Synergy of monoatomic copper and oxygen vacancy formed in-situ on ultrathin TiO2(B) nanosheet for efficient photocatalytic dehalogenative C−C coupling synthesis of bibenzyl

Abstract Photocatalytic C − C coupling reaction plays an important role in the synthesis of organics that are widely used as fine chemicals, medicine and pesticides. However, the development of high-performance, low-cost photocatalysts to drive the C − C coupling reaction under mild conditions remains a severe challenge. Herein, we present a green photocatalytic method for the selective coupling synthesis of bibenzyl over an ultrathin TiO 2 (B) nanosheet photocatalyst with single-atom Cu anchored and rich in oxygen vacancy (V O ), which were generated in-situ in the reaction system. The method requires no tedious pre-functionalization steps, which allows the use of cheap copper compounds as starting materials. The experimental results show that the introduction of single-atom Cu sites on the ultrathin TiO 2 (B) nanosheet can improve the charge transfer and separation efficiency, and the presence of surface V O not only improves the light absorption capacity but also favors the adsorption and activation of reactant benzyl bromide. More importantly, the synergy of single-atom Cu sites and surface oxygen vacancy of TiO 2 (B) endows the high efficiency in the C − C coupling synthesis of bibenzyl. This work provides a novel insight into the photocatalytic C − C coupling reaction through the collaborative strategy of single-atom Cu species and oxygen vacancy on ultrathin nanosheet photocatalysts.