Regulating CeO2 morphologies on the catalytic oxidation of toluene at lower temperature: A study of the structure-activity relationship

Developing efficient and stable non-noble metal catalysts for the catalytic oxidation of volatile organic compounds (VOCs) has always been key for controlling air pollution. For this, cerium dioxide (CeO2) is a potential material and its morphology has a significant impact on the catalyst performance. Herein, three types of CeO(2)with different morphologies were prepared using the hard template method and successfully applied to toluene oxidation. The CeO2 nanoparticles catalyst (CeO2-NP) exhibited the highest efficiency, excellent water resistance, long-term stability, and cycle regeneration. Notably, the activation and migration of lattice oxygen can be facilitated by increasing the temperature, and the oxygen vacancies on the surface of the catalyst can further promote the process. In addition, the oxidation behavior of toluene over the CeO2-NP catalyst was comprehensively understood by in situ diffuse reflectance infrared Fourier transform spectroscopy (In situ DRIFTS) combined with density functional theory (DFT). It was found that the ring-opening reaction is an essential rate-controlling step. Thus, this study provides a new strategy for exploring mono-metal catalysts with high catalytic performances for the oxidation of VOCs and other pollutants.

Automated summary

Developing efficient and stable non-noble metal catalysts for VOCs oxidation is crucial in controlling air pollution. In this study, different morphologies of CeO2 catalysts were prepared and the CeO2 nanoparticles exhibited the highest efficiency, water resistance, stability, and regeneration ability. In situ DRIFTS combined with DFT were used to understand the oxidation behavior of toluene over the CeO2 nanoparticles catalyst, and it was found that the ring-opening reaction is a rate-controlling step. This study provides a new strategy for exploring high-performance catalysts for VOCs oxidation and other pollutant treatments.