Počet záznamů: 1
Ionic diffusion and proton transfer in aqueous solutions of alkali metal salts
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SYSNO ASEP 0485594 Druh ASEP J - Článek v odborném periodiku Zařazení RIV J - Článek v odborném periodiku Poddruh J Článek ve WOS Název Ionic diffusion and proton transfer in aqueous solutions of alkali metal salts Tvůrce(i) Cassone, Giuseppe (BFU-R) ORCID, RID
Creazzo, F. (IT)
Giaquinta, P.V. (IT)
Šponer, Jiří (BFU-R) RID, ORCID
Saija, F. (IT)Celkový počet autorů 5 Zdroj.dok. Physical Chemistry Chemical Physics. - : Royal Society of Chemistry - ISSN 1463-9076
Roč. 19, č. 31 (2017), s. 20420-20429Poč.str. 10 s. Forma vydání Tištěná - P Jazyk dok. eng - angličtina Země vyd. GB - Velká Británie Klíč. slova initio molecular-dynamics ; density-functional theory ; electric-fields ; liquid water Vědní obor RIV CF - Fyzikální chemie a teoretická chemie Obor OECD Physical chemistry Institucionální podpora BFU-R - RVO:68081707 UT WOS 000407763700011 DOI https://doi.org/10.1039/c7cp03663a Anotace We report on a series of ab initio molecular dynamics investigations on LiCl, NaCl, and KCl aqueous solutions under the effect of static electric fields. We have found that although in low-to-moderate field intensity regimes the well-known sequence of cationic mobilities mu(K+) > mu(Na+) > mu(Li+) (i.e., the bigger the cation the higher the mobility) is recovered, from intense field strengths this intuitive rule is no longer verified. In fact, field-induced water molecular dissociations lead to more complex phenomena regulating the standard migration properties of the simplest monovalent cations. The water dissociation threshold is lowered from 0.35 V angstrom(-1) to 0.25 V angstrom(-1) by the presence of charged species in all samples. However, notwithstanding a one-stage process of water ionization and proton conduction takes place at 0.25 V angstrom(-1) in the electrolyte solutions where structure maker' cations are present (i.e., LiCl and NaCl), the KCl aqueous solution shows some hindrance in establishing a proton conductive regime, which is characterized by the same proton conduction threshold of neat water (i.e., 0.35 V angstrom(-1)). In addition, it turns out that protons flow easily in the LiCl (sp = 3.0 S cm(-1)) solution and then in descending order in the NaCl (sp = 2.5 S cm(-1)) and KCl (sp = 2.3 S cm(-1)) electrolyte solutions. The protonic conduction efficiency is thus inversely proportional to the ionic radii of the cations present in the samples. Moreover, Cl- anions act as a sort of protonic well for high field intensities, further lowering the overall proton transfer efficiency of the aqueous solutions. As a consequence, all the recorded protonic conductivities are lower than that for neat water (sp = 7.8 S cm(-1)), which strongly indicates that devices exploiting the proton transfer ability should be designed so as to minimize the presence of ionic impurities. Pracoviště Biofyzikální ústav Kontakt Jana Poláková, polakova@ibp.cz, Tel.: 541 517 244 Rok sběru 2018
Počet záznamů: 1