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Electrochemical and Photocatalytic Oxidation of Hydrocarbons

Rismanchian, Azadeh
http://rave.ohiolink.edu/etdc/view?acc_num=akron1415799133

Abstract Details

2014, Doctor of Philosophy, University of Akron, Polymer Science.
This study demonstrates the development of a stable anode for electrochemical oxidation of hydrocarbons in solid oxide fuel cell (SOFC) and a highly active TiO2 based catalyst for photocatalytic reactions. The Ni/YSZ anode of SOFC was modified by Cu electroless plating. The catalytic activity toward H2 and CH4 oxidation were compared by the Faraday resistance (RF) obtained from the impedance spectroscopy. The RF ratio of Cu-Ni/YSZ in CH4 to H2 was greater than that of Ni/YSZ, indicating low catalytic activity of Cu-Ni/YSZ toward CH4 oxidation. The addition of Cu decreased the catalytic activity, but increased stability to 138 h in dry CH4. Characterization of the carbon type with Raman spectroscopy and temperature programmed oxidation showed that Cu formed disordered carbon rather than graphitic carbon which is the precursor to coking. Addition of CO2 to CH4 was studied as another approach to prevent coking. Electrochemical performance and mass spectrometry of the reactor effluent showed that the CH4-CO2 SOFC generated electricity from CO and H2, products of dry reforming reaction, with CO as the major contributor to current generation. CH4-CO2 decreased the activation polarization but showed a limiting current due to the fuel depletion at the interlayer-electrolyte interface. Anode interlayer was modified by reducing the particle size to 2 µm. The fine microstructure increased the three phase boundary length and reduced the activation polarization. The pore loss in the fine microstructure resulted in diffusion limitation and a limiting current in CH4 which was eliminated by adding 4 wt% of pore former at interlayer. Further addition of pore former lowered the performance by creating discontinuity at electrolyte-interlayer interface. The photocatalytic oxidation of ethanol on TiO2 and TiO2 modified with Ag and Au nanoparticles was studied by in-situ IR spectroscopy. Au and Ag increased the surface hydroxyl groups, which further served as active species to oxidize ethanol. Higher rate of electron transfer to Au than to Ag, evidenced by IR spectroscopy, resulted in higher rate of oxidation in Au-TiO2. This resulted in formation of formate (HCOO) on Au-TiO2 and acetate (CH3COO) on Ag-TiO2 as the major intermediate during the initial period of the photocatalytic oxidation.
Steven Chuang, Dr (Advisor)
Darrell Reneker, Dr (Committee Member)
Yu Zhu, Dr (Committee Member)
Xiong Gong, Dr (Committee Member)
Homero Castaneda-Lopez, Dr (Committee Member)
169 p.
Chemical Engineering; Energy
SOFC; Cu electroless plating; Raman spectroscopy; carbon type in CH4-SOFC; impedance spectroscopy; Faraday resistance; limiting current in CH4-CO2; interlayer microstructure; Photocatalytic oxidation on TiO2; in-situ IR spectroscopy; Au and Ag co-catalyst

Recommended Citations

Citations

  • Rismanchian, A. (2014). Electrochemical and Photocatalytic Oxidation of Hydrocarbons [Doctoral dissertation, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1415799133

    APA Style (7th edition)

  • Rismanchian, Azadeh. Electrochemical and Photocatalytic Oxidation of Hydrocarbons. 2014. University of Akron, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1415799133.

    MLA Style (8th edition)

  • Rismanchian, Azadeh. "Electrochemical and Photocatalytic Oxidation of Hydrocarbons." Doctoral dissertation, University of Akron, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1415799133

    Chicago Manual of Style (17th edition)

akron1415799133
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This open access ETD is published by University of Akron and OhioLINK.
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