Bidentate binuclear coordination configuration for peroxymonosulfate catalytic regulation through incorporation of CuFeOx to iron-based metal organic frameworks

The scheme of coordination bridge modification provides a new vision for regulating the catalytic pathway, but how to change the surface coordination of peroxymonosulfate (PMS), thereby affecting the catalytic mechanism of PMS, is still an unknown field. In this, we found that MIL-101(Fe) is expected to control the surface catalytic pathway via the bidentate binuclear coordination configuration, thereby realizing the rapid oxidative detoxification of toxic organic pollutants and CO2 conversion. Introducing Cu on the surface of MIL-101(Fe) to change the surface chemical environment (MIL-101 (Fe)/CuFeOx) can shift the catalytic pathway, thereby promoting a 14.5-fold improvement in Bisphenol A (BPA) oxidation kinetics (from 0.00697 min(-1) to 0.101 min(-1)). Characterization, experiments, and density functional theory (DFT) results show that Cu in the vicinity of Fe can tune the electronic structure and properties of Fe-O-Cu, thereby enhancing the electron transfer rate at the active center, facilitating electronic transitions and PMS adsorption. More importantly, shifting the binding configuration of PMS from monodentate mononuclear coordination on a single Fe center to bidentate binuclear coordination on Fe/Cu centers, shorter distance coordination structures and O-O pulling of PMS. The effect promoted PMS cleavage to generate more ROS and changed the catalytic pathway from the radical pathway to the O-1(2) and high-valent metal species pathway. The free radical/non-radical pathway co-mediated by O-1(2), high-valent metal species, center dot OH and SO4 center dot- can effectively reduce the biotoxicity of toxic organic pollutants, and can utilize alkali environment captures CO2 as a stable carbonate for environmental use. This study provides a strategy for manipulating the catalytic pathway through coordination configuration and a feasible idea for CO2 conversion in wastewater treatment.

Automated summary

The coordination bridge modification scheme provides a new perspective for regulating the catalytic pathway. MIL-101(Fe)/CuFeOx is found to control the surface catalytic pathway and enhance the oxidation of toxic organic pollutants and CO2 conversion. The introduction of Cu changes the surface chemical environment and promotes the reaction kinetics. The coordination configuration of Cu and Fe tunes the electronic structure, facilitating electron transfer and PMS adsorption. The change in PMS binding configuration shifts the catalytic pathway, generating more ROS and reducing the biotoxicity.