Mo‐Doped Mesoporous RuO2 Spheres as High‐Performance Acidic Oxygen Evolution Reaction Electrocatalyst

Abstract The development of highly active and acid‐stable electrocatalysts for oxygen evolution reaction (OER) is of great significance for water electrolysis technology. Herein, a highly efficient molybdenum‐doped mesoporous ruthenium dioxide sphere (Mo‐RuO 2 ) catalyst is fabricated by a facile impregnation and post‐calcination method using mesoporous carbon spheres to template the mesostructure. The optimal Mo 0.15 ‐RuO 2 catalyst with Mo doping amount of 15 mol.% exhibits a significantly low overpotential of 147 mV at 10 mA cm −2 , a small Tafel slope of 38 mV decade −1 , and enhanced electrochemical stability in acidic electrolyte, far superior to the commercial RuO 2 catalyst. The experimental results and theoretical analysis reveal that the remarkable electrocatalytic performance can be attributed to the large surface area of the mesoporous spherical structure, the structural robustness of the interconnected mesoporous framework, and the change in the electronic structure of Ru active sites induced by Mo doping. These excellent advantages make Mo‐doped mesoporous RuO 2 spheres a promising catalyst for highly efficient electrocatalytic OER in acidic media.