Photochemical HER activity of layered metal phospho-sulfides and -selenides

Abstract

Monometallic and bimetallic layered phosphosulfides and phosphoselenides, prepared by high temperature solid state reactions, have been subjected to exfoliation to obtain few-layer materials. The photochemical HER activity of these materials has been investigated. Among the ternary MPS₃, the nickel compound exhibits the highest HER activity (2.6 mmol h⁻¹ g⁻¹), while MnPS₃, ZnPS₃ and CdPS₃ exhibit low activity, due to their large band gaps and presence of long P–P and M–S bonds. Amongst phosphoselenides, FePSe₃ shows a higher HER activity of 1.7 mmol h⁻¹ g⁻¹ than the Mn and Cd compounds. The quaternary phosphochalcogenide, Ag_0.5In_0.5PS₃, shows a high photochemical HER activity of 1.9 mmol h⁻¹ g⁻¹.