Mechanism of Ethanol Synthesis from Syngas on Rh(111).
Rh-based catalysts display unique efficiency and selectivity in catalyzing ethanol synthesis from syngas (2C0 + 4H CHOH + HO). Understanding the reaction mechanism at the molecular level is the key to rational design of better catalysts for ethanol synthesis, which is one of major challenges for eth...
| Publicado en: | Journal of the American Chemical Society Vol. 131; no. 36; pp. 13054 - 13062 |
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| Autores principales: | , |
| Formato: | Artículo |
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American Chemical Society
9/16/2009
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| Acceso en línea: | Ver este registro en EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=hlh&AN=44466059&site=ehost-live header: @attributes: shortDbName: hlh uiTerm: 44466059 longDbName: Humanities International Complete uiTag: AN controlInfo: bkinfo: jinfo: jid: 00027863 ACS jtl: Journal of the American Chemical Society issn: 00027863 maglogo: N pubinfo: dt: 9/16/2009 vid: 131 iid: 36 pid: 997 pub: American Chemical Society artinfo: ui: 44466059 10.1021/ja903013x ppf: 13054 ppct: 8 formats: tig: atl: Mechanism of Ethanol Synthesis from Syngas on Rh(111). aug: au: YongMan Choi Ping Liu affil: Chemistry Department, Brookhaven National Laboratory, Upton, New York, 11973 su: Alcohol Hydrogenation Chemical inhibitors Density functionals Chemical research Photosynthetic oxygen evolution sug: subj: Alcohol Hydrogenation Chemical inhibitors Density functionals Chemical research Photosynthetic oxygen evolution ab: Rh-based catalysts display unique efficiency and selectivity in catalyzing ethanol synthesis from syngas (2C0 + 4H CHOH + HO). Understanding the reaction mechanism at the molecular level is the key to rational design of better catalysts for ethanol synthesis, which is one of major challenges for ethanol application in energy. In this work, extensive calculations based on density functional theory (DFT) were carried out to investigate the complex ethanol synthesis on Rh(111). Our results show that ethanol synthesis on Rh(111) starts with formyl formation from CO hydrogenation, followed by subsequent hydrogenation reactions and CO insertion. Three major products are involved in this process: methane, methanol, and ethanol, where the ethanol productivity is low and Rh(111) is highly selective to methane rather than ethanol or methanol. The rate-limiting step of the overall conversion is the hydrogenation of CO to formyl species, while the selectivity to ethanol is controlled by methane formation and C-C bond formation between methyl species and CO. The strong Rh-CO interaction impedes the CO hydrogenation and therefore slows down the overall reaction; however, its high affinity to methyl, oxygen, and acetyl species indeed helps the C-O bond breaking of methoxy species and therefore the direct ethanol synthesis via CO insertion. Our results show that to achieve high productivity and selectivity for ethanol, Rh has to get help from the promoters, which should be able to suppress methane formation and/or boost C-C bond formation. The present study provides the basis to understand and develop novel Rh-based catalysts for ethanol synthesis. pubtype: Academic Journal doctype: Article src: R language: English refInfo: copyright: @attributes: flag: Y dt: @attributes: year: 2009 holdings: @attributes: islocal: N |
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