(490f) Molybdenum Dioxide (MoO2)-Based Anode Fabrication and Its Performance Analysis for SOFC Applications | AIChE

(490f) Molybdenum Dioxide (MoO2)-Based Anode Fabrication and Its Performance Analysis for SOFC Applications



Molybdenum Dioxide
(MoO2)-Based Anode Fabrication and Its Performance Analysis for SOFC
Applications

 

Byeong Wan
Kwona, Oscar Marin-Floresa, Shouzhen Hua,
M.
Grant Nortonb, Su Haa

 

a The Gene and Linda Voiland
School of Chemical Engineering and Bioengineering, Washington State University,
Pullman, WA 99164

bSchool of
Mechanical and Materials Engineering, Washington State University Pullman, WA,
99164-2920

Solid oxide fuel cells (SOFCs) are a
promising fuel flexible technology for clean and efficient conversion of
chemical energy into electrical energy. In SOFCs using hydrocarbons as fuel, hydrocarbons are oxidized on the surface of the Ni-based anode through a
pathway that produces carbon deposits known as coking. These carbon deposits deactivate the anode and lead to a poor
long-term stability of SOFC. Therefore, a new anode
material is required for direct liquid SOFCs having a good coking resistance
for a long-term stability.

Our
group conducted the fabrication and performance of a porous molybdenum dioxide
(MoO2)-based anode for direct utilization of liquid
fuel SOFCs instead of Ni-based anode, which can directly convert liquid fuels
into electrical energy without external fuel processors. The MoO2-based
anode was manufactured onto yttria-stabilized zirconia (YSZ) electrolyte with
Sr-doped LaMnO3 (LSM) cathode via combined electrostatic spray
deposition (ESD) and direct painting methods. The cell performance was measured
by directly feeding n-dodecane, which is a model compound of jet A fuel,
to the MoO2-based anode at 750oC. The stabilized power
densities from our MoO2-based SOFC were 2000 mW/cm2 at
0.6V using n-dodecane as fuels. To test the long-term stability of MoO2-based
SOFC against coking, n-dodecane was continuously fed into the cell for
24 h at its open cell potential of ~0.86V. During this long-term testing, voltage-current
density plots were periodically obtained and they showed no significant changes
over 24 hr. The X-ray diffraction patterns obtained from the spent MoO2-based
anode after 24 hr of operation indicated that the bulk structure of the MoO2-based
anode exhibit no phase transition. Based on our visual observations, there was
no coking. Therefore, the catalytic activity toward the
electrochemical oxidation of fuel remains stable even after 24hr operation. On
the other hand, SOFCs with conventional nickel (Ni)-based anodes under the same
operating conditions showed a significant amount of coke formation on the Ni
surface, which led to a rapid drop in cell performance. Hence, the present work
demonstrates that MoO2-based anodes exhibit an outstanding tolerance
to coke formation and the power density of the MoO2 anode is much
higher than that obtained with the Ni based anode.

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See more of this Session: Fuel Cell Technology

See more of this Group/Topical: Fuels and Petrochemicals Division