Charging d‐Orbital Electron of ReS2+x Cocatalyst Enables Splendid Alkaline Photocatalytic H2 Evolution

Abstract

AbstractRhenium disulfide (ReS2) holds expansive perspective in photocatalytic water‐splitting field, but its H2‐production rate is severely impeded by the strong hydroxyl (OHad) adsorption on catalytic Re atoms. Herein, an ingenious strategy about charging d‐orbital electrons of ReS2+x cocatalyst by integrating metallic Au is explicitly clarified to effectively accelerate OHad desorption for promoting alkaline photocatalytic H2‐evolution activity. To this end, core‐shell Au@ReS2+x nanostructures as H2‐production cocatalysts are skillfully fabricated onto TiO2 by a directional assembly pathway. Experimental and theoretical data validate an free‐electron transfer from metallic Au core to S‐rich ReS2+x shell, thus essentially charging electrons to the d‐orbital of Re atoms to construct active Re(4‐δ)+ sites. The charged d‐orbital electron state of Re(4‐δ)+ atoms raises antibonding occupancy of the Re(4‐δ)+OHad bonds, thereby accelerating OHad desorption and endowing core‐shell Au@ReS2+x cocatalysts an efficient H2 production from alkaline water splitting. Moreover, the core‐shell Au@ReS2+x cocatalysts can effectively capture photogenerated electrons from TiO2 as unveiled by operando Kelvin probe force microscopy. Consequently, the optimized TiO2/Au@ReS2+x photocatalyst achieves an exceptional H2‐production rate of 6013.45 µmol h−1 g−1 with releasing visual H2 bubbles in alkaline media. This research furnishes original insights for charging orbital electrons to optimize the adsorption strength between intermediates and catalytic atoms.