Synergy of Facet and Defect on Carrier Dynamics of Photocatalyst Particles

Cu₂O semiconductors are highly regarded in photocatalysis for their outstanding photogenerated carrier dynamics. However, the mechanisms underlying carrier separation and recombination in Cu₂O remain elusive, largely due to the intricate interplay between defects and facet engineering. Herein, we elucidate the critical synergy between internal defects and facets in Cu₂O for carrier dynamics. Specifically, split Cu vacancy and H interstitial defects preferentially capture holes and electrons, respectively, leading to effective separation of photogenerated carriers in the different Cu₂O facets. Moreover, H interstitials can also convert split Cu vacancies into H-filled Cu vacancies, eliminating midgap states and extending the photogenerated carrier lifetime of Cu₂O. The efficient separation and extended lifetime of carrier enhances the photocatalytic efficiency of Cu₂O. Our findings reveal the defect-dependent mechanism for photogenerated carrier dynamics in photocatalysts with different facets, offering valuable insights for facet regulation in high-performance photocatalysis.