XPS and TEM Studies on the Role of the Support and Alkali Promoter in Ru/MgO and Ru-Cs+/MgO Catalysts for Ammonia Synthesis Full article
| Journal |
The Journal of Physical Chemistry C
ISSN: 1932-7447 , E-ISSN: 1932-7455 |
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| Output data | Year: 2007, Volume: 111, Number: 26, Pages: 9427-9436 Pages count : 10 DOI: 10.1021/jp066970b | ||||
| Tags | Cesium compounds; Characterization; Fermi level; Magnesia; Ruthenium; Wetting; X ray photoelectron spectroscopy | ||||
| Authors |
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| Affiliations |
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Funding (3)
| 1 | Russian Foundation for Basic Research | 02-03-32681 |
| 2 | Президиум РАН | 10.4 |
| 3 | Zamaraev International Charitable Scientific Foundation |
Abstract:
The chemical state of ruthenium in the Ru/MgO and Ru−Cs+/MgO catalysts prepared by the incipient wetness technique with the use of Ru(OH)Cl3 and Cs2CO3 as the catalyst and promoter precursors, respectively, is characterized by X-ray photoelectron spectroscopy (XPS). The influence of the final state effects (the differential charging and variations of the relaxation energy) on the binding energy of Ru 3d5/2 core level measured for supported Ru nanoparticles is estimated by comparison of the Fermi levels and the modified Auger parameters determined for the Ru/MgO and Ru−Cs+/MgO catalysts with the corresponding characteristics of polycrystalline Ru foil. High-resolution transmission electron microscopy (HRTEM) in combination with energy dispersive X-ray (EDX) microanalysis reveals that Ru particles in the Ru−Cs+/MgO catalyst are covered with an amorphous layer containing cesium. XPS data show that the layer subjected to the prolonged treatment with H2 at 450 °C consists of cesium suboxide Cs2+XO. The shift of the Ru 3d5/2 binding energy toward lower values is found for the Ru−Cs+/MgO catalyst (279.7 eV) with respect to metallic Ru (280.2 eV) and the Ru/MgO catalyst (280.5 eV). It is assumed that the shift results from a decrease in the work function of ruthenium under the action of Cs+ cations located on the Ru surface. The data obtained are used to explain the sharp difference in the activities of the Ru/MgO and Ru−Cs+/MgO catalysts for ammonia synthesis at 250−400 °C.
Cite:
Larichev Y.V.
, Moroz B.L.
, Zaikovskii V.I.
, Yunusov S.M.
, Kalyuzhnaya E.S.
, Shur V.B.
, Bukhtiyarov V.I.
XPS and TEM Studies on the Role of the Support and Alkali Promoter in Ru/MgO and Ru-Cs+/MgO Catalysts for Ammonia Synthesis
The Journal of Physical Chemistry C. 2007. V.111. N26. P.9427-9436. DOI: 10.1021/jp066970b WOS Scopus РИНЦ ANCAN OpenAlex
XPS and TEM Studies on the Role of the Support and Alkali Promoter in Ru/MgO and Ru-Cs+/MgO Catalysts for Ammonia Synthesis
The Journal of Physical Chemistry C. 2007. V.111. N26. P.9427-9436. DOI: 10.1021/jp066970b WOS Scopus РИНЦ ANCAN OpenAlex
Dates:
| Submitted: | Oct 24, 2006 |
| Accepted: | Feb 6, 2007 |
| Published online: | Jun 5, 2007 |
| Published print: | Jul 1, 2007 |
Identifiers:
| Web of science: | WOS:000247599300060 |
| Scopus: | 2-s2.0-34547458637 |
| Elibrary: | 13553067 |
| Chemical Abstracts: | 2007:603674 |
| Chemical Abstracts (print): | 147:198162 |
| OpenAlex: | W2137634928 |