<i>In Situ</i> and Simultaneous Observation of Palladium Redox and Oxygen Storage/Release in Pd/Sr–Fe–O Perovskite Catalysts Using Dispersive XAFS
2013; Volume: 54; Issue: 2 Linguagem: Inglês
10.2320/matertrans.m2012297
ISSN1347-5320
AutoresMasao Kimura, Y. Niwa, Kenichi Uemura, Tatsuzo Nagai, Yasuhiro Inada, Masaharu Nomura,
Tópico(s)Electrocatalysts for Energy Conversion
ResumoWe have succeeded in in situ and simultaneously observing the redox reaction of palladium and the oxygen storage/release process in a newly developed palladium-promoted Sr–Fe–O (Pd/Sr–Fe–O) catalyst during redox-gas cycles using dispersive X-ray absorption fine structure (XAFS) analysis at 673 K with a time resolution of less than 20 ms. The Pd/Sr–Fe–O catalyst, which exhibits high performance for automotive emission control, has a unique "multi-phase-domain" structure, where a single grain is composed of nano-sized domains of three phases: SrFeO3−δ, Sr4Fe6O13−δ and SrFe12O19−δ. In situ observation has shown a strong correlation between the redox of the palladium and the oxygen storage/release in the Pd/Sr–Fe–O catalyst, and the correlation factors differ between the reduction and oxidation reactions. The oxide phases exhibit a type of "oxygen buffer" effect in the oxidation cycle and delay the formation of Pd–O, resulting in the high performance of the catalyst.
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