Boosting the electrochemical performance of mesoporous NiCo 2 O 4 oxygen evolution catalysts by facile surface modifying

To effectively develop enhanced oxygen evolution reaction (OER) catalysts, we propose a surface anion and cation co-modification strategy toward mesoporous NiCo2O4. After a simple ethanol-assisted grinding and subsequent annealing process, the modified NiCo2O4 catalysts (NiCo2O4-FeF3-A) exhibit a superior OER catalytic activity and stability compared with other controlled samples. The overpotential value to drive the standard OER current density of 10 mA cm−2 in 1 M KOH electrolyte is only 260 mV, significantly decreasing by as large as 110 mV relative to the pristine NiCo2O4. In addition, negligible degeneration is observed during accelerated durability tests (ADTs) for 5000 cycles, confirming the strong interaction between oxide substrates and modified ions. The enhancement of electro-catalytic activity can be attributed to the effective and accelerated charge-transfer process induced by surface electronic state reconstruction.