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1
Content available Effect of surface coating with palladium on hydrogen permeability of Pd33Ni52Si15 amorphous alloy membrane
Prochwicz W., Macherzyński W., Paszkiewicz B., Stępień Z.
Optica Applicata
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2016
|
Vol. 46, nr 2
173--179
EN
In the paper, the effect of the surface coating with palladium on hydrogen permeation of a Pd33Ni52Si15 amorphous alloy membrane was investigated. We have measured the hydrogen flow through the melt-spun amorphous membrane covered with palladium film of 10, 20, and 30 nm in thickness. Membranes have been tested in the temperature rage 294–358 K, and at pressure fixed at 102 kPa. We investigate the role of this film thickness on the activation energy for hydrogen permeability. It seemed that a relatively thin layer of the palladium on the surface of the membrane which contains over 30% of this element, should not considerably influence the permeability of the membrane for hydrogen. The membrane hydrogen permeability is correlated to permeation activation energy: the lower activation energy is, the higher permeability is observed. The activation energy for permeation strongly depends on palladium film thickness. The rapid increase of its value was recorded when the film thickness was growing up. As the result, the increase of the film thickness suppressed hydrogen permeability. Our findings are discussed in terms of a potential barrier between the two different phases.
2
Content available remote Stopy palladu z rodem i rutenem jako materiały absorbujące wodór o dużej pojemności absorpcyjnej
Koss U., Hubkowska K., Łukaszewski M., Czerwiński A.
Przemysł Chemiczny
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2015
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T. 94, nr 3
291-295
PL
Omówiono wyniki elektrochemicznych badań absorpcji wodoru w dwuskładnikowych stopach palladu z rodem i rutenem. Wykazano, że maksymalna ilość wodoru zaabsorbowanego w bogatych w Pd stopach Pd-Rh i Pd-Ru jest, odpowiednio, o ok. 13 i 20% większa niż w czystym Pd. Największą zdolność absorpcyjną mają stopy zawierające w głębi ok. 7% at. Rh lub 1% at. Ru. Zachowanie to można wytłumaczyć korzystnym efektem elektronowym wskutek utworzenia stopu. Układy Pd-Rh i Pd-Ru z zaabsorbowanym wodorem mogą być wykorzystane jako materiały elektrodowe do superkondensatorów elektrochemicznych charakteryzujących się wartościami pseudopojemności oraz mocy i energii właściwej porównywalnymi z parametrami innych superkondensatorów typu faradajowskiego.
EN
Binary Pd alloys were prepd. by electrodeposition from baths containingPdCl₂, RhCl₃ or RuCl₃ and HCl on Au wire substrate and used for H₂ electrosorption in acidic soln. The Pd-rich alloys (Rh or Ru contents 7.4% at. Or 0.7% at., resp.) showed higher H₂ absorption capacities the Pd alone (by 13% and 20%, resp.). This fact was explained by a favorable electronic effect due to alloy formation. The alloys with adsorbed H₂ can be used as electrode materials for electrochem. capacitors with the parameters typical for faradaic supercapacitors.
3
Content available remote Hydrogen permeation properties of Pd-coated Pd33Ni52Si15 amorphous alloy membrane
Prochwicz W., Macherzyński W., Paszkiewicz B., Stępień Z. M.
Materials Science Poland
|
2015
|
Vol. 33, No. 1
56--58
EN
The vast majority of experimental techniques used for the measurements of hydrogen permeability through metallic membranes whose one or both surfaces are covered with a thin Pd film is based on the assumption that a ratio of film-to-membrane thickness is small enough to cause hydrogen flow to be independent of the Pd film thickness. In an attempt to verify this assumption, we have measured the hydrogen flow through the Pd33Ni52Si15 amorphous membrane covered with Pd film of 10, 20, and 30 nm in thickness. Contrary to our expectations, we have found a dramatic decrease in hydrogen flow with the increase in Pd film thickness. Our findings are discussed in terms of potential barrier between the two different phases.
4
Content available remote Metody elektrochemiczne oznaczania składu chemicznego i pomiaru aktywnej elektrochemicznie powierzchni stopów palladu z innymi metalami szlachetnymi
Łukaszewski M., Hubkowska K., Czerwiński A.
Przemysł Chemiczny
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2011
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T. 90, nr 6
1201-1206
5
Content available remote Właściwości elektrochemiczne i charakterystyka powierzchni stopów palladu ze srebrem i miedzią
Drążkiewicz K., Łukaszewski M., Czerwiński A.
Przemysł Chemiczny
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2010
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T. 89, nr 9
1230-1235
6
Content available remote Electric current stimulation of hydrogen diffusion through an amorphous palladium membrane
Prochwicz W., Kolano R., Stepień Z.
Optica Applicata
|
2009
|
Vol. 39, nr 4
799-805
EN
The work presents the results of the diffusion of hydrogen through a membrane made of amorphous palladium alloy in which one of the surfaces was modified with a layer of carbon nanotubes. We used an amorphous membrane made with a single roller spinning technique. The measurements were performed at ambient temperature. In this work, an attempt was made to study the impact of the flow of electric charge on the diffusion of hydrogen through thus modified amorphous palladium alloy membrane.
7
Analysis of Deuterium Permeation through Pd81Pt19 Alloy at Stress Conditions
Dudek D.
Polish Journal of Chemistry
|
2008
|
Vol. 82, nr 10
1941-1947
EN
The permeation of deuterium through Pd81Pt19 membrane at stress conditions was in vestigated at constant temperature T = 278.2 K in pressures up to 900 hPa(D2). The permeation curves were determined at different initial and boundary conditions in experimental system. The deuterium fluxes were calculated by fitting experimental points with a straight lines in the stationary parts of permeation curves. It has been showed that the deuterium permeation through the Pd81Pt19 mem brane is changed by stresses created in processes of metal lattice expansion.
8
Content available remote Elektrochemiczne badania absorpcji wodoru w palladzie i jego stopach z innymi metalami szlachetnymi
Łukaszewski M., Grdeń M., Czerwiński A.
Przemysł Chemiczny
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2007
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T. 86, nr 2
137-142
9
Cyclic Voltammetric, Chronoamperometric and Quartz Crystal Microbalance Study on Hydrogen Absorption into and Dissolution of Pd and Pd-noble Metal Alloys
Łukaszewski M., Czerwiński A.
Polish Journal of Chemistry
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2007
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Vol. 81, nr 5-6
847-864
EN
Hydrogen absorption into and electrochemical dissolution of thin Pd and Pd alloy (Pd–Au, Pd–Rh) layers have been studied in acidic solutions (0.5MH2SO4) with the use of cyclic voltammetry (CV) and chronoamperometry (CA) coupled with the electrochemical quartz crystal microbalance (EQCM). Currents due to hydrogen adsorption and absorption in alfa- and beta-phase are distinguished on CV curves. The amount of absorbed hydrogen depends on electrode potential and increases with the potential decrease. Hydrogen absorbed in Pd–Au and Pd–Rh alloys is oxidized at a lower potential than in the case of pure Pd. In the case of the Pd–Au system the potential region of phase transition is shifted positively in comparison with Pd indicating higher stability of the beta-phase, while for the Pd–Rh system the potential region of phase transition is shifted negatively indicating lower stability of the beta-phase.Hydrogen absorption is accompanied by stresses inside Pd crystal lattice, both phenomena affecting theEQCMresponse.EQCMexperiments indicate that the magnitude and distribution of stresses are different for absorption and desorption processes, which seems to confirm the important role of the stress effect in the phenomenon of absorption/desorption hysteresis. Pd dissolves electrochemically during polarization to sufficiently high potentials in a CV experiment. The amount of dissolved metal increases with an increase in electrode potential and a decrease in scan rate. Due to Pd preferential dissolution during potential cycling of Pd–Au alloys both cyclic voltammogram and frequency-potential response transform towards curves typical of Au electrode.
10
Content available remote Wpływ tlenków węgla na absorpcję wodoru w stopach palladu
Czerwiński A., Łukaszewski M., Grdeń M., Siwek H.
Przemysł Chemiczny
|
2004
|
T. 83, nr 10
508-512
PL
Omówiono wyniki badań elektrochemicznych właściwości dwu- i trójskładnikowych stopów palladu z platyną i rodem, w szczególności dotyczących absorpcji wodoru w tych układach. Przedstawiono główne aspekty adsorpcji tlenków węgla na metalach z grupy platyny i ich stopach. Wykazano różnorodny wpływ adsorpcji CO i CO2 na procesy absorpcji, adsorpcji i desorpcji wodoru w układzie trójskładnikowym Pd-Pt-Rh.
EN
Cyclic voltammograms were recorded in 0.5 H2SO4for Pd, Pt, Rh, Pd-Pt (6 at.% on surface), Pd-Rh (62 at.% on surface), Pd-Pt (60 at.% on surface) before and after 30-min adsorption of CO2, Pd-Rh (78 at.% on surface) before and after 45-min adsorption of CO2, for a ternary alloy (81:6:13 at.%) Pd -Pt-Rh, and for a ternary (44:35:21 at.%) Pd -Pt Rh alloy before and after 15-min adsorption of CO. The absorption, adsorption and desorption of hydrogen was strongly inhibited by CO. Absorption of hydrogen on the Pd alloys was not affected by CO2 which was adsorbed only on the Pt and Rh surface atoms, and not on the Pd atoms. The different behavior of CO and CO2 enables the activity of individual surface centers in Pd alloys to be distinguished in the reactions involving adsorbed hydrogen. The CO and CO2adsorption products are different. 23 refs.
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