Non-precious metal single-atom loading and further strain engineering on SrTiO3 (100) surface for optimizing hydrogen evolution reaction

Single-atom loading of the non-precious transition metals (M = Ti, V, Mn, and Fe) on the (100) surface of SrTiO3 (STO) was theoretically investigated to evaluate the hydrogen evolution reaction (HER) with Gibbs free energy for hydrogen adsorption (∆GH*). V1-STO stood out owing to the ∆GH* of − 0.08 eV, which was competitive to the metallic Pt with the value of − 0.09 eV. The d band center rationalized well the primary screening of single-atom non-precious transition metals on STO. Furthermore, strain engineering was applied to refine the HER performance of V1-STO. The tensile strain increased the ∆GH*, while the compressed strain decreased the ∆GH*. A new descriptor of the d orbital splitting (εd−gap) was proposed to explain the optimization of the HER performance arising from the surface strains. This work conceives a combinational strategy to evaluate the HER performance, and may give guidance for the sequential design of HER catalysts.