Oxidation of Nitric Oxide on Gas-Phase Cerium Oxide Clusters via Reactant Adsorption and Product Desorption Processes
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- 作者：Toshiaki Nagata ; Ken Miyajima ; Fumitaka Mafun茅
- 刊名：Journal of Physical Chemistry A
- 出版年：2015
- 出版时间：October 15, 2015
- 年：2015
- 卷：119
- 期：41
- 页码：10255-10263
- 全文大小：474K
- ISSN：1520-5215
文摘
The reactivity of cerium oxide cluster cations, CenO2n+x+ (n = 2鈥?, x = 鈭? to +2), with NO was investigated using gas-phase temperature-programmed desorption (TPD) combined with mass spectrometry. Target clusters were prepared in the gas phase via the laser ablation of a cerium oxide rod in the presence of oxygen, which was diluted using helium as a carrier gas. NO adsorbed onto stoichiometric and oxygen-rich clusters of CenO2n+x+ (x = 0鈥?), forming CenO2n+x(NO)+ (x = 0鈥?) species. Gas-phase TPD was measured for the NO-adsorbed clusters, revealing that CenO2n(NO)+ released NO2 at 600鈥?00 K, forming CenO2n鈥?+. Therefore, the overall reaction was the oxidation of NO by the CenO2n+ clusters, which was explained in terms of a Langmuir鈥揌inshelwood type reaction. An activation barrier existed between the initial complex (CenO2n(NO)+) and the final oxidation products (CenO2n鈥?+ + NO2). To determine the nature of the intermediates and the activation barrier, TPD was also performed on CenO2n鈥?(NO2)+, which had been prepared through the adsorption of NO2 on CenO2n鈥?+ for comparison. The activation barrier was associated with the release of NO2 from the intermediate complex (CenO2n鈥?+鈥擭O2 鈫?CenO2n鈥?+ + NO2) rather than the structural rearrangement that formed NO2 in the other intermediate complex (CenO2n+鈥擭O 鈫?CenO2n鈥?+鈥擭O2).