Citrate-regulated synthesis of hydrotalcite-like compounds as peroxymonosulfate activator - Investigation of oxygen vacancies and degradation pathways by combining DFT

This work investigated the triggering mechanism of peroxymonosulfate (PMS) activated by an oxygen vacancy (Ov)-rich cobalt (Co)-based hydrotalcite-like compound (CA-LDH). CA-LDH was synthesized by a urea -hydrothermal process with ammonium citrate (CA) as the reducing agent. The PMS activation mechanism was investigated by combining batch experiments, characterization techniques, and DFT calculations. Over 98 % of CIP (20 mg/L) was degraded by the CA-LDH/PMS system within 60 min, which remained efficient in the presence of common interfering substances or over a wide pH range. DFT showed that CA was beneficial for introducing the electron transfer intermediate, namely, O-v, on CA-LDH, thereby allowing for the unique electron transfer performance of CA-LDH. Specifically, electron transfer from Co-O-v to PMS triggered the radical pathway, while electron transfer from PMS to Co-O-v triggered the nonradical pathway. Overall, this study provides a reference for the rational catalyst synthesis and the investigation of the triggering mechanism of PMS activation.

Automated summary

This study investigated the triggering mechanism of peroxymonosulfate activated by an oxygen vacancy-rich cobalt-based hydrotalcite-like compound, revealing its high efficiency in degrading CIP and providing insights into electron transfer pathways. The findings offer valuable references for rational catalyst synthesis and the investigation of PMS activation mechanisms.