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Experimental and Theoretical investigation of Electro-oxidation of C1 Compounds on Nickel and Copper Surfaces

Zeinaghaji, Mohammad | 2009

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 40006 (03)
  4. University: Sharif University of Technology
  5. Department: Chemistry
  6. Advisor(s): Gobal, Fereydoon
  7. Abstract:
  8. A study of the electro-oxidation and surface reactions of C1 compounds on Ni and Cu electrodes, Ni(111) and Cu (111) has been performed by methods of cyclic voltammetry, BOC-MP and DFT. The diffusion coefficients and activation energies of the electro-oxidation of methanol and formaldehyde in alkaline solution on Ni electrode have been derived. Values around 2.27×10-6 cm2s-1, 1.98×10-5cm2s-1, 12.15 Kcal mol-1 and 11.65 Kcal mol-1 have been obtained respectively. In theoretical study , the elimination of hydrogen from CH3 and CH2 groups has been proposed as a mechanism in surface reactions of methanol and formaldehyde on Ni(111) respectively. The activation energies of oxidation of methanol and formaldehyde on Ni (111) has been theoretically obtained and are 15.37 and 4.37 kcalmol-1 respectively. The investigation of electro oxidation of formic acid in alkaline solution on Ni electrode indicates that formic acid has inhibitor role. A theoretical study of formic acid reactions on Ni(111) as well as positive ΔH for reactions indicate that surface reactions of formic acid on Ni(111) do not occur. The diffusion coefficients of methanol and formaldehyde in alkaline solution have been obtained as 1.58×10-6 cm2s-1 and 1.85×10-6 cm2s-1 respectively. In theoretical study of surface reactions of methanol on Cu (111) the elimination of hydrogen from CH3 has been proposed as mechanism and the activation energy of around 13 kcalmol-1 has been obtained. Theoretical study of surface reactions of formaldehyde on Cu (111) indicates that the formation of CHOOH intermediate is more favored over CHO. The investigation of electro oxidation of formic acid in alkaline solution on Cu electrode indicates that formic acid has inhibitor role. A theoretical study of formic acid reactions on Cu (111) as well as positive ΔH for reactions indicate that surface reactions of formic acid on cu (111) do not happen.

  9. Keywords:
  10. Nickel ; Copper ; Electro-Oxidation ; Cyclic Voltammetry ; Bond-Order Conservation-Potential Method (DBOC-MP) ; Density Functional Theory (DFT) ; C1 Compounds

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