Tellurium-Incorporated Nickel-Cobalt Layered Double Hydroxide and Its Oxygen Evolution Reaction

Transition-metal-based layered double hydroxides (LDHs) have attracted substantial attention as highly efficient oxygen evolution reaction (OER) catalysts because they are earth-abundant, low-cost, and environmentally friendly materials with favorable adsorption/desorption energies for intermittent reactants. However, the application of these LDHs as high-performance electrocatalysts is often hindered by their relatively sluggish electronic transport kinetics resulting from their intrinsically low conductivity. Here, we report the effects of incorporating a metalloid into transition metal LDHs on their electrocatalytic activity. In this study, Te-incorporated NiCo LDH (χTe-NiCo LDH) was grown on a three-dimensional porous nickel foam (NF) using a facile solvothermal method with χ = 0.2, 0.4, 0.6 and 0.8. The crystal structure and surface nanostructure were investigated by X-ray diffraction and field-emission scanning electron microscopy. A homogeneous nanosheet structure on the NF was clearly observed for the NiCo LDH and χTe-NiCo (χ = 0.2, 0.4, 0.6) LDHs. However, irregular and collapsed nanostructures were found on the surface of the NF when the Te precursor ratio (χ) exceeded 0.6. The electrocatalytic OER properties were analyzed by linear sweep voltammetry and electrochemical impedance spectroscopy. The amount of Te used in the electrocatalytic reaction was found to play a crucial role in improving the catalytic activity. The optimum Te amount (χ) introduced into the NiCo LDH is discussed with respect to the OER performance.