The rational design of hydrogen evolution reaction electrocatalysts that can compete with platinum is an outstanding challenge in the process of designing viable power-to-gas technologies. Here, we introduce delafossites as a family of hydrogen evolution reaction electrocatalysts in acidic media. We show that, in PdCoO₂, the inherently strained Pd metal sublattice acts as a pseudomorphic template for the growth of a tensile-strained Pd-rich capping layer under reductive conditions. The surface modification ranges up to 400 nm and continuously improves the electrocatalytic activity by simultaneously increasing the exchange current density and by reducing the Tafel slope down to 38 mV dec⁻¹, leading to overpotentials η₁₀ < 15 mV. The improved activity is attributed to the operando stabilization of a β-PdH_x phase with enhanced surface catalytic properties with respect to pure or nanostructured palladium. These findings illustrate how operando-induced electrodissolution can be used as a top-down design concept through the strain-stabilized formation of catalytically active phases.

可以与铂竞争的氢生成反应电催化剂的合理设计是设计可行的燃气技术的过程中面临的一项严峻挑战。在这里，我们介绍了铜铁矿作为酸性介质中氢气释放反应的电催化剂家族。我们显示，在PdCoO _2中，固有应变的Pd金属亚晶格充当还原条件下拉伸应变富Pd盖层生长的拟晶模板。表面改性范围可达400nm，并且通过同时增加交换电流密度和通过降低塔菲尔斜率下降到38毫伏癸不断改进的电催化活性^-1，导致超电势η ₁₀ <15毫伏。该改进的活性归因于β-PDH的operando稳定_X具有增强的表面的催化性能相对于纯的或纳米结构化钯。这些发现说明如何通过应变稳定地形成催化活性相，将操作性电溶解法用作自上而下的设计概念。