Free-Electron Inversive Modulation to Charge Antibonding Orbital of ReS₂ Cocatalyst for Efficient Photocatalytic...

The free electron transfer between cocatalyst and photocatalyst has a great effect on the bonding strength between the active site and adsorbed hydrogen atom (H_ads), 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 ReS_x cocatalyst is loaded on TiO₂ surface, a spontaneous free-electron transfer from ReS_x to TiO₂ happens due to the smaller work function of ReS_x, causing an over-strong S-H_ads bond. To prevent the over-strong S-H_ads bonds of ReS_x in the ReS_x/TiO₂ , a free-electron reversal transfer strategy is developed to weaken the strong S-H_ads bonds via increasing the work function of ReS_x by incorporating O to produce ReOS_x cocatalyst. Research results attest that a larger work function of ReOS_x than that of TiO₂ can induce reversal transfer of electrons from TiO₂ to ReOS_x to produce electron-rich S^(2+δ)-, causing the increased antibonding-orbital occupancy of S-H_ads in ReOS_x/TiO₂ . Accordingly, the stability of adsorbed H on S sites is availably decreased, thus weakening the S-H_ads of ReOS_x. In this case, an electron-rich S^(2+δ)--mediated "capture-hybridization-conversion" mechanism is raised . Benefiting from such property, the resultant ReOS_x/TiO₂ photocatalyst exhibits a superior H₂-evolution rate of 7168 µmol h^-1 g^-1 .