Abstract
Inspired by the concept of frustrated Lewis pairs (FLPs) from homogeneous catalysis, an organic supramolecular bridged metal-organic frameworks (MOFs) heterojunction, i.e., a perylene-3,4,9,10-tetracarboxylic diimide@MIL-125(Ti)-NH2 (denoted PDI@MTi) composite is successfully fabricated via a two-step synthesis method. Experimental characterisations and theoretical calculations reveal that in the obtained 'TiO_(5-x)-ligand-PDI" FLPs, the unsaturated Ti-Oclusters function as a Lewis acid to accept photogenerated electrons, and the PDI sites act as a Lewis base to capture photogenerated holes. With the unique structure characteristics, the PDI@MTi shows excellent photocatalytic activity toward the disinfection of Staphylococcus aureus and Cr(VI) reduction, with 1.0- and 10.3-fold enhancements, respectively, compared with unadorned MTi. The synergic effects of the micro polarisation field, multiple active sites, and a C-N bonded interface contributed to photoactivity enhancement. This work demonstrates the potential of using MTi as a platform for constructing FLPs-containing heterogeneous photocatalysts and provides new strategies to control carrier separation.
NSTL