Piezotronic Effect and Oxygen Vacancies Boosted Photocatalysis C-N Coupling of Benzylamine

Abstract Photocatalytic selective oxidation of benzylamine into high-value-added organic intermediates holds great promise. Herein, to achieve the goal of efficient separation of photo-generated electrons/holes and regulation of abundant active sites, we systematically investigated the synergistic impact of piezotronic effect and oxygen vacancies on selectively aerobic oxidation of benzylamine into N-benzylidenebenzylamine with Bi4NbO8Br single-crystalline nanosheets (BNO). We found that piezotronic effect and oxygen vacancies could collaboratively enhance the separation of photogenerated electrons and holes. Furthermore, theoretical calculations and experimental results demonstrated that oxygen vacancies can also optimize the adsorption and activation of O2 and benzylamine molecules to favor the efficient conversion of which. As a result, the conversion rates of benzylamine increased by about 2.1 times owing to the presence of piezotronic effect and oxygen vacancies. The present work opens an avenue for enhancing photocatalytic activity in selective oxidation of organic pollutant into value-added products, and also shed light on an understanding for the design of a highly efficient multi-field catalytic system in the future.