Electronic structure engineering of ultradispersed Ru in NiO nanobricks for selective and efficient ethanol...

Integrating the ethanol oxidation reaction (EOR) into hybrid water-splitting systems presents a dual advantage of reducing anodic overpotentials and co-generating high-value chemicals. Nevertheless, the rational design of catalysts that reconcile high noble-metal atom economy with robust durability remains a formidable task. Here, we report a nanobrick-structured NiO electrocatalyst decorated with highly dispersed Ru species supported on nickel foam (Ru-NiO/NF), in which no Ru nanoparticles or clusters were detected. The catalyst was synthesized via a hydrothermal process followed by ion exchange. The introduction of Ru into the NiO host lattice effectively modulates the local electronic configuration and accelerates charge-transfer kinetics, while simultaneously regulating surface hydroxyl species (OH*) and expanding the electrochemically active surface area. Benefiting from these interfacial synergies, the optimized Ru₂-NiO/NF delivers current densities of 10 and 100 mA cm^-2 at low potentials of 1.08 ± 0.01 V and 1.34 ± 0.02 V, respectively, in 1.0 M KOH containing 0.5 M ethanol, thus outperforming pristine NiO/NF. The catalyst also achieves an acetate selectivity of 96.1 % and a Faradaic efficiency (FE) of 93.8 %. Complementary experimental evidence and density functional theory (DFT) calculations elucidate that the robust electronic coupling between Ru and Ni centers optimizes the adsorption energetics of key intermediates, thereby lowering the kinetic barriers for selective ethanol-to-acetate conversion. This work offers insights into the precise manipulation of electronic states in hybrid oxides for efficient, value-added electrocatalytic applications.