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High Resolution Image Download MS PowerPoint Slide Photocatalytic water splitting represents a promising approach for solar energy utilization, but its performance is primarily constrained by the sluggish water oxidation reaction, where the hole transfer at the solid/liquid interface plays a significant role. Despite extensive experimental and theoretical efforts, the hole trapping mechanism of TiO 2, a widely used photocatalyst, in the aqueous environment is still controversial. Here, using first-principles molecular dynamic simulations, we establish the hole trapping sites and the hole transfer mechanisms at the anatase TiO 2 (001)/water interface. Both molecular and dissociative H 2 O adsorptions are considered. We demonstrate that the holes at the adsorbed H 2 O and HO – species are unstable and migrate spontaneously to TiO 2, whereas the deprotonated O 2– ions can be oxidized and retain the holes forming stable structures. Further, bulk water facilitates hole localization at the TiO 2 /water interface, and in turn, the trapped holes regulate the interfacial water configuration. These findings provide fundamental insights into the photocatalytic performance and interfacial charge separation.
Han et al. (Sun,) studied this question.