Improving photocatalytic selective coupling amine and alcohol over single-unit-cell Pd/BiVO4 nanosheets by surface synergistic effect

The single-unit-cell Pd/BiVO4 nanosheets are successfully prepared as the photocatalysts for the selective oxidative coupling of benzylamine (BZ) and benzyl alcohol (BA) to N-benzylidenebenzylamine (BZA) under visible light irradiation with an air atmosphere. Pd0.5/BVO-NS shows a high conversion (95.7%) of benzylamine and selectivity (98.9%) of N-benzylidenebenzylamine. The results of XPS and EPR suggest that abundant oxygen vacancies and low-coordinated metal atoms are exposed on the surface of BVO-NS. The result of in situ FT-IR reveals that BA molecules could be activated on BVO-NS surface via a-C-O...M (Bi and V) coordination, leading to the activation of alpha-carbon, thus enhancing the conversion of BA. The photogenerated electrons would be transferred to Pd nanoparticles via the Schottky junction for improving the separation of photogenerated electrons-holes, thereby accelerating the generation of O-2(-). Finally, a possible mechanism is proposed for un-derstanding the photocatalytic selective oxidative coupling of BZ and BA to BZA over the Pd0.5/BVO-NS. The synergism of each active sites on Pd0.5/BVO-NS achieves high photocatalytic efficiency. This work may offer an effective strategy to design photocatalysts for organic synthesis.