Mn-Doped RuO₂ Nanocrystals as Highly Active Electrocatalysts for Enhanced Oxygen Evolution in Acidic Media

Abstract

Currently, RuO2 is a benchmark acidic oxygen evolution reaction (OER) catalyst. Nevertheless, its wide applications are always restricted by slow dynamics and limited durability. This paper reports a type of Mn-doped RuO2 nanocrystals for boosting the OER catalytic performance in acidic media. The catalyst (named Mn-RuO2) is prepared through annealing of Ru-exchanged Mn-based derivative at 300 °C. Such Mn-RuO2 exhibits excellent acidic OER activity, with an overpotential of 158 mV at 10 mA cm–2 and a stability of 5000 cycles in the presence of sulfuric acid (0.5 mol/L). Both structural characterization and theoretical analysis show that the Mn doping in RuO2 can tune the d-band center of Ru active sites and lower antibonding surface-adsorbate states, which leads to a decreased free energy of the rate-determining step, ultimately enhancing the intrinsic activity of RuO2.