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Synthesis and Support Shape Effects on the Catalytic Activities of CuOx/CeO2 Nanomaterials

Zell, Elizabeth Theresa
http://rave.ohiolink.edu/etdc/view?acc_num=ysu1525699148756394

Abstract Details

2018, Doctor of Philosophy in Materials Science and Engineering, Youngstown State University, Department of Chemistry.
In this dissertation, the research focused on the preparation of shape-controlled cerium oxide (CeO2), a known active catalyst support, to investigate the structure-property relationship for CO oxidation reaction. The use of surfactants during synthesis of shape-controlled oxide supports can have an adverse effect on the catalytic activity. Thus, CeO2 of different morphologies (nanorods, nanocubes, and nano-octahedra) were synthesized using a hydrothermal method without an addition of surfactants in the solution. Since the size has a strong effect on differences in geometric and/or electronic properties of catalyst supports effects on the adsorption and activation of CO (carbon monoxide) and molecular oxygen are also known to take place. We strive to understand if there is a correlation with the nano-catalyst’s shapes with different termination planes and the catalytic activity. Furthermore, the research focused on the impregnation of cost-effective metal catalysts with a higher known abundance on the planet. The different morphologies of CeO2 supports were impregnated with copper oxide (CuO) at varying wt.% (1, 5 and 10 wt.%) using a wet incipient method. The samples were oxidized and reduced in order to garner a better understanding of the reducibility effect. The catalysts were then investigated to correlate the increased catalytic activities with the various shapes and defects. CuO/CeO2 and CuOx/CeO2 were characterized using Raman spectroscopy, X-ray Photoelectron Spectroscopy (XPS), X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). The catalytic activities were measured using Temperature Programmed Reduction (TPR), Temperature Programmed Oxidation (TPO), Temperature Programmed Desorption (TPD), and CO oxidation reaction. The results showed that CeO2 nanorods were the superior shape regarding enhancing the catalytic v activity due to its increased surface area and surface defects. CuO catalyst impregnated on CeO2 nanorods with increased surface defects demonstrated improved CO oxidation and low reduction temperatures. Additionally, a systematic study of various bimetal oxides and bimetallic nano-catalysts (Fe-CuO, Ni-CuO, Mn-CuO and Ag-CuOx) impregnated on shape-controlled CeO2 was investigated to understand the effects of the binary catalyst system on the catalytic efficiencies. This was done while keeping copper as one of the binary metal catalysts, since CuO catalysts showed enhanced catalytic activity. The collected data determined that each of the bimetallic catalyst systems showed an improvement in catalytic activity and an enhancement of the stability as compared to CuO/CeO2 catalysts. To make an in-depth investigation of the interfacial interaction and structure of the CuOx/CeO2, TEM and HRTEM techniques were to characterize CuOx/CeO2 nanorods. The H2-TPR profiles were re-evaluated and offered information on the possible structural analysis as well as indicating reduction temperatures.
Ruigang Wang, PhD (Advisor)
Timothy Wagner, PhD (Committee Member)
Sherri Lovelace-Cameron, PhD (Committee Member)
Tom Oder, PhD (Committee Member)
Clovis Linkous, PhD (Committee Member)
218 p.
Chemistry; Materials Science
Heterogeneous catalyst, CeO2 , CO Oxidation

Recommended Citations

Citations

  • Zell, E. T. (2018). Synthesis and Support Shape Effects on the Catalytic Activities of CuOx/CeO2 Nanomaterials [Doctoral dissertation, Youngstown State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1525699148756394

    APA Style (7th edition)

  • Zell, Elizabeth. Synthesis and Support Shape Effects on the Catalytic Activities of CuOx/CeO2 Nanomaterials. 2018. Youngstown State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ysu1525699148756394.

    MLA Style (8th edition)

  • Zell, Elizabeth. "Synthesis and Support Shape Effects on the Catalytic Activities of CuOx/CeO2 Nanomaterials." Doctoral dissertation, Youngstown State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1525699148756394

    Chicago Manual of Style (17th edition)

ysu1525699148756394
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This open access ETD is published by Youngstown State University and OhioLINK.