Abstract
In this work, we utilized the concept of decoupling the electrocatalytic
activity from the current conducting phase of solid oxide cell fuel
electrodes to investigate the electrochemical performance of three
different transition metals, namely Ni, Co, and Fe. It was found that
the nickel and cobalt infiltrated cells had comparable performances in
both 4% H2O/H2 and 50% H2O/H2. Furthermore, iron nanoparticles were found to be the better electrocatalyst at low pO2 values, however at higher pO2
values the iron infiltration became the inferior catalyst.
Investigating the temperature dependence of the polarization resistance
in terms of activation energy and pre-exponential factor showed
interesting differences between the metal catalysts and a dependence on
the gas atmosphere. The results were analyzed by developing a model
based on the harmonic oscillator, the model allows for correlating
changes in activation energy and pre-exponential factor with kinetic
parameters of the electrode reaction. The model indicates that at higher
pO2 values, iron nanoparticles experience a surface
blockade, i.e. strong bonding of the reactants to the catalytic sites.
For the nickel electrocatalyst, an increase in steam content according
to the model leads to an increase in the turnover frequency, which is in
good agreement with earlier reports in literature.
Original language | English |
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Article number | 135004 |
Journal | Electrochimica Acta |
Volume | 327 |
Number of pages | 9 |
ISSN | 0013-4686 |
DOIs | |
Publication status | Published - 2019 |
Keywords
- Solid oxide cells
- Infiltration
- Electrocatalytic activity
- Model for adsorption of species
- Nanoparticles
- Fuel electrodes