Adjusting electronic structure coupling of Fe–Ni2P (NiFeP-MOF) multilevel structure for ultra-activity and durable catalytic water oxidation

Abstract

Efficient electrocatalyst for alkaline oxygen evolution reaction is the critical core to the wide application of metal-air energy storage and water electrolysis hydrogen energy. Therefore, appropriate design of highly active and stable non-noble metal oxygen evolution electrocatalyst with good electronic structure and multilevel structure is both a goal and a challenge. Here, we report a Fe–Ni2P electrocatalyst (NiFeP-MOF) with multilevel structure, which was obtained by anion exchange on the basis of Fe–Ni(OH)2 (NiFe-MOF) grown on nickel foam in situ by solvothermal method. As expected, Fe substitution regulates the Ni oxidation state in the NiFeP-MOF and realizes electronic structure coupling, showing a highly active and stable oxygen evolution reaction (OER) in alkaline electrolyte solution. Specifically, the NiFeP-MOF demonstrates an ultralow overpotentials (232 mV, 10 mA cm−2; 267 mV 100 mA cm−2), respectively, an extremely small Tafel slope (34 mV dec−1). Separately, the electrocatalyst shows an excellent cycle stability at 10 mA cm−2 for 12 h (43,200 s). More importantly, this work come up with an available policy for the preparation of excellent alkaline hydrolysis electrolysis catalysts and air cathodes with excellent performance.