Insight into Proton Transfer in Phosphotungstic Acid Functionalized Mesoporous Silica-Based Proton Exchange Membrane Fuel Cells.
We have developed for fuel cells a novel proton exchange membrane (PEM) using inorganic phosphotungstic acid (HPW) as proton carrier and mesoporous silica as matrix (HPW-meso-silica) . The proton conductivity measured by electrochemical impedance spectroscopy is 0.11 S cm at 90 °C and 100% relative...
| Publicado en: | Journal of the American Chemical Society Vol. 136; no. 13; pp. 4954 - 4965 |
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| Autores principales: | , , , , , |
| Formato: | Artículo |
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American Chemical Society
4/2/2014
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| Materias: | |
| 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=95619211&site=ehost-live header: @attributes: shortDbName: hlh uiTerm: 95619211 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: 4/2/2014 vid: 136 iid: 13 pid: 997 pub: American Chemical Society artinfo: ui: 95619211 10.1021/ja411268q ppf: 4954 ppct: 11 formats: tig: atl: Insight into Proton Transfer in Phosphotungstic Acid Functionalized Mesoporous Silica-Based Proton Exchange Membrane Fuel Cells. aug: au: Yuhua Zhou Jing Yang Haibin Su Jie Zeng San Ping Jiang Goddard, William A. affil: School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore Institute of High Performance Computing, 1 Fusionopolis Way, Connexis 138632, Singapore Fuels and Energy Technology Institute & Department of Chemical Engineering, Curtin University, Perth, Western Australia 6102, Australia Materials and Process Simulation Center, California Institute of Technology, Pasadena, California 91125, United States su: Proton transfer reactions Phosphotungstic acids Proton exchange membrane fuel cells Silica Humidity sug: subj: Proton transfer reactions Phosphotungstic acids Proton exchange membrane fuel cells Silica Humidity ab: We have developed for fuel cells a novel proton exchange membrane (PEM) using inorganic phosphotungstic acid (HPW) as proton carrier and mesoporous silica as matrix (HPW-meso-silica) . The proton conductivity measured by electrochemical impedance spectroscopy is 0.11 S cm at 90 °C and 100% relative humidity (RH) with a low activation energy of ∼14 kJ mol. In order to determine the energetics associated with proton migration within the HPW-meso-silica PEM and to determine the mechanism of proton hopping, we report density functional theory (DFT) calculations using the generalized gradient approximation (GGA). These DFT calculations revealed that the proton transfer process involves both intramolecular and intermolecular proton transfer pathways. When the adjacent HPWs are close (less than 17.0 Å apart), the calculated activation energy for intramolecular proton transfer within a HPW molecule is higher (29.1-18.8 kJ/mol) than the barrier for intermolecular proton transfer along the hydrogen bond. We find that the overall barrier for proton movement within the HPW-meso-silica membranes is determined by the intramolecular proton transfer pathway, which explains why the proton conductivity remains unchanged when the weight percentage of HPW on meso-silica is above 67 wt %. In contrast, the activation energy of proton transfer on a clean SiO (111) surface is computed to be as high as ∼40 kJ mol, confirming the very low proton conductivity on clean silica surfaces observed experimentally. pubtype: Academic Journal doctype: Article src: R language: English refInfo: copyright: @attributes: flag: Y dt: @attributes: year: 2014 holdings: @attributes: islocal: N |
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