Bimetallic single-cluster catalysts anchored on graphdiyne for alkaline hydrogen evolution reaction

Abstract

Pt-based electrocatalysts suffer from high water dissociation barriers that limit their overall hydrogen evolution reaction (HER) activities in alkaline media. Here we predict the bimetallic four-atom single-cluster catalysts (SCCs) M1A3 (M as later transition metal and A as early transition metal) with pyramidal structure supported on graphdiyne (GDY) for alkaline HER. Theoretical calculations show that the stable Pt1Ti3/GDY SCC delivers high alkaline HER activity via the Volmer-Heyrovsky mechanism. The excellent catalytic performance of Pt1Ti3/GDY SCC is attributed to both the low-valent Pt site that renders an optimal hydrogen adsorption free energy (ΔG*H), and the synergic effect of adjacent Ti sites that leads to a low water dissociation barrier. By screening alternative M1 in M1Ti3/GDY for optimal ΔG*H and facile water dissociation, we further identify the Ir1Ti3/GDY SCC to be a potentially high-performing alkaline HER electrocatalyst at low *OH coverage. Our work provides new insights and guidelines for the rational design of alkaline HER electrocatalysts.