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Fabrication of Multilayer Electrodes Based on Earth-Abundant Transition--Metal Compounds and Investigation of Their Photoelectrocatalytic Properties in Water Splitting Reaction

Nikandish, Milad | 2023

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 55891 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Ghasemian, Saloumeh; Taherinia, Davood
  7. Abstract:
  8. Photoelectrochemical (PEC) water splitting is exceedingly promising for converting solar energy into molecular hydrogen as a clean and sustainable fuel. However, the overall rate of water splitting reaction is severely limited by the sluggish kinetics of the anodic half-reaction, namely, the oxygen evolution reaction (OER). Bismuth vanadate (BiVO4) is a popular photoanode for PEC water splitting due to its high stability, low cost, narrow band gap (2.4 eV), high visible-light absorption, and environmental compatibility. However, BiVO4 suffers from poor charge transfer, fast recombination of electron-hole pairs, and inferior catalytic activity toward OER. An effective strategy to overcome these problems is to load an oxygen evolution co-catalyst (OEC) on the BiVO4 surface. In this study, CoSe2/BiVO4/FTO as a novel and efficient multilayer photoanode for PEC oxidation of water was fabricated and tested. A film of BiVO4 on the FTO substrate was first prepared using a facile electrodeposition method followed by a calcination step. Then, the CoSe2 was coated onto the surface of BiVO4 via an electrodeposition method. Scanning electron microscopy (SEM) revealed that BiVO4 film was uniformly covered with CoSe2. The fabricated photoanode exhibited a remarkable photocurrent density of 6.02 mA/cm2 at 1.23 V vs. RHE in Na2SO4 electrolyte under AM 1.5G illumination, which is more than four times higher than that of bare BiVO4. Moreover, electrochemical impedance spectroscopy showed that CoSe2/BiVO4 possessed a faster charge transfer kinetics compared to BiVO4. These findings indicate that CoSe2/BiVO4/FTO can be employed as a promising photoanode with outstanding performance towards photoelectrochemical OER
  9. Keywords:
  10. photoelectrocatalytic Activity ; Photoelectrochemical Water Splitting ; Oxygen Evoloution Reaction (OER) ; Photoanode Electrode ; Renewable Energy Resources ; Abundant Transition Metal ; Water Oxidation ; Bismuth Vanadate

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