Mo, B-induced local structure and electron redistribution of RuO₂ for efficient acidic oxygen evolution

Oxygen evolution reaction (OER) is a key reaction in proton exchange membrane water electrolyzers (PEMWEs). Therefore, developing cost-effective acid-stable electrocatalysts to drive efficient OER is crucial. Here, we constructed a RuO₂ electrocatalyst (MoB-RuO₂) co-doped Mo and B atoms, which exhibits excellent OER performance in acidic media. In 0.5 mol/L H₂SO₄, MoB-RuO₂ exhibited a very low overpotential (166 mV) and could be operated stably for more than 550 h at 10 mA/cm² current density without significant loss of activity. More than 240 h of stable operation at 200 mA/cm² current density was achieved when using MoB-RuO₂ as a PEMWE anode. Experimental and theoretical results demonstrated that the excellent OER activity and stability of MoB-RuO₂ mainly originated from the incorporation of B atoms leading to the coordination unsaturation of the active centre Ru, and the simultaneous doping of Mo and B atoms modulated the electronic structure of Ru, which lowered the covalency of the Ru-O bond, thus making the catalyst exhibit excellent stability.