Interfacial electronic modulation by Fe2O3/NiFe-LDHs heterostructures for efficient oxygen evolution at high current density

Abstract

Designing and fabricating well-defined heterointerface catalysts with high electrocatalytic performance for oxygen evolution reaction (OER) at the industrial grade current density still remains a huge challenge. Here the flower-like nanosheets with rich Fe₂O₃/NiFe-layered double hydroxides (LDHs) heterointerfaces were fabricated, and they exhibit superior catalytic activity with a very low overpotential of 220 mV for OER at the industrial grade current density of 500 mA cm^− 2 and fast reaction kinetics with a small Tafel slope of 32 mV dec⁻¹. Based on the analyses of operando Raman spectra, DFT theoretical calculations and electrochemical characterizations, the superior electrocatalytic performance of catalysts for OER at the industrial grade current density can be attributed to Fe₂O₃/NiFe-LDHs heterointerfaces that can obviously promote interfacial electron transfer from Ni²⁺ to Fe³⁺ and optimize d-orbit electronic configuration with e_g occupancy of Ni close to the unity, resulting in moderate adsorption/desorption energies of oxygenated intermediates, and thus facilitating remarkably electrocatalytic performance and superior intrinsic kinetics for OER in alkaline media.