Optimizing Acidic\nOxygen Evolution with Manganese-Doped\nRuthenium Dioxide Assembly

Ruthenium dioxide (RuO<sub>2</sub>) is one of the promising\ncatalysts\nfor the acidic oxygen evolution reaction (OER). However, designing\nRuO<sub>2</sub> catalysts with good activity and stability remains\na significant challenge. In this work, we propose the manganese (Mn)-doped\nRuO<sub>2</sub> assembly as a catalyst for the OER with improved activity\nand stability. Consequently, the optimized 7% Mn-RuO<sub>2</sub> exhibits\nexceptional OER activity in 0.5 M H<sub>2</sub>SO<sub>4</sub>, delivering\na low overpotential of 195 mV to achieve a current density of 10 mA\ncm<sup>–2</sup>. Furthermore, it displays the highest mass\nactivity among all the tested catalysts, reaching 587.9 A g<sub>Ru</sub><sup>–1</sup> at 1.5 V versus the reversible hydrogen electrode\n(vs RHE), which is 7.8 and 139.8 times higher than those of undoped\nRuO<sub>2</sub> and commercial RuO<sub>2</sub>, respectively. Moreover,\n7% Mn-RuO<sub>2</sub> demonstrates remarkable stability over a continuous\noperation to 100 h (at 10 mA cm<sup>–2</sup>) without significant\nperformance attenuation. Additionally, theoretical calculations indicate\nthat Mn doping weakens the adsorption of the OER intermediates and\nmodifies the potential-determining step (PDS) of the OER, thereby\nreducing the OER overpotential. Consequently, strategies involving\nMn doping can effectively enhance the overall kinetics of the OER.\nThis work offers a promising approach for the design of efficient\nwater electrolysis catalysts.