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Energy Level Shifts at the Silica/Ru(0001) Heterojunction Driven by Surface and Interface Dipoles. Top Catal 2016. [DOI: 10.1007/s11244-016-0704-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Cai JQ, Luo HJ, Tao XM, Tan MQ. Initial Subsurface Incorporation of Oxygen into Ru(0001): A Density Functional Theory Study. Chemphyschem 2015; 16:3937-48. [DOI: 10.1002/cphc.201500681] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 10/02/2015] [Indexed: 11/07/2022]
Affiliation(s)
- Jian-Qiu Cai
- Department of Physics; Zhejiang University; No. 38 Zheda Road Hangzhou 310027 China
- College of Physics and Electronic Information Engineering; Wenzhou University, Chashan Higher Education Park; Wenzhou 325035 China
| | - Hai-Jun Luo
- Department of Physics; Zhejiang University; No. 38 Zheda Road Hangzhou 310027 China
- College of Physics and Electronic Information Engineering; Wenzhou University, Chashan Higher Education Park; Wenzhou 325035 China
| | - Xiang-Ming Tao
- Department of Physics; Zhejiang University; No. 38 Zheda Road Hangzhou 310027 China
| | - Ming-Qiu Tan
- Department of Physics; Zhejiang University; No. 38 Zheda Road Hangzhou 310027 China
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Rosenthal D, Girgsdies F, Timpe O, Blume R, Weinberg G, Teschner D, Schlögl R. On the CO-Oxidation over Oxygenated Ruthenium. ACTA ACUST UNITED AC 2009. [DOI: 10.1524/zpch.2009.6032] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Abstract
The oxidation of carbon monoxide over polycrystalline ruthenium dioxide (RuO2) powder was studied in a packed-bed reactor and by bulk and surface analytical methods. Activity data were correlated with bulk phases in an in-situ X-ray diffraction (XRD) setup at atmospheric pressure. Ruthenium dioxide was pre-calcined in pure oxygen at 1073 K. At this stage RuO2 is completely inactive in the oxidation of CO. After a long induction period in the feed at 503 K RuO2 becomes active with 100% conversion, while in-situ XRD reveals no changes in the RuO2 diffraction pattern. At this stage selective roughening of apical RuO2 facets was observed by scanning electron microscopy (SEM). Seldom also single lateral facets are roughened. EDX indicated higher oxygen content in the following order: flat lateral facets > rough lateral facets > rough apical facets. Further, experiments in the packed bed reactor indicated oscillations in the CO2 formation rate. At even higher temperatures in reducing feed (533–543 K) the sample reduces to ruthenium metal according to XRD. The reduced particles exhibiting lower ignition temperature are very rough with cracks and deep star-shaped holes. An Arrhenius plot of the CO2 formation rate below the ignition temperature reveals the reduced samples to be significantly more active based on mass unit and shows lower apparent activation energy than the activated oxidized sample. Micro-spot X-ray photoelectron spectroscopy (XPS) and XPS microscopy experiments were carried out on a Ru(0001) single crystal exposed to oxygen at different temperature. Although low energy electron diffraction (LEED) images show a strong 1×1 pattern, the XPS data indicated a wide lateral inhomogeneity with different degree of oxygen dissolved in the subsurface layers. All these and the literature data are discussed in the context of different active states and transport issues, and the metastable nature of a phase mixture under conditions of high catalytic activity.
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Affiliation(s)
| | - Frank Girgsdies
- Fritz-Haber-Institute of the MPG, Department of Inorganic Chemistry, Berlin, Deutschland
| | - Olaf Timpe
- Fritz-Haber-Institute of the MPG, Department of Inorganic Chemistry, Berlin, Deutschland
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