Dynamic structural change of Pd particles on LaFeO under redox atmosphere and CO/NO catalytic reaction studied by dispersive XAFS

Matsumura, Daiju   ; Okajima, Yuka; Nishihata, Yasuo; Mizuki, Junichiro; Taniguchi, Masashi*; Uenishi, Mari*; Tanaka, Hirohisa*

Pd/LaFeO is known to keep the metal particle size small even after the long time redox processes because Pd atoms make complex oxide with LaFeO perovskite-type crystal under the oxidative atmosphere. We observed the local structure of Pd atoms by dispersive optics from the viewpoint of dynamical structure change of Pd during metal-oxide change and CO-NO catalytic reaction. It was recognized that, under the reductive atmosphere, Pd atoms show similar speed of movement from oxide to metal state both on LaFeO and AlO. However, under the oxidative atmosphere, Pd atoms on LaFeO show faster movement from metal to oxide state with single reaction step than those on AlO with two-step oxidation. In addition, many differences in structure and shape between Pd particles on LaFeO and AlO are observed.