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

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) in spinel NiCoO. DEI between octahedrally coordinated Ni and Co resulted in the generation of superior OER active centers Co and Ni. The multiple synergistic effects empower the electrocatalyst with exceptional OER activity, with an overpotential of 270 ± 3 mV at 10 mA/cm and a Tafel slope of 39 mV/dec, both of which are among the best values for NiCoO-based nanostructures, and even better than those for IrO and RuO.