Open AccessStructural analysis of La/Al 2 O 3 catalysts by La K ‐edge XAFS
Author(s) -
Yamamoto Takashi,
Tanaka Tsunehiro,
Matsuyama Takahiro,
Funabiki Takuzo,
Yoshida Satohiro
Publication year - 2001
Publication title -
journal of synchrotron radiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 99
ISSN - 1600-5775
DOI - 10.1107/s0909049500017106
Subject(s) - x ray absorption fine structure , catalysis , aluminate , materials science , oxide , xanes , perovskite (structure) , structural change , crystallography , chemistry , metallurgy , spectroscopy , physics , organic chemistry , quantum mechanics , cement , economics , macroeconomics
Structural analysis of La/Al 2 O 3 catalyst materials was carried out by means of XRD and La K‐edge XAFS. Influences of loading amounts and treatment temperature on the local structure around La were investigated. La atoms are supported on γ‐Al 2 O 3 in a highly dispersed form when a loading amount is less than 0.2 mmol g(Al 2 O 3 )‐1, and structural transformation of the La species does not take place in the temperature ranges of 873‐1273 K. La species of highly loaded catalysts start to change their structure from oxide‐like form to the aluminate at 1073 K. Formation of LaAlO 3 perovskite on the catalyst surface requires a concentration of La atoms above 0.5 mmol g(Al 2 O 3 ) −1 (7.5 wt% as La 2 O 3 ).