Pt-Co nanoparticles supported on hollow multi-shelled CeO2 as a catalyst for highly efficient toluene oxidation: Morphology control and the role of bimetal synergism

A series of hollow multi-shelled CeO2(HoMS-CeO2) support materials with tunable shell numbers were fabricated and applied to the catalytic oxidation of toluene. HoMS-CeO2 possess much higher catalytic activity (T-90 = 236 degrees C) than hollow CeO2 with only a single shell (h-CeO2) (T-90 = 275 degrees C). The porous multiple-shelled structure has a higher SBET, which strongly promotes gas distribution and provides more active sites. The superiority of this kind of structure was also verified by comparing h-Co3O4 and HoMSCo3O4. Furthermore, Pt-Co bimetallic nanoparticles were loaded onto HoMS-CeO2. The synergistic effect between Pt and Co was verified by XPS and O-2-TPD, which was observed to allow electron transfer between Pt and Co and thus regulate the electronic state of the Pt. Compared with Pt alone, Pt-Co bimetallic nanoparticles could strongly promote the activation of O-2 and oxygen mobility, as revealed by a much higher O-ads content and a lower oxygen desorption temperature. Of the catalysts prepared in this study, the 1 wt% PtCo3/CeO2 catalyst was found to be the most suitable for toluene oxidation owing to its excellent activity (T-90 = 158 degrees C), long-term stability, and water resistance. Finally, in situ DRIFTS was employed to investigate mechanism during toluene oxidation and the possible reaction pathway was proposed. (C) 2021 Elsevier Inc. All rights reserved.