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Rare‐Earth‐Doped Pt/Ba/Ce 0.6 Zr 0.4 O 2 ‐Al 2 O 3 for NO x Storage and Reduction: The Effect of Rare‐Earth Doping on Efficiency and Stability
Author(s) -
Wang Xiuyun,
Chen Zhilin,
Wang Yuling,
Wang Ruihu
Publication year - 2014
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201300750
Subject(s) - raman spectroscopy , x ray photoelectron spectroscopy , analytical chemistry (journal) , materials science , doping , spectroscopy , nuclear chemistry , crystallography , chemistry , physics , nuclear magnetic resonance , optoelectronics , chromatography , optics , quantum mechanics
Rare‐earth‐doped Pt/Ba/RO‐CZA (RO=La 2 O 3 , Nd 2 O 3 and Y 2 O 3 ; CZA=Ce 0.6 Zr 0.4 O 2 ‐Al 2 O 3 ) were synthesized and characterized by XRD, N 2 physisorption, Raman spectroscopy, H 2 temperature‐programmed reduction, extended X‐ray absorption fine structure analysis, scanning transmission electron microscopy, and X‐ray photoelectron spectroscopy. The effect of the addition of rare earths on Pt/Ba/RO‐CZA was explored, and the relationship between their structures and properties was disclosed. In comparison with Pt/Ba/CZA, La and Nd addition, especially La addition, resulted in an apparent increment of oxygen vacancies and the improvement of the reductive capacity of Ce 4+ , which are favorable for NO x reduction. However, the presence of Y induced a negative effect on NO x storage and reduction (NSR). The NSR performances of Pt/Ba/RO‐CZA were initially evaluated by using NO‐to‐NO 2 conversion, NO x storage capacity, and NO x conversion. The NO x conversion in Pt/Ba/La‐CZA and Pt/Ba/Nd‐CZA at 350 °C is up to 98 and 94 %, respectively. Interestingly, the addition of rare earths contributes to the enhancement of the thermal stability, a slight decrement of NO x conversion was observed after Pt/Ba/RO‐CZA were maintained at 350 °C for 100 h, whereas an obvious loss of catalytic activity was found in Pt/Ba/CZA under the same conditions. TEM analysis showed that the presence of La inhibits the agglomeration of Pt and the sintering of particles.