Interfacially regulated hierarchical Ni-based electrodes for selective electrocatalytic hydrogenation of biomass-derived platform molecules

Abstract

Electrocatalytic hydrogenation of biomass-derived oxygenates is limited by hydrogen evolution, acid-driven degradation of non-noble electrodes, and poor control of gas-evolving interfaces. Hierarchical Ni electrodes were prepared by dynamic hydrogen bubble templating on semiporous stainless steel and coupled with dodecyltrimethylammonium chloride (DTAC) interfacial regulation and Ru decoration. The macroporous, dendritic scaffold supports surface accessibility, reactant transport, and gas release, while DTAC attenuates unproductive proton reduction and improves structural persistence in acidic media. The platform was evaluated for levulinic acid (LA), 5-hydroxymethylfurfural (HMF), and furfural (FF), showing reactant-dependent selectivity. LA reduction was strongly temperature-dependent: 4-hydroxypentanoic acid-rich mixtures dominated at 5 °C, whereas γ-valerolactone (GVL) was favored at 50 °C, reaching 95.8% conversion, 88.7% Faradaic efficiency, and 92.6% GVL selectivity on DTAC-modified Ru-Ni A. HMF mainly yielded 2,5-bis(hydroxymethyl)furan, while FF gave furfuryl alcohol. Density functional theory calculations on clean Ni facets provide qualitative mechanistic context for possible surface-bound LA-to-GVL pathways and their sensitivity to surface geometry and reaction sequence.