Computational study of Ni-CGO as a solid oxide fuel cell anode
File(s)
Author(s)
Chen, Xihao
Type
Thesis
Abstract
In this thesis, two computational works are presented to address the identified gap in two key operational reactions in SOFCs: partial methane oxidation (POM) and electro-oxidation of hydrogen (HOR). The model for both works are constructed based on intrinsic kinetics and provide a detailed description of physical and electrochemical phenomena occurring in the composite. In the POM study, a quasi 2D reactive-diffusion model is employed to reveal the main mechanism causing the unique profile of CO observed in transient experiments. Through mechanism analysis, a dynamic equilibrium of oxygen concentration established by oxygen bulk diffusion and spill-over effect was found to be the primary factor. A sensitivity study of the processes involved also suggests the presence of co-limiting mechanisms of these diffusive fluxes in the release of CO. Furthermore, the model has shown its capability to estimate the catalyst intrinsic properties by fitting parameters.
On the other hand, the HOR study was conducted to identify the role of Nickel in HOR catalysis on the Ni-CGO surface. The constructed model provides a comprehensive description of the processes occurreing in the electrode including charge transport, electrochemical reaction and mass transfer in the gas phase. The resultant model is capable of reproducing EIS data of two different composites: pure CGO and an impregnated Ni-CGO electrode. Followed by a process analysis, a hypothesis regarding to Nickel’s role was identified. Nickel could not only act as electron conductor, but also as an active surface facilitating reactant adsorption. Further study to validate this hypothesis is proposed in the conclusion section
On the other hand, the HOR study was conducted to identify the role of Nickel in HOR catalysis on the Ni-CGO surface. The constructed model provides a comprehensive description of the processes occurreing in the electrode including charge transport, electrochemical reaction and mass transfer in the gas phase. The resultant model is capable of reproducing EIS data of two different composites: pure CGO and an impregnated Ni-CGO electrode. Followed by a process analysis, a hypothesis regarding to Nickel’s role was identified. Nickel could not only act as electron conductor, but also as an active surface facilitating reactant adsorption. Further study to validate this hypothesis is proposed in the conclusion section
Version
Open Access
Date Issued
2024-04-06
Date Awarded
01/09/2024
License URL
Advisor
Brandon, Nigel
Banerjee, Aayan
Publisher Department
Earth Science & Engineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)