Exploration and Application of the Self-Optimization Phenomenon of a Trimetal-Based MOF Electrocatalyst in the Oxygen Evolution Reaction

Abstract

Metal–organic frameworks (MOFs) have emerged as a promising class of catalysts due to their large specific surface area, high porosity, and dispersed metal sites. However, the inherent low electrical conductivity of organic ligands limits their application as electrocatalysts. Herein, we constructed a trimetal FeCoNi MOF/NF catalyst for oxygen evolution reaction (OER) on nickel foam substrates by electrodeposition and hydrothermal methods. The FeCoNi MOF/NF catalyst shows a unique self-optimization phenomenon, which originates from the increase in the pore structure on the topography, the increase in the valence state of Co and Ni ions, and the formation of crystalline/amorphous interfaces. The self-optimizing stabilized FeCoNi MOF/NF has excellent electrocatalytic performance, which achieves a low overpotential of 267 mV at the current density of 10 mA cm–2 in 1 M KOH with a small Tafel slope of 37.6 mV dec–1. The self-optimization transformation process proposed in this work provides a new insight for the understanding and application of the active center of MOFs during the OER catalytic process.