Synthesis of Earth-Abundant Transition-Metal Based Nanocomposites as Bifunctional Electrocatalysts for the Overall Water Splitting

Hajiloeyan Morafeh, Mojtaba | 2022

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 56045 (03)
  4. University: Sharif University of Technology
  5. Department: Chemistry
  6. Advisor(s): Taherinia, Davoud
  7. Abstract:
  8. Sustainable and renewable energy sources are of fundamental importance in the development of strategic and sustainable economies. Therefore, in recent decades, water electrolysis has been widely used to produce pure hydrogen and oxygen without emitting carbon materials and is considered as a method for producing electrical energy alongside other renewable sources (such as wind and solar energy). Here, we report the synthesis of CoFe double-layered hydroxides (CoFe-LDHs) and their application as electrocatalysts for water splitting in alkaline environments. CoFe-LDHs were prepared via a new hydrothermal route from the metal-organic framework MIL-88A (MOF). The Co to Fe ratio in LDHs was systematically adjusted to enhance their electrocatalytic activity in OER. It was observed that Co0.39Fe0.61-LDH exhibited better electrocatalytic performance compared to other synthesized materials. Specifically, Co0.39Fe0.61-LDH required a potential of 227 mV per 20mA cm-2 with a Tafel slope of 36.8 mV dec-1 for the OER reaction, and a potential of 234 mV per 20mA cm-2 with a Tafel slope of 209 mV dec-1 for the HER reaction, showing considerable electrochemical stability. Additionally, this LDH provided a current density of 600 mA cm-2 at a potential of 284 mV in the OER reaction at an industrial scale. The crystalline structure and morphology of the synthesized nanoparticles were also investigated by XRD and FESEM analyses. Our results indicate that adjusting the metallic content of LDHs is a simple yet effective strategy for enhancing their electrocatalytic activity in water splitting electrochemical reactions
  9. Keywords:
  10. Water Splitting ; Electrocatalysts ; Electrochemical Water Splitting ; Metal-Organic Framework ; Transition Metals ; Compounds Based on Transition Metals ; Abundant Transition Metal ; Water Electrolysis

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