Enhancing Ce-Co interfacial effects via special petal-pollen morphology construction to achieve efficient toluene removal

Abstract

Interfacial effects provide an effective means to construct multi-metal interactions and design efficient catalysts for VOCs purification, while morphology construction remains a common tactic to optimize the efficiency of these catalysts. In the present work, the Co-Ce bimetal interface was effectively constructed by morphological regulation, and the coupling of the interfacial effect modulation and the special morphological structure was realized, resulting in superior catalyst performance. Among the series catalysts, CeCoOx-H demonstrated the optimized activity with 90 % toluene conversion at 250 °C while maintaining good results in a 50 h stability test. And the systematic characterization revealed that the structural changes and interfacial effects induced by morphological modulation would increase the structural defects, improving surface reactive oxygen and oxygen vacancy content, oxygen storage capacity, oxygen motivity and low-temperature reductivity, which account for promising catalytic performance of CeCoOx-H. Furthermore, in-situ DRIFTS revealed the following decomposition routes for toluene on the CeCoOx-H catalyst surface: toluene → benzyl alcohol → benzaldehyde → benzoate → phenol → maleate → acetate → formate → carbon dioxide. In particular, the decomposition of benzaldehyde and benzoate may be the key steps in toluene catalytic oxidation. Also, the characterization unveiled that the rich adsorption sites brought by the interfacial construction are not negligible in boosting the catalytic performance.