Exploring the impact of atomic lattice deformation on oxygen evolution reactions based on a sub-5 nm pure face-centred cubic high-entropy alloy electrocatalyst

Abstract

Multimetal high-entropy alloys (HEAs) have been recognized as potential catalysts that can possibly replace the conventional metal oxides and noble metals for use in energy conversion and water splitting such as oxygen evolution reactions (OERs). However, their higher catalysis is restrained by the difficulty in the synthesis of HEAs with desirable morphologies and deformed crystal lattice structures. In this work, an advanced approach was developed to fabricate the smallest possible HEA (i.e., MnFeCoNiCu) with deformed nanoparticles supported on the carbon cloth (CC) surface. The nanoparticles were characterized to be single face-centered cubic (FCC) crystals with highly deformed lattices, giving rise to various defects (such as twins, dislocations and stacking faults). The high surface tension caused by these defects leads to a substantial reduction in the overpotential down to 263 mV for the production of 10 mA cm⁻² with a very low Tafel slope of 43 mV dec⁻¹ and a rather small charge transfer resistance of 0.644 Ω in 1.0 M KOH, which is exceptionally lower than that of RuO₂ and the state-of-the-art HEAs and competitive in comparison to most metal oxides. This work proves that the lattice deformation manipulates the displacement of atoms over the nanoparticle surface that facilitates their catalytic activities that are higher than those of the state-of-the-art counterparts reported in the literature. It also provides an insight into the performance improvement of other nanostructures in energy applications.