Construction of Active Orbital via Single-Atom Cobalt Anchoring on the Surface of 1T-MoS₂ Basal Plane toward Efficient Hydrogen Evolution

Abstract

Endowing the basal plane of metallic MoS2 with highly active catalytic sites is one strategy to promote its hydrogen evolution reaction (HER) catalytic performance. Since there is unsuitable orbital orientation at the Fermi energy level, the activity of HER for the perfect basal plane in metallic 1T phase MoS2 (1T-MoS2) is insufficient. Herein, we resolved this issue through a single-atom cobalt-introduced active orbital. The prepared cobalt (Co)-doped 1T-MoS2 displays a significantly enhanced HER activity. The overpotential at 10 mA cm–2 is 84 mV. The Tafel slope is 47 mV dec–1. The results of experiment and theory reveal that the doped Co atoms anchor preferentially on the Mo top sites, acting as active sites and possessing a Gibbs free energy near zero for hydrogen adsorption. Theoretical calculation further reveals that the high activity of Co anchoring on the surface is attributed to the introduction of a dz2 orbital perpendicular to the basal plane around the Fermi level, enabling energetically and sterically favorable hydrogen adsorption/desorption.