LaFePdO3 perovskite automotive catalyst having a self-regenerative function
LaFePdO3 perovskite automotive catalyst having a self-regenerative function
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DOI：
10.1016/j.jallcom.2004.12.138
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发表时间：
2006-02
影响因子：
6.2
通讯作者：
Hirohisa Tanaka;Isao Tan;M. Uenishi;Taniguchi Masashi;M. Kimura;Y. Nishihata;J. Mizuki
中科院分区：
文献类型：
--
作者：
Hirohisa Tanaka;Isao Tan;M. Uenishi;Taniguchi Masashi;M. Kimura;Y. Nishihata;J. Mizuki
车用汽油机在接近化学计量空燃比的情况下运行，以同时转换污染物排放，并通过调整空燃比来伴随尾气成分的氧化还原(还原和氧化)波动。开发了一种新型的钙钛矿型LaFe0.95Pd0.05O3型催化剂，称为“智能催化剂”，在汽车尾气固有的波动中具有贵金属的新的自再生功能。采用醇盐法制备了LaFe0.95Pd0.05O3型钙钛矿催化剂，La位于A位。Pd在氧化气氛中位于钙钛矿晶格的B位，在还原气氛中偏析形成金属微粒。在整个废气氧化还原循环中，催化剂保持了以钙钛矿为主的结构，而Pd周围的局部结构可以完全可逆地改变。即使在恶劣的环境下，由于钙钛矿晶格内外的运动，Pd颗粒的团聚和生长也受到了抑制。结果表明，在LaFe0.95Pd0.05O_3催化剂中，Pd在200℃的低温下仍具有自再生功能。由于保持了较高的催化活性，大大降低了钯的负载量。智能催化剂有望成为稀土的一种新应用，该技术也有望成为全球催化剂设计的标准。
An automotive gasoline engine is operated close to the stoichiometric air-to-fuel ratio to convert the pollutant emissions simultaneously, accompanying with redox (reduction and oxidation) fluctuations in exhaust-gas composition through adjusting the air-to-fuel ratio. An innovative LaFe0.95Pd0.05O3perovskite catalyst, named ‘the intelligent catalyst’, has been developed, and which has a new self-regenerative function of the precious metal in the inherent fluctuations of automotive exhaust-gas. The LaFe0.95Pd0.05O3perovskite catalyst, La located at the A-site, was prepared by the alkoxide method. Pd located at the B-site of the perovskite lattice in the oxidative atmosphere, and segregated out to form small metallic particles in the reductive atmosphere. The catalyst retained a predominantly perovskite structure throughout a redox cycle of the exhaust-gas, while the local structure around Pd could be changed in a completely reversible manner. The agglomeration and growth of Pd particles is suppressed, even under the severe environment, as a result of the movement between inside and outside the perovskite lattice. It is revealed that the self-regenerative function of Pd occurs even at 200°C, unexpectedly low temperature, in the LaFe0.95Pd0.05O3catalyst. Since the high catalytic activity is maintained, the great reduction of Pd loading has been achieved. The intelligent catalyst is expected as a new application of the rare earth, and then the technology is expected in the same way in the global standard of the catalyst designing.