In situ XPS study of the adsorption and reactions of NO and O2 on gold nanoparticles deposited on TiO2 and SiO2
In situ XPS study of the adsorption and reactions of NO and O2 on gold nanoparticles deposited on TiO2 and SiO2
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DOI：
10.1016/j.jcat.2011.06.022
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发表时间：
2011-10-27
影响因子：
7.3
通讯作者：
Salmeron, Miguel
中科院分区：
文献类型：
--
作者：
Herranz, Tirma;Deng, Xingyi;Salmeron, Miguel
用常压光电子能谱（APPES）研究了一氧化氮（NO）和分子氧（O-2）在由不同粒径（2-5 nm）的单分散金纳米颗粒和氧化物载体（包括多晶SiO2和TiO 2薄膜）组成的金基模型催化剂上的吸附. APPES是一种原位技术，可以通过XPS监测催化剂表面发生的化学变化，并识别反应条件下的吸附物质。在我们的实验中，没有观察到任何变化的Au/SiO2样品在暴露于0.5托的NO，而吸附的NO和几个含N的物种检测Au/TiO 2模型催化剂在相同的条件下。此外，在TiO 2中的Ti 3 p和O 1 s峰相对于Au 4f峰观察到位移。当使用O-2时，在Au/TiO 2样品上观察到类似的行为，尽管程度较小。在这两种情况下，Ti 3 p和O 1 s峰的位移可以归因于由气体的化学吸附引起的TiO 2衬底上的能带弯曲效应。(C)2011 Elsevier Inc. All rights reserved.
Ambient pressure photoelectron spectroscopy (APPES) has been used to study the adsorption of nitric oxide (NO) and molecular oxygen (O-2) over gold-based model catalysts consisting of mono-dispersed gold nanoparticles with different diameters (2-5 nm) and oxide supports (including polycrystalline silica and titania thin films). APPES is an in situ technique that makes possible to monitor via XPS chemical changes occurring on the catalyst surface and to identify adsorbed species under reaction conditions. In our experiments, no changes were observed on the Au/SiO2 samples during exposure to 0.5 Torr of NO, while adsorbed NO and several N-containing species were detected on Au/TiO2 model catalysts under the same conditions. In addition, shifts in the Ti3p and O 1s peaks in TiO2 were observed relative to the Au 4f peak. Similar behavior, although to a lesser extent, was observed on Au/TiO2 samples when O-2 was used. In both cases, the shifts of the Ti3p and O 1s peaks could be attributed to band bending effects on the TiO2 substrate caused by chemisorption of the gases. (C) 2011 Elsevier Inc. All rights reserved.