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Date of Award
2021
Document Type
Campus Access Dissertation
Degree Name
Doctor of Philosophy in Materials Science and Engineering (PhD)
Administrative Home Department
Department of Materials Science and Engineering
Advisor 1
Yun Hang Hu
Committee Member 1
Stephen A. Hackney
Committee Member 2
Joshua M. Pearce
Committee Member 3
Kazuya Tajiri
Abstract
The development of highly efficient and stable catalysts for dry reforming of methane (DRM) and the revealing of catalyst structural evolution during DRM process are necessary. In this dissertation, the research work was focused on (1) DRM performance enhancement of NiO/MgO solid solution by tuning the crystal particle size of MgO, (2) the effect of NiO/MgO solid solution formation on DRM performance, (3) the structural evolution of NiO/MgO catalyst under long-term DRM operation, and (4) the stabilization of Ni/Al2O3 catalyst by a NiAl2O4 isolation layer for DRM. First, the crystal particle size of MgO was tuned by ball-milling and then exploited to prepare NiO/MgO solid solution catalysts. It was revealed that the catalytic activity of NiO/MgO solid solution catalyst for DRM could be promoted by decreasing MgO crystal size. The structures of NiO/MgO catalysts were correlated with their catalytic performance (Chapter 3). The formation effects of the solid solution catalysts were revealed, including the generation of abundant mesopores, the promotion of CO2 absorption, and the limitation of CO adsorption. Consequently, the solid solution catalysts exhibited the excellent catalytic activity and stability for DRM (Chapter 4). The structural evolution of the NiO/MgO solid solution catalyst was examined with long duration test of DRM. It was demonstrated that Ni nanoparticles (NPs) of the catalyst grow from 5 to 36 nm after the operation for 1500 hours, which was resulted from the Ni exsolution induced by the reactant gas, while no coking was formed on the xxii catalyst. The unique bonds between metallic Ni and Mg were firstly found to play an important role in the superior performance of the catalyst (Chapter 5). It was found that a NiAl2O4 spinel isolation layer could be generated when the Ni/Al2O3 catalyst was treated under a repeated reduction-reaction process. The isolation layer can prevent active Ni sites from the contact to Al2O3 surface, thus enhancing the stability of the catalyst (Chapter 6).
Recommended Citation
Li, Meijia, "HIGHLY EFFICIENT AND STABLE NI-BASED CATALYSTS FOR DRY REFORMING OF METHANE", Campus Access Dissertation, Michigan Technological University, 2021.