Shaping a soot combustion Ce0.5Pr0.5Ox catalyst

Abstract

A Ce0.5Pr0.5Ox soot combustion catalyst has been shaped combining this material prepared in two different structures (nanoparticles and MS-macroporous) in a single active phase. Nanoparticles, prepared by reversed microemulsion method, provide high activity to the hybrid material, and the MS structure, obtained by a hard template synthesis method, provides high thermal stability and improved soot-catalyst contact. Ce0.5Pr0.5Ox nanoparticles present high surface area (148 m2/g; 5 nm) and improved redox properties with regard to other Ce0.5Pr0.5Ox structures, and the macropores size of MS Ce0.5Pr0.5Ox are large enough (around 100 nm) to properly disperse Ce0.5Pr0.5Ox nanoparticles inside and also to host soot particles, creating a high reactive catalyst environment. As a result, the as prepared Ce0.5Pr0.5Ox hybrid catalyst, mixed in loose-contact mode with soot, decreased soot combustion by ca. 100 °C with regard to the uncatalyzed reaction, and thermal aging at 800 °C only decreased this difference to ca. 75 °C. The as-prepared counterpart hybrid catalyst obtained dispersing pure ceria nanoparticles on pure ceria MS support was also active for soot combustion, but the activity was almost lost completely upon thermal aging due to ceria sintering.