Tailoring the electronic structure of FeRu-NC for efficient electrochemical oxidative dehydrogenation of L-ascorbic acid

Biomass electrooxidation for coupled hydrogen production offers a promising route to overcome the sluggish kinetics and high energy cost of conventional water electrolysis. The electrocatalytic oxidation of L-ascorbic acid (AA) to high-value dehydroascorbic acid (DHA) is particularly attractive but requires efficient catalysts to facilitate the challenging two-step dehydrogenation process. Here, we report a FeRu-NC catalyst with excellent L-ascorbic acid oxidation reaction (AAOR) catalytic activity and selectivity. The FeRu-NC catalyst achieves a significantly lower overpotential of 10 mV at 10 mA•cm⁻² and delivers a high current density of 200 mA•cm⁻² at only 0.68 V vs. RHE, while maintaining stable operation for over 80 h. DHA is produced with high yield (~95%), selectivity (~97%), and Faradaic efficiency (~95%). XPS, XAFS studies and in-situ IR spectroscopy reveal that the introduction of trace Ru modulates the electronic structure of Fe single-atom sites, enhancing the adsorption of key intermediates and promoting the second dehydrogenation step, presenting a highperformance AAOR activity and high selectivity for DHA.