Ni-Induced C-Al₂O₃-Framework (_NiCAF) Supported Core-Multishell Catalysts for Efficient Catalytic Ozonation: A Structure-to-Performance Study

During catalytic ozonation, Al₂O₃-supported catalysts usually have stable structures but relatively low surface activity, while carbon-supported catalysts are opposite. To encourage their synergisms, we designed a Ni-induced C-Al₂O₃-framework (_NiCAF) and reinforced it with a Cu-Co bimetal to create an efficient catalyst (CuCo/_NiCAF) with a core-multishell structure. The partial graphitization of carbon adjacent to Ni crystals formed a strong out-shell on the catalyst surface. The rate constant for total organic carbon removal of CuCo/_NiCAF (0.172 ± 0.018 min^-1) was 67% and 310% higher than that of Al₂O₃-supported catalysts and Al₂O₃ alone, respectively. The metals on CuCo/_NiCAF contributed to surface-mediated reactions during catalytic ozonation, while the embedded carbon enhanced reactions within the solid-liquid boundary layer and in the bulk solution. Moreover, carbon embedment provided a 76% increase in ·OH-production efficiency and an 86% increase in organic-adsorption capacity compared to Al₂O₃-supported catalysts. During the long-term treatment of coal-gasification wastewater (∼5 m³ day^-1), the pilot-scale demonstration of CuCo/_NiCAF-catalyzed ozonation revealed a 120% increase in ozone-utilization efficiency (ΔCOD/ΔO₃ = 2.12) compared to that of pure ozonation (0.96). These findings highlight catalysts supported on _NiCAF as a facile and efficient approach to achieve both high catalytic activity and excellent structural stability, demonstrating that they are highly viable for practical applications.