Kinetic assessment of catalysts for the methanolysis of sodium borohydride for hydrogen generation / C.-t. F. Lo in Industrial & engineering chemistry research, Vol. 48 N° 11 (Juin 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5177–5184 Titre : Kinetic assessment of catalysts for the methanolysis of sodium borohydride for hydrogen generation Type de document : texte imprimé Auteurs : C.-t. F. Lo, Auteur ; K. Karan, Auteur ; B. R. Davis, Auteur Année de publication : 2009 Article en page(s) : pp. 5177–5184 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Sodium borohydride Metal chlorides Platinum-coated lithium cobalt oxide Methanolysis Résumé : The efficacy of metal chlorides and platinum-coated lithium cobalt oxide as catalysts for the methanolysis of sodium borohydride over 45 to −20 °C was investigated. Among the metal chlorides tested, cobalt chloride exhibited maximum activity. In the presence of metal chlorides, the methanolysis reaction exhibited first-order kinetics with respect to the borohydride concentration. The rate constant for methanolysis reaction at −20 °C for 10 wt% cobalt chloride was determined to be 0.00136 s−1, which represents an over 100 times increase compared to the kinetics of the noncatalyzed methanolysis reaction. Platinum-coated lithium cobalt oxide also exhibits a significant rate increase compared to uncatalyzed methanolysis reaction at at 20 °C; however, no measurable activity was noticed at −20 °C. Further, the reaction kinetics appear to be zeroth-order with respect to borohydride concentration. In addition to the rate enhancement, all potential catalysts tested in this study showed a significant reduction in the lag time to less than 5 min at all temperatures. The activity of both cobalt chloride and platinum-coated lithium cobalt oxide were examined over several cycles and both catalysts had a reduced activity after the first cycle; however, the rate of hydrogen generation remained stable for the subsequent cycles. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8009186 [article] Kinetic assessment of catalysts for the methanolysis of sodium borohydride for hydrogen generation [texte imprimé] / C.-t. F. Lo, Auteur ; K. Karan, Auteur ; B. R. Davis, Auteur . - 2009 . - pp. 5177–5184. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5177–5184 Mots-clés : Sodium borohydride Metal chlorides Platinum-coated lithium cobalt oxide Methanolysis Résumé : The efficacy of metal chlorides and platinum-coated lithium cobalt oxide as catalysts for the methanolysis of sodium borohydride over 45 to −20 °C was investigated. Among the metal chlorides tested, cobalt chloride exhibited maximum activity. In the presence of metal chlorides, the methanolysis reaction exhibited first-order kinetics with respect to the borohydride concentration. The rate constant for methanolysis reaction at −20 °C for 10 wt% cobalt chloride was determined to be 0.00136 s−1, which represents an over 100 times increase compared to the kinetics of the noncatalyzed methanolysis reaction. Platinum-coated lithium cobalt oxide also exhibits a significant rate increase compared to uncatalyzed methanolysis reaction at at 20 °C; however, no measurable activity was noticed at −20 °C. Further, the reaction kinetics appear to be zeroth-order with respect to borohydride concentration. In addition to the rate enhancement, all potential catalysts tested in this study showed a significant reduction in the lag time to less than 5 min at all temperatures. The activity of both cobalt chloride and platinum-coated lithium cobalt oxide were examined over several cycles and both catalysts had a reduced activity after the first cycle; however, the rate of hydrogen generation remained stable for the subsequent cycles. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8009186

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