Show simple item record

dc.contributor.advisorWay, J. Douglas
dc.contributor.authorPatki, Neil
dc.date.accessioned2017-10-11T17:30:12Z
dc.date.accessioned2022-02-03T12:59:30Z
dc.date.available2017-10-11T17:30:12Z
dc.date.available2022-02-03T12:59:30Z
dc.date.issued2017
dc.identifierPatki_mines_0052E_11354.pdf
dc.identifierT 8363
dc.identifier.urihttps://hdl.handle.net/11124/171791
dc.descriptionIncludes bibliographical references.
dc.description2017 Fall.
dc.description.abstractIn this work, electroless plating (ELP) was used to fabricate thin metal films for hydrogen separation and purification applications. The first section focused on Pd-Au alloy composite membranes because pure Pd was susceptible to sulfur and carbon poisoning which adversely affected the throughput (H2 flux) and selectivity (H2 purity). Dense Pd-Au bilayer films fabricated by sequential ELP of Pd and Au were annealed at different temperatures and pressures of H2 gas to assist in the formation of a homogenous alloy. The highest temperature (550°C) and pressure (3.0MPa H2) reduced the annealing time from five days to nine hours because of a lower activation energy for inter-metallic diffusion. Additionally, there was a need to identify an in situ parameter to confirm annealing as ex situ analysis techniques were too time intensive. This was achieved by calculating the apparent activation energy for H2 permeation (Eact) which had a characteristic value depending on the Au composition. Alloys in the 0–41wt% Au range were annealed and their calculated Eact values were found to agree well with literature data for cold-rolled foils. Eact initially decreased from 12.4 to 7.5kJmol-1 (0 to 21wt% Au) before increasing to 9.0kJmol-1 (41wt% Au). For the second section, it was desired to fabricate cheap and coking resistant anodes on protonic ceramic membranes for hydrogen separation from hydrocarbon-rich feeds. Cu is a good candidate because of its stability at high temperatures in reducing and hydrocarbon-containing gas environments. But Cu electrodes fabricated using commercial pastes are thick (≥10μm) and tend to delaminate from the ceramic. Cu ELP was shown to be a better alternative as thin (~1μm) and well-adhered electrodes were fabricated with Pd, Ru, and Cu as activation catalysts. Amongst them Pd/Cu and Ru/Cu had the lowest area specific resistances (two orders of magnitude lower than the pastes). Furthermore, during galvanic hydrogen pumping, the membrane-electrode assemblies demonstrated high current efficiencies (>80%). Pd/Cu and Ru/Cu also showed low power requirements: ≤34mW/(NmL H2 min-1) in 10%H2 in Ar. However, after testing Pd/Cu in the presence of CH4, the power requirement in 10%H2 in Ar tripled and that change was irreversible.
dc.format.mediumborn digital
dc.format.mediumdoctoral dissertations
dc.languageEnglish
dc.language.isoeng
dc.publisherColorado School of Mines. Arthur Lakes Library
dc.relation.ispartof2017 - Mines Theses & Dissertations
dc.rightsCopyright of the original work is retained by the author.
dc.subjectCu anode
dc.subjectfuel electrode
dc.subjectprotonic ceramic membrane
dc.subjectelectroless plating/deposition
dc.subjectapparent activation energy for hydrogen permeation
dc.subjectPdAu alloy formation
dc.titleCoking resistant Pd-Au composite membranes and Cu-based electrodes by electroless plating for H₂ separation and purification
dc.typeText
dc.contributor.committeememberRicote, Sandrine
dc.contributor.committeememberCarreon, Moises A.
dc.contributor.committeememberO'Hayre, Ryan P.
thesis.degree.nameDoctor of Philosophy (Ph.D.)
thesis.degree.levelDoctoral
thesis.degree.disciplineChemical and Biological Engineering
thesis.degree.grantorColorado School of Mines


Files in this item

Thumbnail
Name:
Patki_mines_0052E_11354.pdf
Size:
9.643Mb
Format:
PDF

This item appears in the following Collection(s)

Show simple item record