Surface Hydroxylated Mn-Doped RuO2 as an Efficient and Stable Electrocatalyst for Acidic Oxygen Evolution Reaction

The role of surface hydroxylation in the performance of RuO 2 -based electrocatalysts for oxygen evolution reaction (OER) is crucial but still unclear. Using first-principles calculations, we comprehensively studied the impact of surface hydroxylation states on the activity and stability of Mn-doped RuO 2 -based electrocatalysts (denoted as n OH-Mn 0.1 Ru 0.9 O 2, n = 1–5) in acidic OER. It was revealed that the moderately hydroxylated Mn 0.1 Ru 0.9 O 2 demonstrates better performance than the fully hydroxylated structure, and 4OH-Mn 0.1 Ru 0.9 O 2 holds the lowest reaction barrier of 0.14 eV in solvation under the constant potential of 1.5 V, which is lower than those of both pure RuO 2 (0.28 eV) and Mn 0.1 Ru 0.9 O 2 (0.23 eV). Such an increase in catalytic activity stems from the nonstrong-and-nonweak charge transfer of reaction sites. In addition, the synergistic effect of doping and hydroxylation can also increase the stability of RuO 2 through inhibition of structure collapse caused by the dissolution of Ru and the loss of lattice oxygen. The present study has provided a novel strategy for the design of efficient and stable RuO 2 -based acidic OER catalysts through surface hydroxylation.