Metal oxide plating for maximizing the performance in ruthenium(IV) oxide-catalyzed electrochemical oxygen evolution reaction

Hydrogen production by proton exchange membrane water electrolysis requires the anode with low overpotential for oxygen evolution reaction (OER) and robustness in acidic solution. While exploring new electrode materials to improve the performance and durability, optimizing the morphology of typical materials using new methods is a big challenge in materials science. RuO2 is one of the most active and stable electrocatalysts, but further improvement in the performances and cost reduction must be achieved for practical use. Here we present a novel technology “metal oxide plating” that can provide maximum performances with minimum amount. A uniform single-crystal RuO2 film with thickness of ~2.5 nm by a solvothermal-post heating method at theamount (x) of only 18 μg cm−2 (ST-RuO2(18)//TiO2 NWA). OER stably proceeds on ST-RuO2(18)//TiO2 NWA with ~100% efficiency to provide mass-specific activity (MSA) of 341 A g−1catal at 1.50 V (vs. RHE) exceeding the values for most of the state-of-the-art RuO2 electrodes.