Motivating Ru-bri site of RuO₂ by boron doping toward high performance acidic and neutral oxygen evolution

The electrocatalysis of oxygen evolution reaction (OER) plays a key role in clean energy storage and transfer. Nonetheless, the sluggish kinetics and poor durability under acidic and neutral conditions severely hinder practical applications such as electrolyzer compatible with the powerful proton exchange membrane and biohybrid fuel production. Here, we report a boron-doped ruthenium dioxide electrocatalyst (B-RuO₂) fabricated by a facile boric acid assisted strategy which demonstrates excellent acidic and neutral OER performances. Density functional theory calculations and advanced characterizations reveal that the boron species form an anomalous B–O covalent bonding with the oxygen atoms of RuO₂ and expose the fully coordinately bridge ruthenium site (Ru-bri site), which seems like a switch that turns on the inactive Ru-bri site into OER-active, resulting in more exposed active sites, modified electronic structure, and optimized binding energy of intermediates. Thus, the B-RuO₂ exhibits an ultralow overpotential of 200 mV at 10 mA/cm² and maintains excellent stability compared to commercial RuO₂ in 0.5 M sulfuric acid. Moreover, the superior performance is as well displayed in neutral electrolyte, surpassing most previously reported catalysts.