Enhancement of Water Splitting Efficiency of TiO2 Nanotube Arrays by Nanostructured Cobalt Oxide Electrocatalyst

Qarechalloo, Shervin | 2016

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 49214 (04)
  4. University: Sharif University of Technology
  5. Department: Solid State
  6. Advisor(s): Naseri, Naimeh
  7. Abstract:
  8. The 21st century is facing two major obstacles on the way of accessing clean and renewable energies: first, the rapidly increasing need to the energy resources; and second, the limitations - as well as side-effects - of the conventional fossil fuels. Meanwhile, the production of the solar hydrogen, through water splitting, has been proposed as a promising solution to find a clean and effective source of energy. This process occurs in photo-electro-chemical systems with the activation energy that lies within the range of visible light. One approach that herewith comes to mind, is to start the process by utilizing semiconductors to absorb the sunlight. In order to overcome the overpotential and increase the efficiency of the system, it is necessary to use an electro-catalyst in addition to the semiconductor. This electro-catalyst is usually chosen among compositions of cobalt, nickel, etc. In order to respond to the needs of mass production and economic efficiency, we will need to be cautious about choosing the appropriate photo- and electro-catalysts. The extensive literature in this area has shown us the benefits of utilizing the nanostructured electro-catalysts that are based on oxide/hydroxide cobalt. In the present study, TiO2 nanotube arrays (TNAs) have been used as photoanodes and the main focus of the research is to optimize and study the effect of electrodeposition conditions on the growth of cobalt oxide nanostructures. 0.05mA and 2000s are chosen as the optimum electrodeposition current and time, respectively, due to examination of different electrodeposition conditions and their effect on the growth of cobalt oxide nanostructures. Under mentioned optimized conditions, cobalt oxide nanoparticles grow with dense and homogeneous seeding. In addition, photoelectrochemical measurements in order to study photoresponse current density, surface potential and charge carrier life time, and also physical characterizations in order to chemical and crystalline structure, optical absorption and surface morphology have been carried out which is explained in details in the present study
  9. Keywords:
  10. Electrocatalysts ; Cobalt Oxide ; Titanium Oxide ; Nanostructure ; Titanium Oxide Nanotube ; Photocatalyst ; Photoelectrochemical Cell

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