FT-IR study of CO adsorption on Pt/CeO2:: characterisation and structural rearrangement of small Pt particles
FT-IR study of CO adsorption on Pt/CeO2:: characterisation and structural rearrangement of small Pt particles
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DOI：
10.1039/b414159h
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发表时间：
2005-01-01
影响因子：
3.3
通讯作者：
Blanchard, G
中科院分区：
文献类型：
--
作者：
Bazin, P;Saur, O;Blanchard, G
CO 吸附后，对 Pt/CeO2 样品（Pt 负载量 = 0.5%）进行红外光谱分析，该样品在氧气和真空下处理或用 H-2 还原，然后在不同温度下抽真空。样品含有高度分散的 Pt。注意还原样品上 1937 cm(-1) 处存在不寻常的 nu((CO)) 谱带。当载体完全被 CO（液氮温度下的 CO 吸附）或甲醇完全覆盖时，不会观察到这样的带，因此可以将其分配给与配位极低的 Pt 和载体（例如，CO）结合的 CO 桥接物质。 g。到非常小的 Pt 颗粒外围的位置。在 423 K 下还原样品，然后将抽空温度提高到 423 至 673 K 后进行的实验表明，由于二氧化铈表面的 O2 迁移率，后者的增加会引起 Pt 颗粒的烧结。
CO adsorption has been followed by IR spectroscopy on a Pt/CeO2 sample (Pt loading = 0.5%) treated under oxygen and vacuum or reduced by H-2 and then evacuated at various temperatures. The sample contains highly dispersed Pt. Attention is paid to the presence of an unusual nu((CO)) band at 1937 cm(-1) on the reduced sample. Such a band is in particular not observed when the support is fully covered by CO ( CO adsorption at liquid nitrogen temperature) or by methanol, allowing one to assign it to CO bridged species bound to both Pt very lowly coordinated and to the support, e. g. to sites at the periphery of very small Pt particules. Experiments performed after sample reduction at 423 K followed by increasing evacuation temperature between 423 and 673 K showed that the increase of the latter provokes a sintering of the Pt particles, due to ceria surface O2- mobility.