P. Millet, C. Lebouin, R. Ngameni, A. Ranjbari, M. Guymont
{"title":"LaNi5的氢化反应:激活过程中热力学状态与吸附动力学的关系","authors":"P. Millet, C. Lebouin, R. Ngameni, A. Ranjbari, M. Guymont","doi":"10.1155/2008/346545","DOIUrl":null,"url":null,"abstract":"This research work concerns the hydriding reaction of LaNi5 during the first hydriding cycles (activation process). Step-by-step sorption isotherms (Δ[H/M]≈0.03) were measured at 298 K, in the composition range 0<H/M<2.0, at the beginning (first hydriding cycle, where hysteresis is maximum) and at the end (tenth hydriding cycle, where hysteresis is minimum) of the activation process, offering the possibility to correlate thermodynamic states (pressure-composition data points) to sorption kinetics. Using pneumatochemical impedance spectroscopy (PIS), experimental impedance diagrams were obtained for each data point of the isotherms. Microscopic rate parameters such as surface resistance and hydrogen diffusion coefficient were obtained as a function of composition, by fitting appropriate model equations to experimental impedances. It is found that the high-frequency pneumatochemical resistance significantly decreases during activation. This is correlated with the surface increase of the solid-gas interface area. The hydrogen diffusion coefficient is found to be larger at the beginning of the activation process and lower on a fully activated sample.","PeriodicalId":229171,"journal":{"name":"Research Letters in Physical Chemistry","volume":"28 1","pages":"0"},"PeriodicalIF":0.0000,"publicationDate":"2008-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"9","resultStr":"{\"title\":\"Hydriding Reaction of LaNi5: Correlations between Thermodynamic States and Sorption Kinetics during Activation\",\"authors\":\"P. Millet, C. Lebouin, R. Ngameni, A. Ranjbari, M. Guymont\",\"doi\":\"10.1155/2008/346545\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"This research work concerns the hydriding reaction of LaNi5 during the first hydriding cycles (activation process). Step-by-step sorption isotherms (Δ[H/M]≈0.03) were measured at 298 K, in the composition range 0<H/M<2.0, at the beginning (first hydriding cycle, where hysteresis is maximum) and at the end (tenth hydriding cycle, where hysteresis is minimum) of the activation process, offering the possibility to correlate thermodynamic states (pressure-composition data points) to sorption kinetics. Using pneumatochemical impedance spectroscopy (PIS), experimental impedance diagrams were obtained for each data point of the isotherms. Microscopic rate parameters such as surface resistance and hydrogen diffusion coefficient were obtained as a function of composition, by fitting appropriate model equations to experimental impedances. It is found that the high-frequency pneumatochemical resistance significantly decreases during activation. This is correlated with the surface increase of the solid-gas interface area. The hydrogen diffusion coefficient is found to be larger at the beginning of the activation process and lower on a fully activated sample.\",\"PeriodicalId\":229171,\"journal\":{\"name\":\"Research Letters in Physical Chemistry\",\"volume\":\"28 1\",\"pages\":\"0\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2008-04-29\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"9\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Research Letters in Physical Chemistry\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.1155/2008/346545\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Research Letters in Physical Chemistry","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1155/2008/346545","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
Hydriding Reaction of LaNi5: Correlations between Thermodynamic States and Sorption Kinetics during Activation
This research work concerns the hydriding reaction of LaNi5 during the first hydriding cycles (activation process). Step-by-step sorption isotherms (Δ[H/M]≈0.03) were measured at 298 K, in the composition range 0