Structural and synergistic effects of three-dimensionally ordered macroporous Ce0.8Zr0.2O2-supported Pt nanoparticles on the catalytic performance for soot combustion

Three-dimensionally ordered macroporous (3DOM) Ce0.8Zr0.2O2-supported Pt catalysts were firstly synthesized. All the materials possess well-defined 3DOM nanostructure and highly dispersed Pt nanoparticles on the inner walls of uniform macropores. 3DOM structure improves the contact efficiency between catalyst and soot, and the metal (Pt) support (Ce) synergistic effect increases the amount of active oxygen species. 3DOM Pt-n/Ce0.8Zr0.2O2 catalysts exhibited high catalytic activity and thermal stability for soot combustion. The structural and synergistic effects of 3DOM Pt-n/Ce0.8Zr0.2O2 catalysts are favorable for weakening the NOx constrain on the catalytic activity, e.g., the Delta T-50 of 3DOM Pt-4/Ce0.8Zr0.2O2 catalyst is only 60 degrees C, while that of Pt-4/Ce0.8Zr0.2O2-particles catalyst is 105 degrees C. The reaction pathways for catalyzing soot combustion can be divided into two parts: one is that active oxygen species directly oxidize soot particles; the other one is that NO2 acts as an intermediate to catalyze soot oxidation. (C) 2012 Elsevier B.V. All rights reserved.