Interface Engineering of RuO/Ni-CoO Heterostructures for enhanced acidic oxygen evolution reaction.

RuO has been recognized as a standard electrocatalyst for acidic oxygen evolution reaction (OER). Nonetheless, its high cost and limited durability are still ongoing challenges. Herein, a RuO/Ni-CoO heterostructure confining a heterointerface (between RuO and Ni-doped CoO) is constructed to realize enhanced OER performance. Specifically, RuO/Ni-CoO containing a low Ru content (2.7 ± 0.3 wt%) achieves an overpotential of 186 mV at a current density of 10 mA cm with a long-run stability (≥1300 h). Also, it exhibits a mass activity of 1202.29 mA mg at an overpotential of 250 mV, exceeding commercial RuO. The results disclose an optimum electron transfer at the heterointerface, wherein Ni doping improves the adsorption energy of oxygen-containing intermediates, thereby facilitating OER. This study presents an effective approach for designing highly active and stable OER electrocatalysts.