Hydrogen absorption and desorption in the Mg-Ag system

Autores
Urretavizcaya, Guillermina; Sarmiento Chavez, Ana Carolina; Castro, Facundo
Año de publicación
2014
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
We analyze hydrogen absorption and desorption in Mg and Mg?Ag compounds prepared by mechanical milling. The materials were obtained by processing mixtures of Mg or MgH2 with different proportions of Ag under Ar or H2 atmosphere.We observe that Ag and AgMg destabilize MgH2. In the first case the products of the reaction of Ag and MgH2 are AgMg and H2, in the second case MgH2 reacts with AgMg to give AgMg4 and H2. The first reaction was only observed in the forward direction, whereas the second one was registered in both directions. The impossibility to reverse the first reaction was attributed to poor kinetics and experimental limitations. The reversible destabilization induced by AgMg is low, MgH2 overall dehydriding enthalpy is reduced from 76.5 kJ/mol H2 to 69.1 kJ/mol H2. This last value allowed us to estimate the formation enthalpy of AgMg4 at _59.5 kJ/mol. Besides destabilization, a slight improvement in hydrogen absorption kinetics and a more noticeable enhancement in desorption kinetics has been observed in samples containing Ag as an additive. During thermal desorption, the dehydriding temperature decreases by 20 _C. In isothermal desorption experiments at 325 _C, the characteristic induction period of MgH2 without additive practically disappears, and the time to reach 50% of conversion decreases from 17 min to 5.4 min when silver is present. The changes in desorption kinetics could be attributed to AgMg or the interfaces MgH2/AgMg acting as nucleation sites for Mg.
Fil: Urretavizcaya, Guillermina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Sarmiento Chavez, Ana Carolina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Castro, Facundo. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Materia
Hydrogen Absorbing Materials
Intermetallics
Mechanical Milling
Thermodynamic Destabilization
Reaction Pathway
Kinetics
Nivel de accesibilidad
acceso abierto
Condiciones de uso
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
Repositorio
CONICET Digital (CONICET)
Institución
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identificador
oai:ri.conicet.gov.ar:11336/30867
Acceder
id CONICETDig_40fa33a7808991b7224e7b70c636fa87
oai_identifier_str oai:ri.conicet.gov.ar:11336/30867
network_acronym_str CONICETDig
repository_id_str 3498
network_name_str CONICET Digital (CONICET)
spelling Hydrogen absorption and desorption in the Mg-Ag systemUrretavizcaya, GuillerminaSarmiento Chavez, Ana CarolinaCastro, FacundoHydrogen Absorbing MaterialsIntermetallicsMechanical MillingThermodynamic DestabilizationReaction PathwayKineticsWe analyze hydrogen absorption and desorption in Mg and Mg?Ag compounds prepared by mechanical milling. The materials were obtained by processing mixtures of Mg or MgH2 with different proportions of Ag under Ar or H2 atmosphere.We observe that Ag and AgMg destabilize MgH2. In the first case the products of the reaction of Ag and MgH2 are AgMg and H2, in the second case MgH2 reacts with AgMg to give AgMg4 and H2. The first reaction was only observed in the forward direction, whereas the second one was registered in both directions. The impossibility to reverse the first reaction was attributed to poor kinetics and experimental limitations. The reversible destabilization induced by AgMg is low, MgH2 overall dehydriding enthalpy is reduced from 76.5 kJ/mol H2 to 69.1 kJ/mol H2. This last value allowed us to estimate the formation enthalpy of AgMg4 at _59.5 kJ/mol. Besides destabilization, a slight improvement in hydrogen absorption kinetics and a more noticeable enhancement in desorption kinetics has been observed in samples containing Ag as an additive. During thermal desorption, the dehydriding temperature decreases by 20 _C. In isothermal desorption experiments at 325 _C, the characteristic induction period of MgH2 without additive practically disappears, and the time to reach 50% of conversion decreases from 17 min to 5.4 min when silver is present. The changes in desorption kinetics could be attributed to AgMg or the interfaces MgH2/AgMg acting as nucleation sites for Mg.Fil: Urretavizcaya, Guillermina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sarmiento Chavez, Ana Carolina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Castro, Facundo. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaElsevier Science Sa2014-05-22info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/30867Castro, Facundo; Sarmiento Chavez, Ana Carolina; Urretavizcaya, Guillermina; Hydrogen absorption and desorption in the Mg-Ag system; Elsevier Science Sa; Journal of Alloys and Compounds; 611; 2014; 22-5-2014; 202-2090925-8388CONICET DigitalCONICETenginfo:eu-repo/semantics/altIdentifier/url/http://www.sciencedirect.com/science/article/pii/S0925838814011414?via%3Dihubinfo:eu-repo/semantics/altIdentifier/doi/10.1016/j.jallcom.2014.05.066info:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-sa/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-10T13:09:28Zoai:ri.conicet.gov.ar:11336/30867instacron:CONICETInstitucionalhttp://ri.conicet.gov.ar/Organismo científico-tecnológicoNo correspondehttp://ri.conicet.gov.ar/oai/requestdasensio@conicet.gov.ar; lcarlino@conicet.gov.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:34982025-09-10 13:09:29.103CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse
dc.title.none.fl_str_mv Hydrogen absorption and desorption in the Mg-Ag system
title Hydrogen absorption and desorption in the Mg-Ag system
spellingShingle Hydrogen absorption and desorption in the Mg-Ag system
Urretavizcaya, Guillermina
Hydrogen Absorbing Materials
Intermetallics
Mechanical Milling
Thermodynamic Destabilization
Reaction Pathway
Kinetics
title_short Hydrogen absorption and desorption in the Mg-Ag system
title_full Hydrogen absorption and desorption in the Mg-Ag system
title_fullStr Hydrogen absorption and desorption in the Mg-Ag system
title_full_unstemmed Hydrogen absorption and desorption in the Mg-Ag system
title_sort Hydrogen absorption and desorption in the Mg-Ag system
dc.creator.none.fl_str_mv Urretavizcaya, Guillermina
Sarmiento Chavez, Ana Carolina
Castro, Facundo
author Urretavizcaya, Guillermina
author_facet Urretavizcaya, Guillermina
Sarmiento Chavez, Ana Carolina
Castro, Facundo
author_role author
author2 Sarmiento Chavez, Ana Carolina
Castro, Facundo
author2_role author
author
dc.subject.none.fl_str_mv Hydrogen Absorbing Materials
Intermetallics
Mechanical Milling
Thermodynamic Destabilization
Reaction Pathway
Kinetics
topic Hydrogen Absorbing Materials
Intermetallics
Mechanical Milling
Thermodynamic Destabilization
Reaction Pathway
Kinetics
dc.description.none.fl_txt_mv We analyze hydrogen absorption and desorption in Mg and Mg?Ag compounds prepared by mechanical milling. The materials were obtained by processing mixtures of Mg or MgH2 with different proportions of Ag under Ar or H2 atmosphere.We observe that Ag and AgMg destabilize MgH2. In the first case the products of the reaction of Ag and MgH2 are AgMg and H2, in the second case MgH2 reacts with AgMg to give AgMg4 and H2. The first reaction was only observed in the forward direction, whereas the second one was registered in both directions. The impossibility to reverse the first reaction was attributed to poor kinetics and experimental limitations. The reversible destabilization induced by AgMg is low, MgH2 overall dehydriding enthalpy is reduced from 76.5 kJ/mol H2 to 69.1 kJ/mol H2. This last value allowed us to estimate the formation enthalpy of AgMg4 at _59.5 kJ/mol. Besides destabilization, a slight improvement in hydrogen absorption kinetics and a more noticeable enhancement in desorption kinetics has been observed in samples containing Ag as an additive. During thermal desorption, the dehydriding temperature decreases by 20 _C. In isothermal desorption experiments at 325 _C, the characteristic induction period of MgH2 without additive practically disappears, and the time to reach 50% of conversion decreases from 17 min to 5.4 min when silver is present. The changes in desorption kinetics could be attributed to AgMg or the interfaces MgH2/AgMg acting as nucleation sites for Mg.
Fil: Urretavizcaya, Guillermina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Sarmiento Chavez, Ana Carolina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Castro, Facundo. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
description We analyze hydrogen absorption and desorption in Mg and Mg?Ag compounds prepared by mechanical milling. The materials were obtained by processing mixtures of Mg or MgH2 with different proportions of Ag under Ar or H2 atmosphere.We observe that Ag and AgMg destabilize MgH2. In the first case the products of the reaction of Ag and MgH2 are AgMg and H2, in the second case MgH2 reacts with AgMg to give AgMg4 and H2. The first reaction was only observed in the forward direction, whereas the second one was registered in both directions. The impossibility to reverse the first reaction was attributed to poor kinetics and experimental limitations. The reversible destabilization induced by AgMg is low, MgH2 overall dehydriding enthalpy is reduced from 76.5 kJ/mol H2 to 69.1 kJ/mol H2. This last value allowed us to estimate the formation enthalpy of AgMg4 at _59.5 kJ/mol. Besides destabilization, a slight improvement in hydrogen absorption kinetics and a more noticeable enhancement in desorption kinetics has been observed in samples containing Ag as an additive. During thermal desorption, the dehydriding temperature decreases by 20 _C. In isothermal desorption experiments at 325 _C, the characteristic induction period of MgH2 without additive practically disappears, and the time to reach 50% of conversion decreases from 17 min to 5.4 min when silver is present. The changes in desorption kinetics could be attributed to AgMg or the interfaces MgH2/AgMg acting as nucleation sites for Mg.
publishDate 2014
dc.date.none.fl_str_mv 2014-05-22
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
http://purl.org/coar/resource_type/c_6501
info:ar-repo/semantics/articulo
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/11336/30867
Castro, Facundo; Sarmiento Chavez, Ana Carolina; Urretavizcaya, Guillermina; Hydrogen absorption and desorption in the Mg-Ag system; Elsevier Science Sa; Journal of Alloys and Compounds; 611; 2014; 22-5-2014; 202-209
0925-8388
CONICET Digital
CONICET
url http://hdl.handle.net/11336/30867
identifier_str_mv Castro, Facundo; Sarmiento Chavez, Ana Carolina; Urretavizcaya, Guillermina; Hydrogen absorption and desorption in the Mg-Ag system; Elsevier Science Sa; Journal of Alloys and Compounds; 611; 2014; 22-5-2014; 202-209
0925-8388
CONICET Digital
CONICET
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/url/http://www.sciencedirect.com/science/article/pii/S0925838814011414?via%3Dihub
info:eu-repo/semantics/altIdentifier/doi/10.1016/j.jallcom.2014.05.066
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
eu_rights_str_mv openAccess
rights_invalid_str_mv https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
dc.format.none.fl_str_mv application/pdf
application/pdf
dc.publisher.none.fl_str_mv Elsevier Science Sa
publisher.none.fl_str_mv Elsevier Science Sa
dc.source.none.fl_str_mv reponame:CONICET Digital (CONICET)
instname:Consejo Nacional de Investigaciones Científicas y Técnicas
reponame_str CONICET Digital (CONICET)
collection CONICET Digital (CONICET)
instname_str Consejo Nacional de Investigaciones Científicas y Técnicas
repository.name.fl_str_mv CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicas
repository.mail.fl_str_mv dasensio@conicet.gov.ar; lcarlino@conicet.gov.ar
_version_ 1842980465634443264
score 12.993085

Publicaciones similares