Ce-UiO-66-NH2-MOF-derived doped cerium oxide as a highly efficient sonophoto-Fenton catalyst for amoxicillin degradation

The ubiquitous presence of β-lactam antibiotics like amoxicillin (AMX) in aquatic environments is increasingly becoming a threat to ecosystems and human health through its promotion of antimicrobial resistance. Herein, we report a Ce-UNH-MOF-derived cerium oxide (CNC) catalyst designed through MOF-to-oxide conversion with a high degree of control to sonophoto-Fenton degrade amoxicillin in a highly efficient manner. Thermal conversion of Ce-UNH produces a porous, oxygen-vacancy-enriched cerium oxide with an abundance of Ce 3+ /Ce 4+ redox centers with high electron conductivity. With the combined action of visible light, ultrasonic irradiation and H 2 O 2 , the derived oxide is able to degrade AMX by 90% in 60 min with a high apparent rate constant of 0.038 min -1 , which is significantly higher than pristine MOF (79%) and other processes like photocatalysis (71%) or sonocatalysis (56%). Mechanistic studies convey that ultrasonic cavitation boosts mass transfer and Ce 3+ regeneration whereas photoexcitation supports the growth of exciton separation and ROS production. Radical scavenging test and electron spin resonance (ESR) analyses identify hydroxyl radicals ( • OH) as the dominant active species, with auxiliary contributions from superoxide (•O 2 ⁻). The catalyst demonstrates excellent stability and reusability after five cycles. This work establishes MOF-to-Oxide engineering as an effective strategy to design redox-active cerium catalysts for advanced sonophoto-Fenton oxidation and antibiotic remediation.