Development of Experimental Chamber for Testing High-Temperature Hydrogen Permeation through Metal Foils

Kudiiarov, Viktor N.; Sakvin, Ivan; Garanin, G. V.; Лидер, А. М.

doi:10.3390/met9121314

Cited by 2 publications

(2 citation statements)

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“…[16]. The flux into and through the membrane is measured by a Sieverts‐type method: [ 17–19 ] hydrogen with the pressure p f (feed pressure) is applied at the feed side. The pressure is recorded continuously.…”

Section: Resultsmentioning

confidence: 99%

Bulk Thermodynamics Determines Surface Hydrogen Concentration in Membranes

Billeter

Kazaz

Borgschulte

2022

Adv Materials Inter

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nonconverted reactants. In this step, hydrogen may be separated from the mixture, and reused in the reaction. In a future scenario with hydrogen as a main energy carrier, the separation and/or purification of the energetically costly hydrogen will become even more important. [1][2][3] A promising way is the use of hydrogen selective membranes made of hydrogen absorbing metals, such as Pd and its alloys. [4,5] The permeability of such membranes is determined by the surface properties of both sides (dissociation/recombination) and by the bulk permeability (diffusion and solubility). [4] There has been substantial research effort in finding cheaper materials with a higher permeability than that of Pd (e.g., V, Nb, Ta, and their alloys [6][7][8][9][10] ), however, expensive Pd and Pd based alloys remain the superior membrane materials owing to their favorable surface properties. [5,11] Cheap materials such as V-based alloys will revolutionize the technology, if their surface properties can be modified to match those of Pd. Despite this rather straightforward goal, there is a knowledge gap of what these desirable surface properties are. Most works refer to concepts from surface science which describe the physisorption, dissociation (barrier), and chemisorption of hydrogen. [12] However, additional steps-the hopping to subsurface sites and adjacent bulk sites-are needed to model the permeation process adequately. Nevertheless, due to the complex interaction of steps, the predictive power of modeling is limited [4,6,13] and-more importantly-experimental verification only possible by comparison with very basic experiments (permeation kinetics, e.g. ref.[14]) due to the lack of operando hydrogen analysis.Baldi et al. have demonstrated electron energy loss spectroscopy as an analysis method for bulk hydrogen in nano-particles. [15] In this paper, we further developed the method to be able to probe the surface hydrogen content of hydride thin films in situ by reflecting electron energy loss spectroscopy (REELS). The method is applied in an experimental approach, in which the surface properties of membranes can be intentionally modified and their hydrogen content determined under operating conditions. We demonstrate the existence of a rate-limiting step by direct observation of the dependence of the permeation on the hydrogen content in a Pd/V composite membrane. The modeling yields the relevance of the individual layers, making it possible to link the results to the ones obtained from hydrogen uptakeThe functioning of hydrogen selective metal membranes relies on the finetuned interaction of their surfaces with the inner bulk. The link between hydrogen permeation and surface concentration is unveiled using a novel combination of thin film preparation and surface science analysis to probe and intentionally modify the surface properties of palladium vanadium composite membranes. The in situ preparation allows for observation of ultraclean hydrogenation and the quantification of the permeation as a function of temperature and p...

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Section: Resultsmentioning

confidence: 99%

Bulk Thermodynamics Determines Surface Hydrogen Concentration in Membranes

Billeter

Kazaz

Borgschulte

2022

Adv Materials Inter

View full text Add to dashboard Cite

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“…We have demonstrated a simple method to study the hydrogen gradient in hydrogen absorbing metals by probing the total hydrogen uptake and simultaneously the desorption from a partially sealed membrane. The strength of the method is the simplicity of the experimental setup, consisting of a UHVmembrane setup with established technology [27,36,37] (mass spectrometer, Sieverts method). Such a setup can be combined with additional characterization methods [25].…”

Section: Discussionmentioning

confidence: 99%