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Investigation of Aligned Carbon Nanotubes Modified by Platinum Nanoparticles as Hydrogen Sulfide Sensor

Salmani Rezaie, Salva | 2012

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 42880 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Dolati, Abolghasem; Ghorbani, Mohamad
  7. Abstract:
  8. The present research describes sensing behavior of modified aligned carbon nanotubes toward detection of hydrogen sulfide. Aligned carbon nanotubes were grown on etched stainless steel by thermal chemical vapor deposition. Obtained CNTs have curved closed tips and bamboo like structure. Purification of carbon nanotubes were performed by electrochemical oxidation of CNTs. Potential cycling was applied on grown CNTs in different acid solutions and 0.2 M sulfuric acid was chosen to oxidize the CNTs. Carboxylic functional groups were produced by electrochemical oxidation of CNTs and can be observed in FTIR studies. These groups enhanced the electrochemical properties of electrodes and may act as anchor for platinum electro- deposition. In order to improve sensor behavior surface modification of CNTs were done by platinum electro- deposition. The sensing behavior of electrodes was characterized with cyclic voltammetry method and sulfide oxidation mechanism focused in deep by studying the effect of scan rate on electrochemical response of the electrode .The CNT modified electrode displayed high sensitivity of 461±40 µA/mM in linear rang of 0. 5 -2 mM and CNT/Pt electrode shown sensitivity of 468±38 µA/mM in wide linear rang of 0-5 mM .limit of detection was characterized by current time transient curves. And we have obtained 4.7 µM (0.1 ppmH2S) for the CNT electrode based on standard deviation of response. High sensitivity, low detection limit, wide linear range, good stability and repeatability of the electrodes showed the reliability of aligned carbon nanotubes to perform as hydrogen sulfide sensor.

  9. Keywords:
  10. Platinum Nanoparticle ; Electrochemical Oxidation ; Hydrogen Sulfide Sensor ; Aligned Carbon Nanotubes

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