Organic substrate oxidation-driven water electrolysis enabled by Ru-loaded Mn₂O₃ nanoparticles for energy-efficient...

Transforming the inefficient oxygen evolution reaction (OER) by integrating beneficial organic substrate oxidation reactions offers an innovative way to significantly lower the energy requirements of water electrolysis while simultaneously producing valuable chemicals. This study introduces a ruthenium-loaded manganese oxide electrocatalyst (Ru-Mn₂O₃-U), synthesized through a rapid urea-assisted redox method. This approach not only ensures an even distribution of ruthenium, preventing harmful particle densification, but also creates easily accessible active centers on the surface, thereby enhancing both mass and charge transfer kinetics. The Ru-Mn₂O₃-U catalyst demonstrates exceptional performance, achieving current densities of 100 mA cm^-2 and 400 mA cm^-2 at potentials of 1.32 V and 1.45 V versus the reversible hydrogen electrode (RHE) during the ethylene glycol electrooxidation reaction (EGEOR). With a specific mass activity of 108.4 A g^-1 and a surface-specific activity of 0.325 mA cm^-2, it demonstrates an impressive faradaic efficiency of 91.8% by primarily converting ethylene glycol (EG) into glycolate. In practical applications, the EG-assisted electrolyzer, comprising a Ru-Mn₂O₃-U‖Ru-Mn₂O₃-U cell, reaches a current density of 100 mA cm^-2 at just 1.54 V, showcasing a hydrogen faradaic efficiency of around 93% along with good durability. By effectively combining hydrogen production with the oxidation of biomass-derived alcohols, this approach enhances the energy efficiency of electrochemical hydrogen generation, paving the way for a sustainable energy future.