Interface Engineering of RuO₂/Ni-Co₃O₄ Heterostructures for enhanced acidic oxygen evolution reaction

RuO₂ 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 RuO₂/Ni-Co₃O₄ heterostructure confining a heterointerface (between RuO₂ and Ni-doped Co₃O₄) is constructed to realize enhanced OER performance. Specifically, RuO₂/Ni-Co₃O₄ containing a low Ru content (2.7 ± 0.3 wt%) achieves an overpotential of 186 mV at a current density of 10 mA cm^-2 with a long-run stability (≥1300 h). Also, it exhibits a mass activity of 1202.29 mA mg_Ru^-1 at an overpotential of 250 mV, exceeding commercial RuO₂. 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.