Use this url to cite ETD: https://hdl.handle.net/20.500.12259/124794
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Investigation of the catalytic material diffusion during hydrogenation of Pt-Mg-Ni Thin films
Field of Science
Fizika / Physics (N002)
Type of publication
type::text::thesis::master thesis
Title
Investigation of the catalytic material diffusion during hydrogenation of Pt-Mg-Ni Thin films
Other Title
Katalitinių medžiagų difuzijos hidrinant plonas Pt-Mg-Ni dangas tyrimas
Author
Idowu, Michael Oluwaseun |
Advisor
Extent
46 p.
Date Issued
2015-01-15
Abstract
Mg-Ni alloy thin films have attracted much attention as hydrogen storage materials. The achievable high H-storage capacity and the low absorption and desorption pressures are the advantages of this material. However, because of the high sorption temperature and the relatively slow kinetics the direct use of magnesium is not common. Using catalysts is one direction to optimize the properties. It is important to discover the best catalyst for magnesium-based systems to enhance the kinetics of absorption and desorption. In this thesis work, The aim of the work is to investigate what happens to the Platinum coating which is the catalyst during hydrogenation process of the Magnesium-Nickel samples/films. Three samples of Magnesium and Nickel coatings on Silicon substrate were obtained by magnetron sputtering. Each sample was divided into two equal parts and one part was covered with a catalytically active platinum layer. The coating was hydrogenated using the sky hydrogenation under high hydrogen pressure and temperature technologies. The amount of hydrogen absorption was large upon exposure to hydrogen gas; the films take up hydrogen and become transparent. The platinum layer enhanced the kinetics of hydrogen adsorption and desorption, while also protecting the coatings from further oxidation. It is shown that in spite of all the advantages of platinum after hydrogenation part of the platinum diffused into the Mg-Ni coating structure and in the future it may stop hydrogenation process while trying to realize multiple coatings hydrogenating - dehydrogenating. It was also noted that this diffusion from the Mg-Ni coating initiated the formation of undesirable Mg-Silicates formation.
Šiame darbe, panaudojant magnetroninio garinimo metodą buvo gautos Mg-Ni dangos ant silicio padėklo. Kiekvienas bandinys buvo padalintas į dvi lygias dalis ir viena iš dalių buvo padengtas katalitiškai aktyviu platinos sluoksniu. Dangos buvo hidrintos panaudojant dangų hidrinimo aukštame vandenilio slėgyje ir temperatūroje technologijas. Gauti metalų hidridai buvo skaidrūs ir sluoksnis, kuris buvo padengtas platinos katalizatoriais pademonstravo geresnę hidrinimosi kinetiką. Taigi platinos sluoksnis pasitarnavo kaip hidrinimo proceso aktyvatorius ir kartu apsaugojo Mg-Ni dangas nuo papildomos oksidacijos. Pagrindinis šio darbo tikslas buvo ištirti kas atsitinka su platina Mg-Ni dangų hidrinimo metu. Darbe parodyta, kad nepaisant visų platinos privalumų po hidrinimosi dalis platinos difundavo į Mg-Ni dangos struktūrą ir ateityje tai gali sustabdyti hidrinimosi procesą, siekiant realizuoti daugkartinį dangų hidrinimą – dehidrinimą. Taip pat buvo pastebėta, kad Si difundavo iš padėkliuko į Mg-Ni dangas taip iniciuodamas nepageidautinų Mg – silicidų formavimąsi.
Language
Anglų / English (en)
Defended
Taip / Yes
Access Rights
Atviroji prieiga / Open Access