Engineering of Bi–S3 and sulfur-vacancy dual sites for efficient photocatalytic N-alkylation of amines

Abstract

Here, we report a ZnIn₂S₄-based photocatalyst that features dual active sites consisting of interfacial Bi–S₃ bonds and sulfur-vacancies in ZnIn₂S₄ nanosheets (denoted as Bi–S₃/S-V_s), which catalyze cascading oxidation and reduction to achieve alcohol-based N-alkylation of amines. Remarkably, the Bi–S₃/S-V_s photocatalyst provides an excellent yield (94.5%) of N-benzylaniline in the model alkylation reaction of aniline and benzyl alcohol, which is greater than that of comparative samples. Charge carrier dynamics and theoretical evidence reveal that the enhanced photocatalytic performance of the Bi–S₃/S-V_s photocatalyst originates from the unique coordination structure and electronic properties of Bi–S₃ and sulfur vacancy (V_s) dual sites, which can act as the reduction and oxidation sites, respectively, to accomplish the cascade reaction for N-alkylation of amines by alcohols in one photocatalytic system. This study provides a new insight into designing high-efficiency photocatalysts with atomic precision.