Electrochemical Construction of a NiFe Multiphase Heterointerface for Oxygen Evolution Reaction

Rational design of transition metal-based electrocatalysts is crucial to stimulate the slow kinetics of those oxygen evolution reactions (OER) toward hydrogen energy utilization. Herein, we prepare a self-supported electrocatalyst Ni3Fe@NiFe-LDH/NF with a NiFe multiphase heterointerface by one-step electrodeposition. In particular, Cl– is utilized to expand the pore structure of the nickel foam (NF) substrate during electrodeposition and effectively increase the number of oxygen vacancies on electrocatalyst surfaces during electrooxidation. Relevant density functional theory (DFT) calculations show that active charge transfer at the heterointerface modulates the d-band center of active elements (i.e., Ni, Fe) and attenuates the d–p orbital hybrid strength of the oxygenated intermediates, thus optimizing the adsorption free energy of the reaction path. Due to the effect of Cl– ions and NiFe multiphase heterointerfaces, Ni3Fe@NiFe-LDH/NF exhibits outstanding alkaline electrocatalytic OER activities. The overpotential of Ni3Fe@NiFe-LDH/NF is as low as 145/195 mV at 10/100 mA cm–2 in 1 M KOH, while the Tafel slope is only 36.8 mV dec–1. In addition, Ni3Fe@NiFe-LDH/NF provides a current density of 100 mA cm–2 for more than 30 h without obvious decay, exhibiting good electrochemical stability. This work shows promising engineering of transition metal-based electrocatalysts toward high-performance OER kinetics in hydrogen energy utilization.