NiCo-layered double hydroxides /Co9S8 with heterogeneous structure as ultra-high performance electrocatalyst for oxygen evolution reaction

Abstract

Heterogeneous interface engineering is an ideal method for designing low-cost and efficient electrocatalysts for oxygen evolution reaction (OER). NiCo-layered double hydroxide (LDH)/Co9S8 with heterogeneous structure was prepared by a two-step hydrothermal method and employed for OER. The layered structure with a spherical base exhibited the lower overpotential (151 mV) and Tafel slope (100 mV dec−1) at a current density of 10 mA cm−2, which surpass commercially available IrO2 and most reported non-precious metal electrocatalysts. The synergistic effect at the interface can increase the conductivity of the material, induce electron migration between NiCo-LDH and Co9S8, and decrease the energy barrier of the OER intermediate, thereby increasing the electrocatalytic activity. At the same time, heterostructures with rough surfaces and ultra-hydrophilic properties can provide the desired stability, promote ion penetration and the release of bubbles, improve the accessibility of the active site, and thus enhance the catalytic performance of OER. This work provides a feasible way to develop high performance OER electrocatalysts.