Dynamic structural change in Pd-perovskite automotive catalyst studied by time-resolved dispersive x-ray absorption fine structure

Author:

Matsumura, Daiju  Nishihata, Yasuo  Mizuki, Jun'ichiro  Taniguchi, Masashi  Uenishi, Mari  Tanaka, Hirohisa  

Journal:

JOURNAL OF APPLIED PHYSICS

Issue Date:

2010

Abstract(summary):

Dynamic structural change in Pd-perovskite automotive catalyst, LaFe(0.9)Pd(0.1)O(3), which has a high catalytic activity during aging, was studied by in situ time-resolved dispersive x-ray absorption fine structure spectroscopy at 200-500 degrees C. An Al(2)O(3)-based conventional catalyst was also studied. In a reductive atmosphere, both catalysts showed similar temperature dependences of structural transformation from an oxide to a metal. However, different temperature dependence was observed in an oxidative atmosphere. A faster response in the structural change was observed in the Pd-perovskite catalyst than in the Pd/Al(2)O(3) catalyst. It was revealed that Pd-perovskite shows a considerably fast structural change to the oxidized state via the movement of Pd atoms into the perovskite crystal, in comparison with Pd/Al(2)O(3) showing two-step structural change for making PdO. (C) 2010 American Institute of Physics. [doi :10.1063/1.3437084]