Boosting the photocatalytic performances of covalent organic frameworks enabled by spatial modulation of plasmonic nanocrystals

Abstract

Plasmonic Au nanocrystals (NCs) are incorporated into covalent organic frameworks (COFs) with precisely modulated distributions to improve the efficiency of electron-hole separation and optimize the charge-carrier utilization. Specifically, through balancing the rate of dynamic covalent reactions and assembly of NCs, sparsely dispersed Au NCs (AuSP/COFs) or the close packed ones (AuCP/COFs) in COFs are fabricated, in which the contributions of electron acceptors/cocatalysts on the catalytic properties of Au/COFs composites are addressed by EPR, PL, and electrochemical measurements. Au3SP/COFs shows the best photocatalytic performances in photodegradation of RhB (remove >95 % in 120 min, kw=1.8 min−1 g−1) and dehalogenation of phenacyl bromide (conversion >99 %, selectivity of acetophenone ∼92.8 %) under visible light irradiation, which are associated with accelerated electron transfer, increased available Au/COFs Schottky junctions and boosted interfacial reaction kinetics. Overall, this work contributes to the fundamental understanding of the how spatial distributions of NCs in COFs affect the photocatalytic performances.