Dual modulation of lattice strain and charge polarization induced by Co(OH)2/Ni(OH)2 interfaces for efficient oxygen evolution catalysis

Abstract

Two-dimensional transition metal hydroxides are greatly limited in the application of the electrocatalytic oxygen evolution reaction (OER) due to its large and inert basal planes. Herein, we report a one-step in situ etching hydrothermal method to construct Co(OH)₂ and Ni(OH)₂ heterostructure nanomaterials, successfully activating the basal plane of Co(OH)₂. The abundant lattice strains that appear at heterogeneous interfaces cause a downshift of the d-band center of Co in Co(OH)₂ and promote the desorption of oxygen during the OER process, which accelerates reaction kinetics of the OER and improves catalytic activity effectively. Furthermore, the electron interaction at the Co(OH)₂/Ni(OH)₂ interfaces leads to charge polarization, which will regulate the adsorption and dissociation of H₂O molecules and enhances mass and electron transfer. Owing to the above advantages of Co(OH)₂/Ni(OH)₂ interfaces, the as-prepared composite catalysts show an excellent OER catalytic performance with a low overpotential of only about 270 mV at 20 mA cm⁻², maintaining long-term catalytic stability for more than 24 h at 20 mA cm⁻².