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

Abstract

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.