PDI bridged MIL-125(Ti)-NH2 heterojunction with frustrated Lewis pairs: A promising photocatalyst for Cr(VI) reduction and antibacterial application

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 [email protected](Ti)-NH2 (denoted [email protected]) composite is successfully fabricated via a two-step synthesis method. Experimental characterisations and theoretical calculations reveal that in the obtained “TiO5−x-ligand-PDI” FLPs, the unsaturated Ti-O clusters 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 [email protected] 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.