Boosted Oxygen Evolution Reactivity by Igniting Double Exchange Interaction in Spinel Oxides

摘要

A double-exchange interaction (DEI) was demonstrated to boost the oxygen evolution reaction (OER) in spinel oxides. DEI was ignited by synergistic actions of constructing nanoheterojunctions and creating oxygen vacancy (V_O) in spinel NiCo_2O_4. DEI between octahedrally coordinated Ni and Co resulted in the generation of superior OER active centers Co~((3-δ)+) and Ni~(3+). The multiple synergistic effects empower the electrocatalyst with exceptional OER activity, with an overpotential of 270 ± 3 mV at 10 mA/cm~2 and a Tafel slope of 39 mV/dec, both of which are among the best values for NiCo_2O_4-based nanostructures, and even better than those for IrO_2 and RuO_2.