Precise and controllable synthesis of NiFe2O4 spinel oxides with porous sheet-like morphology for OER

Developing cost-efficient, eco-friendly and high-performance electrocatalysts for oxygen evolution reaction (OER) is important to practical implementation of energy technologies like water electrolysis and rechargeable metal−air batteries. Spinel-type complex oxides exhibit significant potential as electrocatalysts for OER, attributed to their natural abundance, structural diversity, compositional flexibility, and exceptional stability. Therefore, we develop a Hofmann-type CP-derived approach to synthesize porous NiFe 2 O 4 nanosheets (NSs) involving the precipitation of precursors and thermal decomposition under precise temperature. The fabricated NiFe 2 O 4 NSs have well-preserved the original sheet-like morphology, and have also created plentiful pores and oxygen vacancies. Electrochemical results indicate that the obtained NiFe 2 O 4 NSs exhibit superior electrocatalytic performance with smaller overpotential of 320 mV at 10 mA cm −2 , Tafel slope of 51.5 mV dec −1 , and remarkable long-term stability in alkaline electrolytes compared to commercial RuO 2 . The present synthetic strategy provides a feasible pathway for preparing other diverse metal oxides with well-defined porous nanostructures for energy applications.