BiVO4 quadrangular nanoprisms with highly exposed {101} facets for selective photocatalytic oxidation of benzylamine

Photocatalytic oxidation of amines to high value-added imines is crucial but challenging. The adsorption ability to reactant molecules and the charge separation ability are important factors affecting the reactivity. Different facets of monoclinic BiVO4 (m-BiVO4) have varied electronic structures, leading to differences in the adsorption ability and charge separation ability. Thus, tailoring the exposed facets is a promising strategy to optimize the reactivity. Herein, the density functional theory (DFT) calculations demonstrate that for m-BiVO4, both the benzylamine (BnNH2) adsorption ability and charge separation ability of {101} facets were stronger than those of {110} facets. These results motivate us to synthesize m-BiVO4 quadrangular nanoprisms (Q-BiVO4) with highly exposed {101} facets through a colloidal two-phase method. Q-BiVO4 exhibits highly enhanced charge separation efficiency and excellent photocatalytic performance for oxidizing BnNH2 to N-benzylidenebenzylamine (N-BB). More impressively, the efficient charge transfer between Q-BiVO4 and BnNH2 was directly confirmed via single-particle spectroscopy in situ. This work provides direct evidence to deeply understand the interaction between Q-BiVO4 and the reactant molecules and provides insights for rational design of photocatalysts with specific exposed facets for selective oxidation of amines.

Automated summary

This study investigates the effect of different crystal facets on the adsorption ability and charge separation ability of BiVO4 towards amines. Based on these findings, quadrangular nanoprisms with highly exposed specific facets of BiVO4 were successfully synthesized, and their excellent photocatalytic performance for selective oxidation of amines was demonstrated, providing a new design strategy for selective oxidation of amines using photocatalysts.