Investigaion Properties of Electrocatalytic Transition Metal Chalcogenids Nanocomposite in Hydrogen and Oxygen Evolution Reactions

Moazzeni, Mohammad | 2021

153 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 55372 (03)
  4. University: Sharif University of Technology
  5. Department: Chemistry
  6. Advisor(s): Taherinia, Davood
  7. Abstract:
  8. Electrochemical water splitting which consists of two half-reactions, namely; the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER), is an important process in electrochemical energy storage and sustainable production of energy. Therefore, the development of cost-effective and efficient electrocatalysts for water splitting has attracted a lot of interest. In this work, a new nanocomposite was prepared from cobalt diselenide and cerium (IV) oxide derived from calcination of a cerium-based metal-organic framework (Ce-MOF), via hydrothermal and electrodeposition methods. The structure and morphology of synthesized materials were investigated by XRD, FE-SEM, EDX, and BET techniques. The mass ratios of the cobalt diselenide and cerium (IV) oxide in the nanocomposite were optimized to reach the highest activity in OER. The CoSe2/CeO2 nanocomposite with a mass ratio of 5:1 showed the best electrocatalytic performance, with a measured overpotential of 292 mV at the current density of 10 mA cm−2 and a Tafel slope of 59.7 mV dec−1 in OER. In addition, this nanocomposite exhibited an excellent long-term electrochemical stability for 22.5 h. In the electrodeposition method, CoSe2 nanoparticles were deposited at a constant potential on the surface of a glassy carbon electrode (GCE) modified with cerium (IV) oxide (obtained from the calcination of Ce-MOF). The nanocomposite obtained after electrolysis for 850 s showed the best OER performance, with a measured overpotential of 288 mV at the current density of 10 mA cm−2 and a Tafel slope of 42.7 mV dec−1. These numbers are comparable to some of the best electrocatalysts known to date for OER.

  9. Keywords:
  10. Electrochemical Water Splitting ; Electrocatalysts ; Nanocomposite ; Hydrogen Evolution ; Metal-Organic Framework ; Oxygen Evolution ; Composite Membrane based on Metal Organic Framework (MOF) ; Cobalt Diselenide Hybride Nanocomposite

 Digital Object List