Construction of a Nanorod Structure-Confined Pt@CeO 2 Catalyst by an In-Situ Encapsulation Strategy for Low-Temperature Catalytic Oxidation of Toluene.

In this work, Pt@CeO 2 catalysts with a nanorod structure (Pt@CeO 2 -R) and a bunch structure (Pt@CeO 2 -B) were synthesized through an in-situ encapsulation strategy of Pt species in Ce-MOFs, respectively. It was discovered that the Pt@CeO 2 -R catalyst possessed the best catalytic performance for toluene catalytic combustion, and this result was mainly caused by the confinement of Pt nanoparticles in Ce-MOFs, which was related to the chemical state of Pt species, redox ability, and the amount of active oxygen species. The Pt@CeO 2 -R catalyst contained more Ce 3+ species, rich Pt 4+ species, and abundant active oxygen species due to the existence of the confined effect, which was conducive to promote catalytic oxidation of toluene. In addition, the Pt@CeO 2 -R catalyst also exhibited more redox ability, which may speed up the catalytic reaction rates. On the contrary, the Pt/CeO 2 -R catalyst was synthesized through a simple impregnation method and exhibited the poor activity for toluene catalytic combustion due to poor Pt 4+ species and active oxygen species. Therefore, this work provides a feasible experimental basis for the study of different morphologies and encapsulated metal nanoparticles.