Three-dimensional porous CuO-modified CeO2-Al2O3 catalysts with chlorine resistance for simultaneous catalytic oxidation of chlorobenzene and mercury: Cu-Ce interaction and structure

Chlorine poisoning effects are still challenging to develop efficient catalysts for applications in chlorobenzene (CB) and mercury (Hg⁰) oxidation. Herein, three-dimensional porous CuO-modified CeO₂-Al₂O₃ catalysts with macroporous framework and mesoporous walls prepared via a dual template method were employed to study simultaneous oxidation of CB and Hg⁰. CuO-modified CeO₂-Al₂O₃ catalysts with three-dimensional porous structure exhibited outstanding activity and stability for simultaneous catalytic oxidation of CB and Hg⁰. The results demonstrated that the addition of CuO into CeO₂-Al₂O₃ can simultaneously enhance the acid sites and redox properties through the electronic inductive effect between CuO and CeO₂ (Cu²⁺+Ce³⁺↔Cu⁺+Ce⁴⁺). Importantly, the synergistic effect between Cu and Ce species can induce abundant oxygen vacancies formation, produce more reactive oxygen species and facilitate oxygen migration, which is beneficial for the deep oxidation of chlorinated intermediates. Moreover, macroporous framework and mesoporous nanostructure dramatically improved the specific surface area for enhancing the contact efficiency between reactants and active sites, leading to a remarkable decrease of byproducts deposition. CB and Hg⁰ had function of mutual promotion in this reaction system. In tune with the experimental results, the possible mechanistic pathways for simultaneous catalytic oxidation of CB and Hg⁰ were proposed.