Core-shell Heterostructure by Coupling Layered ReS2 with Co9S8 Nanocubes for Boosted Oxygen Evolution Reaction

The controllable morphology and composition of catalysts are crucial to improving the electrocatalytic activity of oxygen evolution reaction(OER).Herein,we construct a bimetallic heterostructure by sulfi-dation and hydrothermal methods,and the layered ReS2 is vertically aligned on Prussian blue-derived hollow Co9S8 nanocubes(Co9S8@ReS2).The core-shell structure of Co9S8@ReS2 can effectively prevent the restacking of layered ReS2,expose the abundant surface area and improve the utilization of electro-catalytic sites,resulting in fast electrolyte diffusion and charge transfer during OER.Due to the synergistic effect of the core-shell morphology and the formed bimetallic heterostructure,Co9S8@ReS2 exhibits ex-cellent catalytic OER performance.At 10mA/cm2,only 288 mV of overpotential is required with the Tafel slope of 73.3mV/dec for Co9S8@ReS2,which are both lower than that of Co9S8 and ReS2.Meanwhile,Co9S8@ReS2 exhibits high catalytic stability and low charge transfer resistance and the boosted active sites are confirmed by density functional theory.This work provides a rational design of the OER cata-lysts by constructing the bimetallic heterostructure.