(453a) NiMo-Ceria-Zirconia Anode for Direct Gasoline-Fed Solid Oxide Fuel Cells

NiMo-ceria-zirconia
anode for direct gasoline-fed solid oxide fuel cells

Xiaoxue Hou^a,
Kai Zhao^a, Qusay Bkour^a, M. Grant Norton^b*, Su
Ha^a*

^aVoiland School of Chemical Engineering
and Bioengineering, Washington State University,
Pullman, WA, 99164, USA

^bSchool
of Mechanical and Materials Engineering, Washington
State University,
Pullman, WA, 99164, USA

* E-mail: suha@wsu.edu

To operate the Ni-based Solid Oxide Fuel Cells
(SOFCs) by feeding gasoline, the complex hydrocarbon needs to be reformed into
a simple synthesis gas (a mixture of hydrogen and carbon monoxide) for the
anode electrochemical oxidation reaction. In our previous research, a
NiMo-ceria-zirconia catalyst was found to show high reforming activity with a
coking resistance towards partial oxidation of model gasoline. When this
catalyst was applied as an internal reforming layer over the conventional
Ni-YSZ anode of SOFCs, the single cell displayed significantly improved initial
power density and performance stability under the direct isooctane/air mixture
feed condition. In addition to the high reforming activity, the
NiMo-ceria-zirconia can conduct both electrons and ions. Hence, the
NiMo-ceria-zirconia is expected to provide a dual-functionality for single
anode layer SOFCs: firstly to internally convert complex hydrocarbons into
synthesis gas with a high resistance to coking and secondly to
electrochemically oxidize the synthesis gas mixture for an electric power
generation.

Fig. 1 Schematic diagram
of SOFC single cell with the single layer anode.

In this work, we fabricated an
electrolyte-supported SOFC (shown in Fig. 1) using a NiMo-ceria-zirconia single
anode layer and investigated its performance under the direct isooctane/air
mixture feed condition. We found that the addition of Mo to the
Ni-ceria-zirconia significantly suppresses carbon deposition in the anode and
improves the lifetime of the single cell. Additionally, the presence of Mo in
the Ni-ceria-zirconia anode appears to facilitate a higher degree of sintering,
which increases the electronic conductivity and maximum power density of the
single cell. Consequently, at 800 degree C the single cell using 5 wt.% Mo in
the Ni-ceria-zirconia anode displayed a higher maximum power density of 212 mW
cm^-2 at 0.48V than the single cell using the Ni-YSZ anode without
the Mo promoter (49 mW cm^-2 at 0.48 V) under the isooctane/air
operation mode. Furthermore, the cell presented stable electrochemical
performance with a high coking resistance over 30 h operation using the model
gasoline. These promising results suggest the future application potential of
the NiMo-ceria-zirconia as single layer anode for SOFCs running on complex
hydrocarbon fuels.