Dynamic shape, structure and oxidation changes for Pd metal fine particles during CO/NO catalytic reaction

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

In recent years, there have been many reports which investigate the dynamic shape and structure changes of metal fine particles. Now metal fine particle system is becoming a original physical research field. In this study, dynamic changes of Pd metal fine particles during CO/NO catalytic reaction were observed by in situ and real-time-resolved method. Dispersive X-ray absorption spectroscopy system is suitable for above purpose. The Pd particles on LaFeO were used for the observation of 0.1 Hz rate at 300-500 C in order to reveal the local atomic and electronic structures. Under the CO atmosphere, it was revealed that the interatomic distance is slightly elongated and the mean coordination number is reduced. While, a stable surface oxide layer was recognized under the NO flow, which is critically different with the case of the Pd particles on alumina.