ISSN:
1013-9826
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
An innovative Pd-perovskite “Intelligent Catalyst”, which exhibits a greatly improveddurability owing to the self-regeneration function of Pd nanoparticles, has been developed. ThePd-perovskite catalyst was prepared by the alkoxide method, and X-ray absorption fine structure(XAFS) measurements were carried out in SPring-8 using the 8-GeV synchrotron radiation. Pdoccupied the B-site (6-fold coordination) of the perovskite lattice in the oxidative atmosphere, andsegregated out to form metallic nanoparticles in the reductive atmosphere. The catalyst retained apredominantly perovskite structure throughout a redox cycle of the exhaust-gas, while the localstructure around Pd could be changed in a completely reversible manner. The agglomeration andgrowth of the metal particles is suppressed as a result of the Pd movement between inside and outsidethe perovskite lattice. This function enables an automotive catalyst to regenerate itself into an activestate in fluctuation typically encountered in the exhaust gas from the gasoline engine. And it isrevealed, by in-situ and ex-situ XAFS analyses, that the self-regenerative function of Pd occurred in awide temperature range from very low to high one. The intelligent catalyst is one solution forprecious metals supply and demand problem, and is expected to become the global standard of thecatalyst technology
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/01/51/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.317-318.827.pdf
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