Free‐Electron Inversive Modulation to Charge Antibonding Orbital of ReS2 Cocatalyst for Efficient Photocatalytic Hydrogen Generation

Abstract

AbstractThe free electron transfer between cocatalyst and photocatalyst has a great effect on the bonding strength between the active site and adsorbed hydrogen atom (Hads), but there is still a lack of effective means to purposely manipulate the electron transfer in a beneficial direction of H adsorption/desorption activity. Herein, when ReSx cocatalyst is loaded on TiO2 surface, a spontaneous free‐electron transfer from ReSx to TiO2 happens due to the smaller work function of ReSx, causing an over‐strong S‐Hads bond. To prevent the over‐strong S‐Hads bonds of ReSx in the ReSx/TiO2 , a free‐electron reversal transfer strategy is developed to weaken the strong S‐Hads bonds via increasing the work function of ReSx by incorporating O to produce ReOSx cocatalyst. Research results attest that a larger work function of ReOSx than that of TiO2 can induce reversal transfer of electrons from TiO2 to ReOSx to produce electron‐rich S(2+δ)−, causing the increased antibonding‐orbital occupancy of S‐Hads in ReOSx/TiO2 . Accordingly, the stability of adsorbed H on S sites is availably decreased, thus weakening the S‐Hads of ReOSx. In this case, an electron‐rich S(2+δ)−‐mediated “capture‐hybridization‐conversion” mechanism is raised . Benefiting from such property, the resultant ReOSx/TiO2 photocatalyst exhibits a superior H2‐evolution rate of 7168 µmol h−1 g−1 .