SOFC is a mature technology suitable for producing potentially clean energy. Understanding the reaction mechanism of a complex H2 - CO fuel is presented in this work. By using existent fundamental reaction mechanisms and kinetic parameters, elementary reactions involved in an SOFC anode have been detailed, modeled and analyzed. This involves both homogeneous and heterogeneous chemistry, electrochemistry and surface diffusion. Modeling has been implemented in a patterned anode geometry with a C++ code using the open-source code CANTERA for chemical kinetics. The use of the patterned anode approach removes the mass transport complications and allows comparison with pre-existent experimental data. The model provides both the polarization curves and the surface coverage distribution and allows a high level of detail on the physical phenomena involved. In particular, understanding of how the competitive reactions behave is achieved. Results show a good agreement with the experimental conclusions provided previously by Sukesini et al., where concentrations on the fuel stream up to 75% CO behave similarly to those with pure H2 . Further analysis has been performed as well to understand both temperature and composition effects on the cell performance. CO has shown to stabilize the OCV response to temperature, improving the H2 response to such effect. At the same time, high temperatures have proven to improve the CO tolerance in the stream, providing good performance. Surface analysis shows that CO occupies most of the active sites present in the electrode, although it does not penalize the cell performance as far as there is some H2 in the stream. On the other hand, the presence of oxidized species (i.e., H2 O and CO2 ) in the anode compartment when the corresponding reductant species (i.e., H2 and CO) provokes a reversible reaction at the TPB vicinity, penalizing the performance of the cell.
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- Energy;Engineering, Chemical;Engineering, Mechanical