Electrochemical promotion of a platinum catalyst supported on the high-temperature proton conductor La0.99Sr0.01NbO4-δ
Data(s) |
31/08/2009
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Resumo |
<p>The recently discovered, high-temperature proton conductor, La<sub>0.99</sub>Sr<sub>0.01</sub>NbO<sub>4-δ</sub>, was used as a support for the electrochemical promotion of a platinum catalyst. Ethylene oxidation was used as a probe reaction in the temperature range 350-450 °C. Moderate non-Faradaic rate modification, attributable to a protonic promoting species, occurred under negative polarisation; some permanent promotion was also observed. In oxidative atmospheres, both the p<sub>O2</sub> of the reaction mixture and the temperature influenced the type and magnitude of the observed rate modification. Rate-enhancement values of up to ρ = 1.4 and Faradaic-efficiency values approaching Λ = -100 were obtained. Promotion was observed under positive polarisation and relatively dry, oxygen-rich atmospheres suggesting that some oxygen ion conductivity may occur under these conditions. Impedance spectroscopy performed in atmospheres of 4 kPa O<sub>2</sub>/N<sub>2</sub> and of 5 kPa H<sub>2</sub>/N<sub>2</sub> under dry and slightly humidified (0.3 kPa H<sub>2</sub>O) conditions indicated that the electrical resistivity is heavily dominated by the grain-boundary response in the temperature range of the EPOC studies; much lower grain-boundary impedances in the wetter conditions are likely to be attributable to proton transport. © 2009 Elsevier B.V. All rights reserved.</p> |
Identificador |
http://dx.doi.org/10.1016/j.cattod.2009.04.025 http://www.scopus.com/inward/record.url?scp=68349146532&partnerID=8YFLogxK |
Idioma(s) |
eng |
Direitos |
info:eu-repo/semantics/restrictedAccess |
Fonte |
Poulidi , D , Mather , G C , Tabacaru , C N , Thursfield , A & Metcalfe , I S 2009 , ' Electrochemical promotion of a platinum catalyst supported on the high-temperature proton conductor La0.99Sr0.01NbO4-δ ' Catalysis Today , vol 146 , no. 3-4 , pp. 279-284 . DOI: 10.1016/j.cattod.2009.04.025 |
Palavras-Chave | #Ceramic proton conductor #Electrochemical promotion #Impedance spectroscopy #Lanthanum niobate #Permanent promotion #/dk/atira/pure/subjectarea/asjc/1500/1503 #Catalysis #/dk/atira/pure/subjectarea/asjc/1600 #Chemistry(all) |
Tipo |
article |