Stabilization of flavin mononucleotide by capturing its "tail" with porous organic polymers for long-term photocatalytic degradation of micropollutants.

Flavin mononucleotide (FMN) produces photo-induced reactive oxygen species (ROS), making it a bio-based and sustainable photosensitizer for micropollutant degradation. However, the rapid self-degradation of FMN under light poses challenges in practical applications. We propose for the first time to use porous organic polymer (POP) structures as particles and in situ grown on nanofibrous membranes to capture the ribityl side chain ("tail") of FMN by electrostatic-driven guest-host interaction. By restraining the free bending mode of FMN in POP, its self-degradation is highly inhibited, showing a prolonged half-life (102.7 and 79.7 times to that in solution and in β-cyclodextrin, respectively) without any impact on the ROS production even after 16 h of UVA irradiation. As a proof-of-concept, the photocatalytic degradation efficiency of FMN-POP complexes can be achieved at 58-93% against micropollutants under UVA. The stabilization of FMN by the "tail" capture in the POP allows its photocatalytic degradation function to be continuously online.