Mechanism insight into twin-dependent photocatalysis in near-infrared light-responsive Cu2O nanocrystals with rich oxygen vacancies

Simultaneous integration of rich oxygen vacancies (OVs) and twin crystals in a photocatalyst can not only significantly enhance the near-infrared (NIR) light response but also greatly improve the photocharge separation and transfer efficiency owing to the induced high electrical conductivity and strong built-in electric field. However, thus far, there has been a lack of a model catalyst containing both twin crystals and OVs. Herein, we develop a simple wet chemical strategy for synthesizing of unprecedented NIR light-responsive OVs-rich Cu₂O black nanoparticles with high-density of twin crystals (denoted as black twinned Cu₂O). As expected, the black twinned Cu₂O exhibits higher visible-NIR and NIR light-driven photodegradation of tetracycline (TC) solution than the counterparts. Significantly, the mechanism insight into twin-dependent photocatalysis in NIR light-responsive Cu₂O black nanocrystals with rich OVs is uncovered in depth by density functional theory (DFT) calculations and a series of experimental evidence. Expectantly, this work would be beneficial for the scientific researchers currently focusing on the NIR light-responsive photocatalysis and twin engineering of photocatalysts.