Ni–Co Codoped RuO₂ with Outstanding Oxygen Evolution Reaction Performance

Synthesizing oxygen evolution reaction (OER) catalysts with high activity by codoping has been proven to be feasible for effectively using noble metals via renewing their basic properties. Here, we prepare two series of Ru based codoped catalysts Ni_xCo_yRu_1–x–yO₂ with outstanding OER activity compared with RuO₂, one of the state-of-the-art OER catalysts. The molar ratio of case dopants, nickel and cobalt, is regulated from 1:1 to 1:1.5 for the host structure RuO₂ as the main variable. The synthesized codoped RuO₂ with Co/Ni of 1.5 reflected a Tafel slope of only 32 mV dec^–1, which is appreciably lower than the 64 mV dec^–1 for pure RuO₂. The performed X-ray photoelectron spectroscopy (XPS) indicated that the key factor of OER activity for codoped catalysts with different dopant ratio is the oxygen vacancy.