Lattice strain induced rapid structural reconstruction of NiCo hydroxide for efficient water oxidation

Abstract

In the realm of catalysis, the efficiency of nickel-cobalt (NiCo) based catalysts is hampered by the sluggish kinetics of electrochemical reconstruction. The research herein proposes an innovative strategy centered on the induction of lattice strain to surmount this challenge. We successfully engineer lattice strain and distortion within nickel-cobalt hydroxide by the strategic incorporation of iridium. The X-ray absorption spectroscopy, charge density of elements simulation, ultraviolet photoelectron spectra combined with in-situ Raman results demonstrate that the electronic coupling between iridium and nickel-cobalt is enhanced by lattice strain, which narrows the band gap, and then boosts the electrochemical reconstruction of NiCo hydroxide. Furthermore, the in-situ EIS, methanol oxidation reaction, and DFT calculations collectively indicate that lattice strain can expedite the kinetic adsorption and desorption of intermediates during the OER process. The reconstructed voltage and overpotential are reduced by 50 mV and 77 mV after introducing lattice distortion, and a high stability for more than 500 h, respectively. This unique insight into lattice strain modification provides a way to optimize catalytic functions.