Thermally stable sandwich-type catalysts of Pt nanoparticles encapsulated in CeO2 nanorod/CeO2 nanoparticle core/shell supports for methane oxidation at high temperatures

Abstract

The thermal stability of nanocatalysts is of great importance to develop high performing catalysts in terms of high activity and robust catalytic stability, especially for high-temperature catalysis. Herein, we report a sandwich-type Pt nanocatalyst encapsulated in ceria-based core/shell supports (CNR@Pt@CNP), which consists of CeO₂ nanorods as core, CeO₂ nanoparticles as shell and Pt nanoparticles (PtNPs) embedded between the CeO₂ nanorods and CeO₂ nanoparticles. The catalysts exhibited remarkable thermal stability at high temperature by effectively preventing PtNPs from thermal sintering. Methane combustion was carried out on the CNR@Pt@CNP catalysts at 400–700 °C to evaluate their catalytic activity and stability. By comparing to the same amount of PtNPs supported on CeO₂ nanorods (CNR@Pt), CNR@Pt@CNP delivered higher catalytic activity at high temperatures (>500 °C). The methane conversion catalyzed by CNR@Pt@CNP slightly decreased from 82.3% to 80.0% after 12 hours at 650 °C. The improved performance of CNR@Pt@CNP originated from the CeO₂ nanoparticles as stabilizer, which can prevent the thermal sintering of PtNPs, strengthen the thermal stability of the catalyst and enhance the metal-support interaction.