Modulating the microenvironment of catalytic interface with functional groups for efficient photocatalytic degradation of persistent organic pollutants

The solar-driven photocatalytic degradation of persistent organic pollutants is considered as a promising water treatment approach. Nevertheless, the activity of photocatalytic degradation of pollutants is still limited by the rapid carrier recombination and sluggish oxygen mass transfer. Herein, we designed different functional groups modified WO3/R-MOF (MOF: MIL-125-Ti, R = NH2, C5H11, C5F11) heterojunction to overcome the aforementioned limitations. Among them, WO3/C5F11-MOF exhibited an excellent degradation efficiency of 91.6 % for 4-chlorophenol pollutants, which was seven and two times higher than that of WO3/NH2-MOF and WO3/C5H11-MOF, respectively. The WO3/C5H11-MOF and WO3/C5F11-MOF exhibited hydrophobic and formed microscopic triphase interface, which increased oxygen transfer. Furthermore, strong electron-withdrawing property of fluorine in the C5F11- ligand generated electron-deficient regions, increasing the transfer rate of photo-generated electrons and prolonging the relaxation time of electrons. Thus, hydrophobic WO3/C5F11-MOF not only regulates the catalytic interface microenvironment, but also effectively inhibits the recombination of photo-generated carrier. This study provides an efficient strategy to achieve excellent photocatalytic activity via interfacial engineering.