Indium Sulfide (ZnIn₂S₄, ZIS) is recognized as a promising semiconductor photocatalyst for widely applications such as water splitting for hydrogen production, due to its non-toxicity, proper band gap and strong visible light absorption. However, it still faces challenges including moderate intrinsic activity and limited active site number. Herein, this work studied the photocatalytic performance of hydrogen evolution reaction (HER) in the ZIS with non-metallic elements doping and modified with Pd atomic cocatalysts through first-principles calculation. The results show that the catalytic activity of the ZIS(0 0 1) basal surface is improved when doped with B, C, F, Si, P, Cl, Se, Br, Te, or I, among which Si doping shows the most significant improvement in intrinsic catalytic activity. Further enhancement is observed by loading Pd atom onto the Si-doped ZIS(0 0 1) surface to create the Pd@Si-ZIS(0 0 1) structure, leading to increased active surface sites and intrinsic catalytic activity. Comparison with S sites on the Si-ZIS(0 0 1) basal plane shows that the hydrogen adsorption free energies of S sites on the Pd@Si-ZIS(0 0 1) basal plane approach 0 eV (0.072 eV and 0.074 eV), resulting in an enhanced catalytic performance. Moreover, the Pd sites on the Pd@Si-ZIS(0 0 1) basal plane are activated, and exhibit a superior catalytic activity beyond single Pd loading.