Pauling-Type Multi-Oxygen Adsorption of Amorphous MoSx Cocatalysts for Boosting Photocatalytic H2O2 Production.

The loading of cocatalysts and the modulation of their electronic properties play a crucial role in boosting photocatalytic H2O2 production. However, cocatalyst surfaces often feature multi-oxygen adsorption configurations, and how such adsorption states influence charge migration and interfacial reactions remains largely unexplored. Herein, we constructed an amorphous MoSx cocatalyst with multiple active sites on CdS photocatalysts (a-MoSx/CdS), and systematically investigated the effects of multi-oxygen adsorption on ultrafast interfacial charge transfer and interfacial reaction kinetics. Experimental results demonstrate that the optimized a-MoSx/CdS exhibits an excellent H2O2 yield of 2.94 mmol g-1 h-1, which is 2.04 and 1.6 times higher than that of pristine CdS and crystalline c-MoS2/CdS, respectively. Combined evidence from electron paramagnetic resonance (EPR), in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS), and O2 temperature-programmed desorption (O2-TPD) confirms that the abundant Mo active sites on the amorphous MoSx surface induce the formation of a Pauling-type multi-oxygen adsorption configuration. Furthermore, femtosecond transient absorption spectroscopy (fs-TAS) confirms that this multi-oxygen adsorption mechanism effectively facilitates the ultrafast interfacial migration of photogenerated electrons, substantially accelerating the interfacial reaction process. This study elucidates the intrinsic mechanism of multi-site adsorption in photocatalysis and opens up a new avenue for constructing high-performance photocatalytic systems.