Pauling-Type Multi-Oxygen Adsorption of Amorphous MoS_x 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 MoS_x cocatalyst with multiple active sites on CdS photocatalysts (a-MoS_x/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-MoS_x/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 MoS_x 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.