Hydrogen spillover in complex oxide multifunctional sites improves acidic hydrogen evolution electrocatalysis

Abstract Improving the catalytic efficiency of platinum (Pt) for hydrogen evolution reaction (HER) is crucial for water splitting technologies, and hydrogen spillover has emerged as a new frontier in designing the binary-component Pt/support HER electrocatalysts. However, such binary catalysts always suffer from long reaction pathway, undesirable interfacial barrier, and complicated synthesis processes. Here we report a single-phase complex oxide La2Sr2PtO7+δ as a high-performance HER electrocatalysts in acidic media via a unique atomic-scale hydrogen spillover effect between multifunctional catalytic sites. With insights from theoretical calculations, a possible synergistic mechanism involving the hydrogen spillover channel from OLa site→La-Pt bridge site→Pt site is proposed; namely, the OLa site enriches proton, the La-Pt bridge site with thermo-neutral H* adsorption facilitates the hydrogen spillover and H2 generation, and Pt site favors the final H2 desorption. Benefiting from such unusual phenomenon, the resulting La2Sr2PtO7+δ exhibits an exceptional HER electrode activity with low overpotential of 13 mV at 10 mA cm− 2 and small Tafel slope of 22 mV dec− 1, and significantly enhanced intrinsic activity and durability than commercial Pt black catalyst.