High-throughput screening of topological materials and differential electrochemical mass spectrometry validation establish FeCo as an earth-abundant catalyst for alkaline hydrogen evolution

Résumé fourni par la source

Electrolytic hydrogen production at scale requires catalysts that are abundant, mechanistically transparent, and verifiably active in alkaline media, where the absence of free protons couples hydrogen evolution to water activation and to a surface chemistry that is often redox-dynamic. In this regime, conventional voltammetry frequently conflates true HER currents with concurrent reduction of surface oxides and hydroxides, so both discovery and validation benefit from workflows that (i) restrict the materials space using physically motivated constraints, (ii) avoid redundant calculations during screening, and (iii) quantify hydrogen production directly at the product level. Here we combined high-throughput screening of topological materials with product-resolved electrochemistry to discover and validate FeCo as a non-noble-metal alkaline HER catalyst. Starting from eight earth-abundant bulk structures, the workflow generates reconstructed (001)/(110)/(111) slabs, enumerates symmetry-unique adsorption sites, and suppresses redundancy arising from symmetry-related terminations and from relaxation-driven convergence of distinct initial geometries to identical final states, compressing 2239 trial structures into 126 unique slabs and 227 unique adsorbate–surface systems. Using hydrogen adsorption energetics as a first-principles activity descriptor, 97 systems fall within the target window, with FeCo distinguished by H adsorption energies spanning a catalytically relevant range across all three facets (−0.58 to 0.02 eV). Guided by this ranking, FeCo was synthesized and examined under alkaline conditions. Operando-consistent surface chemistry was established by spectroscopy, revealing an oxide/hydroxide skin over a metallic core that explains the strong overlap between surface redox features and cathodic currents in cyclic voltammetry. Differential electrochemical mass spectrometry (DEMS) isolated the genuine HER signal ( m / z = 2), placing the onset at more positive potentials than inferred from voltammetry and yielding a reproducible Tafel slope of ∼77 mV dec −1 , indicative of mixed Volmer–Heyrovsky control. The exclusive H 2 signal and short-term steadiness establish a clean kinetic benchmark for an earth-abundant system, whereas attenuation under extended polarization traces to morphological evolution and partial loss of catalyst adhesion rather than loss of selectivity, identifying clear engineering routes for stabilization. By explicitly addressing water activation, redox-dynamic surfaces, and duplication control, this screening-to-validation pipeline validates FeCo as an Earth-abundant catalyst for alkaline HER and defines a general strategy for rapid discovery and mechanistic verification of sustainable, earth-abundant catalysts.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.