Boosting the Catalytic Performance of CeO2 in Toluene Combustion via the Ce-Ce Homogeneous Interface.

Abstract

Catalytic combustion is an advanced technology to eliminate industrial volatile organic compounds such as toluene. In order to replace the expensive noble metal catalysts and avoid the aggregation phenomenon occurring in traditional heterogeneous interfaces, designing homogeneous interfaces can become an emerging methodology to enhance the catalytic combustion performance of metal oxide catalysts. A mesocrystalline CeO2 catalyst with abundant Ce-Ce homogeneous interfaces is synthesized via a self-flaming method which exhibits boosted catalytic performance for toluene combustion compared with traditional CeO2, leading to a ∼40 °C lower T90. The abundant Ce-Ce homogeneous interfaces formed by both highly ordered stacking and small grain size endow the CeO2 mesocrystal with superior redox property and oxygen storage capacity via forming various oxygen vacancies. Surface and bulk oxygen vacancies generate and activate crucial oxygen species, while interfacial oxygen vacancies further promote the reaction behavior of oxygen species (i.e., activation, regeneration, and migration), causing the splitting of redox property toward lower temperature. These properties facilitate aromatic ring decomposition, the important rate-determining step, thus contributing to toluene catalytic degradation to CO2. This work may shed insights into the catalytic effects of homogeneous interfaces in pollutant removal and provide a strategy of interfacial defect engineering for catalyst development.