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

Abstract

Biomass electrooxidation coupled with 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 an 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 (FE) (∼95%). XPS and 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 high AAOR activity and high selectivity for DHA.