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Venkov TV, Hess C, Jentoft FC. Redox properties of vanadium ions in SBA-15-supported vanadium oxide: an FTIR spectroscopic study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:1768-77. [PMID: 17279655 DOI: 10.1021/la062269n] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The state of vanadium ions in VxOy/SBA-15 (2.7 wt % V) was studied with FTIR spectroscopy using CO and NO as probe molecules. Neither CO (at 85 K) nor NO (at RT) adsorb on the oxidized sample because of the coordinative saturation of V5+ ions and the covalent character of the V5+=O bond. After treatment of the sample in 50 kPa H2 at 673 K, the V5+ ions are reduced to two different types of V3+ sites, as manifested by carbonyl bands at 2189 and 2177 cm-1. In the presence of O2 at 85 K, thus formed V3+ ions are partly oxidized to V4+ sites showing carbonylic bands at 2202 and 2190 cm-1. When the reduced sample is exposed to O2 at room temperature, the V3+ ions are fully oxidized to V5+. The adsorption of NO on the reduced VxOy/SBA-15 shows that the V3+ and V4+ ions possess two effective coordinative vacancies and as a result can adsorb two NO molecules forming the respective V3+(NO)2 and V4+(NO)2 dinitrosyls. The introduction of O2 to the VxOy/SBA-15-NO system leads to reoxidation of the V3+ and V4+ ions to V5+ and formation of bridged (1639 cm-1) and bidentate (1573 cm-1) surface nitrates. After coadsorption of CO and NO on the reduced sample the formation of surface mixed carbonyl-nitrosyls (2108 and 1723 cm-1) was observed for the first time.
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Affiliation(s)
- Tzvetomir V Venkov
- Department of Inorganic Chemistry, Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
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Concepción P, Knözinger H, López Nieto JM, Martínez-Arias A. Characterization of Supported Vanadium Oxide Catalysts. Nature of the Vanadium Species in Reduced Catalysts. J Phys Chem B 2002. [DOI: 10.1021/jp010918s] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- P. Concepción
- Instituto de Tecnología Química, Universidad Politécnica de Valencia, UPV-CSIC, Avda. Los Naranjos s/n, 46022 Valencia, Spain, Institut für Physikalische Chemie, Universität München, Butenandtstrasse, 5−13 (Haus E), 81377 München, Germany, and Instituto de Catálisis y Petroleoquímica, CSIC-UAM, Cantoblanco, 28049 Madrid, Spain
| | - H. Knözinger
- Instituto de Tecnología Química, Universidad Politécnica de Valencia, UPV-CSIC, Avda. Los Naranjos s/n, 46022 Valencia, Spain, Institut für Physikalische Chemie, Universität München, Butenandtstrasse, 5−13 (Haus E), 81377 München, Germany, and Instituto de Catálisis y Petroleoquímica, CSIC-UAM, Cantoblanco, 28049 Madrid, Spain
| | - J. M. López Nieto
- Instituto de Tecnología Química, Universidad Politécnica de Valencia, UPV-CSIC, Avda. Los Naranjos s/n, 46022 Valencia, Spain, Institut für Physikalische Chemie, Universität München, Butenandtstrasse, 5−13 (Haus E), 81377 München, Germany, and Instituto de Catálisis y Petroleoquímica, CSIC-UAM, Cantoblanco, 28049 Madrid, Spain
| | - A. Martínez-Arias
- Instituto de Tecnología Química, Universidad Politécnica de Valencia, UPV-CSIC, Avda. Los Naranjos s/n, 46022 Valencia, Spain, Institut für Physikalische Chemie, Universität München, Butenandtstrasse, 5−13 (Haus E), 81377 München, Germany, and Instituto de Catálisis y Petroleoquímica, CSIC-UAM, Cantoblanco, 28049 Madrid, Spain
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Koyano G, Saito T, Misono M. In situ vibrational spectroscopic investigation of surface redox process of vanadyl pyrophosphate. ACTA ACUST UNITED AC 2000. [DOI: 10.1016/s1381-1169(99)00317-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Strong Metal–Promoter Oxide Interactions Induced by Calcination in V, Nb, and Ta Oxide Promoted Rh/SiO2Catalysts. J Catal 1997. [DOI: 10.1006/jcat.1997.1583] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Beutel T, Knözinger H, Siborov AV, Zaikovskii VI. Metal–promoter interactions in vanadium oxide promoted Rh/SiO2catalysts. ACTA ACUST UNITED AC 1992. [DOI: 10.1039/ft9928802775] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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