CdS/Metallic Mo Hybrid Photocatalysts with Highly Active Interfacial Mo-O-S Active Sites for Efficient Photocatalytic Hydrogen Evolution under Visible Light

Engineering an intimate interface with abundant active sites between a semiconductor and a cocatalyst is highly attractive in facilitating the charge separation and thus photocatalytic H-2 evolution performance of the resultant hybrid photocatalyst. Herein, we demonstrate that hybridizing CdS with metallic Mo nanoparticles leads to CdS/Mo photocatalysts with abundant interfacial Mo-O-S active sites resulting from the in situ reaction of surface S on CdS with native MoOx on Mo nanoparticles. The CdS/Mo hybrids exhibit a 23 times higher H-2 evolution rate (30.1 mmol h(-1) g(-1)) than pristine CdS under visible light irradiation (>= 420 nm), and the highest apparent quantum efficiency (AQE) obtained at 420 nm is as high as 43.2%. Interfacial Mo-O-S species are revealed to play an important role in promoting the charge separation on CdS and also serve as active sites for the H-2 evolution reaction. In parallel, comparative experiments indicate that the hybrid photocatalyst of metallic Mo with surface S-free TiO2 or g-C3N4 hardly exhibits enhanced H-2 evolution activities, further highlighting the important cocatalytic role of the in situ generated interfacial Mo-O-S active sites in photocatalytic H-2 evolution on CdS/Mo photocatalysts. This work emphasizes the potential of interfacial engineering in designing highly efficient photocatalysts for solar energy conversion.