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 (<i>χ</i>Te-NiCo LDH) was grown on a three-dimensional porous nickel foam (NF) using a facile solvothermal method with <i>χ</i> = 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 <i>χ</i>Te-NiCo (<i>χ</i> = 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 (<i>χ</i>) 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 (<i>χ</i>) introduced into the NiCo LDH is discussed with respect to the OER performance.