Enhanced ruthenium oxide-based OER catalyst by multicomponent acid-tolerant element doping

Developing advanced electrocatalysts for oxygen evolution reaction (OER) in acidic media remains a challenge due to the sluggish reaction kinetics and severe dissolution of RuO₂-based catalysts. Herein, we develop a dealloying-annealing strategy to prepare a kind of nanoporous RuO₂ with bimodal porosity and high specific surface area. Moreover, by doping different acid-tolerant metal elements, we can adjust the OER activity of the nanoporous RuO₂. The high content metal element doping also greatly enhances the utilization efficiency of Ru, resulting in a higher Ru-based mass activity. By screening different element combinations, we find the Fe, Cu, Mo, and Ti codoped RuO₂ (i.e., FeCuMoTi-RuO₂) shows the highest performance with an overpotential of 147 mV at 10 mA cm⁻² in 0.5 M H₂SO₄ solution, which is among the highest performance reported. The multicomponent doping also makes the nanoporous RuO₂-based catalyst highly stable during the 130 h testing at 10 mA cm⁻². Interestingly, the FeCuMoTi-RuO₂ is also highly active for hydrogen evolution reaction (HER) in the acidic media. Density functional theory calculations reveal that the modified electronic structure of Ru active sites by the dopants and the presence of Mo, Ti and Fe also contribute to the enhanced stability.