Mesoporous SiO2-Encapsulated Nano-Co3O4 Catalyst for Efficient CO Oxidation

Abstract

To meet the increasing demand for efficient and durable catalysts for exhaust aftertreatment system, a mesoporous SiO2-encapsulated nano-Co3O4 catalyst was synthesized, which possesses a unique pitaya-like structure with high CO oxidation activity and thermal stability. Though the silica matrix is inert, the encapsulated Co3O4 exhibits increased oxygen storage capacity, enhanced CO2 desorption behavior and high lattice oxygen reactivity. Additionally, the SiO2-encapsulated Co3O4 catalyst can be effectively regenerated rather than the supported Co3O4/SiO2 and pure Co3O4. The kinetic results demonstrate that the L−H mechanism is followed over the pure Co3O4 nanoparticles catalyst, while the CO oxidation over the silica-supported Co3O4 catalysts obey to both L−H and MVK mechanism. The encapsulation structure of the as-prepared catalyst can effectively restrain the aggregation of Co3O4 during high temperature operations and improves the utilization efficiency of cobalt resources, as well, which would be suitable for practical applications.