In situ alkaline etching of MIL-100(Fe) to NiFe-layered double hydroxide nanosheets for electrocatalytic oxygen evolution.

Abstract

The development of efficient and durable non-noble metal electrocatalysts toward the oxygen evolution reaction (OER) is critical for the high-efficiency storage of renewable energy. Herein, a facile and controllable sacrificial template strategy is reported. Using MIL-100(Fe) as the sacrificial template under alkaline conditions, a series of NiFe-LDH electrocatalysts are fabricated by regulating the feeding amount of the nickel source, to explore the influence of Ni/Fe molar ratio on the OER electrocatalytic performance. Systematic characterization studies and electrochemical tests reveal that the optimized NiFe-LDH delivers an overpotential of 242.2 mV at 10 mA cm-2 together with a Tafel slope of 36.67 mV dec-1, surpassing commercial IrO2 and exhibiting remarkable long-term stability. Such outstanding electrocatalytic performance originates from the synergistic electronic interaction between Ni and Fe sites, which optimizes the adsorption energy of reaction intermediates and accelerates the reaction kinetics. This work not only offers a high-performance OER electrocatalyst, but also provides a versatile sacrificial template strategy for constructing advanced multimetallic electrocatalysts.