Engineered Co2AlO4/CoAl2O4@Al2O3 monolithic catalysts for peroxymonosulfate activation: Co3+/Co2+ and ODefect/OLattice ratios dependence and mechanism

Immobilizing metal-organic frameworks in macro-supports to form three-dimensional catalysts holds a great promise in environmental remediation, however quantitative structure/property-catalytic activity relationship remains unknown currently. In this work, we constructed Co2AlO4/CoAl2O4@Al2O3 monoliths derived from [email protected]γ-Al2O3 pellets and systematically investigated their surface chemistry-activity relationships in peroxymonosulfate (PMS) activation for organic degradation. The activities of Co2AlO4/CoAl2O4@Al2O3 catalysts were selectively correlated with their ratios of Co3+/Co2+ and ODefect/OLattice. The optimized Co2AlO4/CoAl2O4@Al2O3 demonstrated an excellent catalytic efficacy toward PMS activation for metronidazole removal in a wide pH range (3.29–10.26) and OH was the dominant oxidant for metronidazole oxidation. The catalyst also exhibited desirable performance for eliminating other emerging contaminants and enduring catalytic activity and stability in PMS activation without regeneration. This study provides new prospects in rational design of robust, cost-effective and self-cleaning/repairing three-dimensional Co-based macroscale-catalysts with an outstanding and lasting catalytic activity for water purification.