Low-Temperature Dissociation of CO2 on a Ni/CeO2(111)/Ru(0001) Model Catalyst

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• 作者：Dandan Kong ; Junfa Zhu ; Karl-Heinz Ernst
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：March 24, 2016
• 年：2016
• 卷：120
• 期：11
• 页码：5980-5987
• 全文大小：470K
• ISSN：1932-7455

文摘

The adsorption of CO₂ on CeO_2-x(111) and Ni/CeO_2-x(111)/Ru(0001) surfaces has been studied with reflection absorption infrared spectroscopy (RAIRS) and X-ray photoelectron spectroscopy (XPS). On the maximal-oxidized CeO₂(111) surface physisorbed linear CO₂ and a CO₂^– species are identified at 97 K. The reduced CeO_2-x(111) surface exhibits higher reactivity toward adsorbed CO₂, which leads to higher coverages of CO₂^– and promotes CO₂ dissociating into CO and an active oxygen species at higher temperature, reoxidizing the reduced CeO_2-x(111) films. Deposition of Ni on the maximal-oxidized CeO₂ thin films leads to slight reduction of ceria films. Adsorption of CO₂ on Ni/CeO_2-x(111) films causes dissociation at 97 K and leads to Ni-CO adsorbates plus partial oxidation of Ni nanoparticles. This process is inhibited when Ni nanoparticles on CeO₂ are fully oxidized. In contrast to the results reported for CO₂ adsorption on Ni single-crystals, where the dissociation temperature was found to be higher than 240 K, the much lower dissociation temperature (∼97 K) for CO₂ on Ni nanoparticles supported on CeO₂(111) suggests that the Ni/CeO₂ catalyst exhibits high activity toward CO₂ activation.