Characterization of Pd–Ag membranes after exposure to hydrogen flux at high temperatures

Bosko, María Laura; Yepes, David; Irusta, Silvia; Eloy, Pierre; Ruíz, Patricio; Lombardo, E.A.; Cornaglia, Laura María

doi:10.1016/j.memsci.2007.08.031

Cited by 24 publications

(7 citation statements)

References 31 publications

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“…Although materials with a higher permeability than that of Pd are known (e.g., V, Nb, and Ta), expensive Pd and Pd‐based alloys remain the superior membrane materials owing to their favorable surface properties . Although it is well known that embrittlement can be limited by alloying Pd with elements such as Ag, Y, and Cu, the problem of contamination (e.g., competitive adsorption, coking, and sulfur poisoning) remains unsolved. For porous membranes, Pd is also commonly used as a catalytic, dense coating layer.…”

Section: Figurementioning

confidence: 99%

Promotion of Hydrogen Desorption from Palladium Surfaces by Fluoropolymer Coating

et al. 2016

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The catalytic activity of Pd surfaces towards hydrogen desorption was significantly improved by a nanometer‐thin polytetrafluoroethylene (PTFE) layer, as shown by an enhancement in the permeability of a Pd membrane coated on the permeate side. The origin of this effect was found to be due to a lowering of the barrier for hydrogen desorption, as evidenced by a change in the rate‐limiting mechanism of hydrogen permeation through the membrane from desorption (un‐coated) to diffusion controlled. In situ X‐ray photoelectron spectroscopy (XPS) revealed the electronic structure of the sputtered PTFE. Apart from C–Fn subunits (n=1, 2, 3), we found that nonsaturated carbon atoms became hydrogenated during hydrogen permeation, which was indicative of an interaction between Pd and PTFE. This interaction was weak; no Pd−F bonds were formed. We thus attributed the effect to an increase in the hydrophobicity of the surface by the porous PTFE layer and to a promoter effect of hydrogen desorption as a result of electrostatic interactions between chemisorbed hydrogen and physisorbed PTFE.

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Section: Figurementioning

confidence: 99%

Promotion of Hydrogen Desorption from Palladium Surfaces by Fluoropolymer Coating

et al. 2016

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“…1 , Бесогонов В. В. 1,2 , Бурнышев И. Н. Палладий и некоторые его сплавы, имея высокую проницаемость для водорода, могут использоваться в мембранных реакторах для разделения водорода [9,10]. Взаимодействие водорода с оксидом палладия приводит к восстановлению палладия до металлического, изменяя тем самым состав и свойства исходной пленки.…”

Section: применение наноструктурированных пленочных систем для записи и хранения скрытой информацииunclassified

Application of nanostructured film systems for recording and storing hidden information

et al. 2020

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This paper examines Ag-Pd thick films on a ceramic substrate. After local modification of a part of the film, the authors observed a change in the thermo-EMF values. The modification of the Ag-Pd film surface was performed in hydrogen, namely in atomic and molecular hydrogen. For atomic hydrogen modification the films were subjected to cathodic hydrogenation in an electrolyte solution (H 2 SO 4 ) for 1 minute. Modification in molecular gaseous hydrogen was performed at the temperature higher than 60°C. In process of the modification, palladium oxide, which is present in the film, was reduced to a metal. The authors demonstrated that the changes in the chemical composition of the film resulted in the decrease of its total electric resistance from 60 to 2 Ω. Under the effect of laser irradiation the initial and modified films demonstrated different values of the surface thermo-EMF. A negative charge was formed on the part of the Ag-Pd film surface, which can be explained by the phonon drag effect and the diffusion of electrons to the area with lower temperature. Targeted laser action makes possible local modification of separate film areas. It was shown that in case of the modification by the targeted action onto the film surface a sharp change of an electric signal -from 50 to 250 µV -occurred on the boundary between the modified and non-modified areas. The effect observed can be used to obtain a hidden image on the film surface. The authors managed to successively record, read out, and restore the recorded image. Hence, the results of this research demonstrate the possibility of obtaining hidden information carriers based on the film coatings studied.

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“…The contributions of the research group headed by Laura Cornaglia, based on the use of PdAg membranes prepared by electroless plating, are also widely reported in the literature [ 201 , 209 , 212 , 213 , 214 ]. One example is the work published by Bosko et al [ 202 ], in which PdAg supported membranes were prepared by sequential electroless plating on tubular stainless-steel supports with thickness ranged from 20 to 26 μm.…”

Section: Pd-alloy Membranesmentioning

confidence: 99%

Review of Supported Pd-Based Membranes Preparation by Electroless Plating for Ultra-Pure Hydrogen Production

et al. 2018

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In the last years, hydrogen has been considered as a promising energy vector for the oncoming modification of the current energy sector, mainly based on fossil fuels. Hydrogen can be produced from water with no significant pollutant emissions but in the nearest future its production from different hydrocarbon raw materials by thermochemical processes seems to be more feasible. In any case, a mixture of gaseous compounds containing hydrogen is produced, so a further purification step is needed to purify the hydrogen up to required levels accordingly to the final application, i.e., PEM fuel cells. In this mean, membrane technology is one of the available separation options, providing an efficient solution at reasonable cost. Particularly, dense palladium-based membranes have been proposed as an ideal chance in hydrogen purification due to the nearly complete hydrogen selectivity (ideally 100%), high thermal stability and mechanical resistance. Moreover, these membranes can be used in a membrane reactor, offering the possibility to combine both the chemical reaction for hydrogen production and the purification step in a unique device. There are many papers in the literature regarding the preparation of Pd-based membranes, trying to improve the properties of these materials in terms of permeability, thermal and mechanical resistance, poisoning and cost-efficiency. In this review, the most relevant advances in the preparation of supported Pd-based membranes for hydrogen production in recent years are presented. The work is mainly focused in the incorporation of the hydrogen selective layer (palladium or palladium-based alloy) by the electroless plating, since it is one of the most promising alternatives for a real industrial application of these membranes. The information is organized in different sections including: (i) a general introduction; (ii) raw commercial and modified membrane supports; (iii) metal deposition insights by electroless-plating; (iv) trends in preparation of Pd-based alloys, and, finally; (v) some essential concluding remarks in addition to futures perspectives.

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Characterization of Pd–Ag membranes after exposure to hydrogen flux at high temperatures

Cited by 24 publications

References 31 publications

Promotion of Hydrogen Desorption from Palladium Surfaces by Fluoropolymer Coating

Promotion of Hydrogen Desorption from Palladium Surfaces by Fluoropolymer Coating

Application of nanostructured film systems for recording and storing hidden information

Review of Supported Pd-Based Membranes Preparation by Electroless Plating for Ultra-Pure Hydrogen Production

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