Hydrogen Spillover Mechanism at the Metal-Metal Interface in Electrocatalytic Hydrogenation

Hydrogen spillover in metal-supported catalysts can largely enhance electrocatalytic hydrogenation performance and reduce energy consumption. However, its fundamental mechanism, especially at the metal-metal interface, remains further explored, impeding relevant catalyst design. Here, we theoretically profile that a large free energy difference in hydrogen adsorption on two different metals (|ΔG_H-metal(i)-ΔG_H-metal(ii)|) induces a high kinetic barrier to hydrogen spillover between the metals. Minimizing the difference in their d-band centers (Δϵ_d) should reduce |ΔG_H-metal(i)-ΔG_H-metal(ii)|, lowering the kinetic barrier to hydrogen spillover for improved electrocatalytic hydrogenation. We demonstrated this concept using copper-supported ruthenium-platinum alloys with the smallest Δϵ_d, which delivered record high electrocatalytic nitrate hydrogenation performance, with ammonia production rate of 3.45±0.12 mmol h^-1 cm^-2 and Faraday efficiency of 99.8±0.2 %, at low energy consumption of 21.4 kWh kg_amm ^-1. Using these catalysts, we further achieve continuous ammonia and formic acid production with a record high-profit space.