Confined-space strategy for anchoring catalytic nanoparticles on Si-OH by ball milling for enhanced O3/PMS oxidation of ciprofloxacin

Design and preparation of effective catalysts for advanced oxidation processes (AOPs) remain challenging, especially concerning the creation of strong interactions between catalytic sites and the support, which is essential for effective charge transfer and generation of reactive oxygen species (ROSs). In the present work, a pore-confinement approach based on a green ball milling method is proposed to anchor Co-Ce nanoparticles on a mesoporous silica support, and its chemical features and advantages are addressed. Remarkably, such a catalyst exhibited high activity due to the enhanced interface-mediated electron transfer, giving superior total organic carbon (TOC) removal (>70%) of ciprofloxacin (CIP) after only 10 min of treatment with O3/peroxymonosulfate (O3/PMS), which was much higher than for a catalyst synthesized by a traditional non-confined space process in previous reported literature. This confinement effect could stretch Co-Co bonds in a tetrahedral coordination and promote the growth of highly dispersed nanosized particles due to the Si-OH anchoring according to the results of X-ray absorption fine structure (XAFS). Furthermore, theoretical analysis revealed that Co3O4 {111} as main active sites significantly raised the adsorption of PMS, CIP and O3 than other phase, thereby favoring catalyst-reactant interaction and boosting electron transfer in this system.

Automated summary

This study successfully anchored Co-Ce nanoparticles on a mesoporous silica support through pore-confinement approach, enhancing the catalytic activity and achieving over 70% total organic carbon removal of ciprofloxacin, surpassing traditional synthesis methods. XAFS results suggested that the confinement effect stretched Co-Co bonds and promoted highly dispersed nanoparticle growth.