Optimization of Co₃O₄ surface sites for photo-ozone catalytic mineralization of dichloromethane

Obtaining high removal rate of chlorinated volatile organic compounds (CVOCs) and CO₂ selectivity with a low ratio of O₃/CVOC and energy consumption is challenging. Dodecylamine was used in this study to create active sites on Co₃O₄ for photo-ozone catalytic mineralization of dichloromethane (DCM). Amine-Co₃O₄-450 is a dodecylamine-modified sample with high density of Co³⁺, Co²⁺, and hydroxyl due to its nanosheet structure and exposed (112) facets. The optimized surface significantly enhanced the cleavage of the C-Cl bond at low temperatures. Photocatalysis primarily participated in the oxidation of intermediates following DCM dichlorination and significantly improved CO₂ selectivity. The respective DCM removal rate and mineralization efficiency of Amine-Co₃O₄-450 with an O₃/DCM molar ratio of 1.27 and one-sun irradiation were 14.9 and 15.0 times higher than the sum of those in the presence of light irradiation or O₃ alone. This finding indicated that a strong synergistic effect exists between O₃ and light.