Charging d-Orbital Electron of ReS_(2+x) Cocatalyst Enables Splendid Alkaline Photocatalytic H_2 Evolution

摘要

Rhenium disulfide (ReS_2) holds expansive perspective in photocatalyticwater-splitting field, but its H_2-production rate is severely impeded by thestrong hydroxyl (OH_(ad)) adsorption on catalytic Re atoms. Herein, aningenious strategy about charging d-orbital electrons of ReS_(2+x) cocatalyst byintegrating metallic Au is explicitly clarified to effectively accelerate OH_(ad)desorption for promoting alkaline photocatalytic H_2-evolution activity. To thisend, core-shell Au@ReS_(2+x) nanostructures as H_2-production cocatalysts areskillfully fabricated onto TiO_2 by a directional assembly pathway. Experimentaland theoretical data validate an free-electron transfer from metallic Au core toS-rich ReS_(2+x) shell, thus essentially charging electrons to the d-orbital of Reatoms to construct active Re~((4- )+) sites. The charged d-orbital electron state ofRe~((4- )+) atoms raises antibonding occupancy of the Re~((4- )+)–OH_(ad) bonds,thereby accelerating OH_(ad) desorption and endowing core-shell Au@ReS_(2+x)cocatalysts an efficient H_2 production from alkaline water splitting. Moreover,the core-shell Au@ReS_(2+x) cocatalysts can effectively capture photogeneratedelectrons from TiO_2 as unveiled by operando Kelvin probe force microscopy.Consequently, the optimized TiO_2/Au@ReS_(2+x) photocatalyst achieves anexceptional H_2-production rate of 6013.45 μmol h~(?1) g~(?1) with releasing visualH_2 bubbles in alkaline media. This research furnishes original insights forcharging orbital electrons to optimize the adsorption strength betweenintermediates and catalytic atoms.