Abstract
A 3-electrode half-cell setup consisting of a yttria-stabilized zirconia (YSZ) electrolyte support was employed to investigate the chemical and electrochemical processes occurring in the vicinity of a model hybrid direct carbon fuel cell (HDCFC) anode (Ni-YSZ) in contact with a molten carbon-alkali carbonate slurry. Electrochemical testing, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), with and without the Ni-YSZ layer highlighted the promotional effect of the Ni-YSZ anode layer, and revealed the contributions of Ni/NiO, and potentially K/K2O, redox couple(s). Treated anthracite and bituminous coals, as well as carbon black, were tested, revealing similar open circuit potential and activation energies in mixed 96-4vol% N2-CO2 and 50-50vol% CO-CO2 environments between 700 and 800°C. Bituminous coal showed the highest activity, likely associated to a high O/C ratio and hydrogen content. Based on acquired data, a reaction scheme was proposed for processes at the working electrode, including the role of bubble formation in the vicinity of the electrochemically active solid/molten medium interface.
Original language | English |
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Journal | International Journal of Hydrogen Energy |
Volume | 40 |
Issue number | 4 |
Pages (from-to) | 1945–1958 |
ISSN | 0360-3199 |
DOIs | |
Publication status | Published - 2015 |
Keywords
- Bituminous coal
- Carbon dioxide
- Carbon monoxide
- Cyclic voltammetry (CV)
- Direct carbon fuel cell (DCFC)
- Half-cell
- Activation energy
- Carbon black
- Cyclic voltammetry
- Electrochemical impedance spectroscopy
- Electrodes
- Nickel
- Yttria stabilized zirconia
- Zirconia
- Electrochemical process
- Electrochemical testing
- Hydrogen contents
- Open circuit potential
- Promotional effect
- Reaction schemes
- Working electrode
- Yttria-stabilized zirconias (YSZ)
- Direct carbon fuel cells (DCFC)