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"We are interested in exploring factors
governing the performance of fuel cell catalysts. Uniform arrays of
metal nanoparticles are used as model
catalysts to study particle structural effects on methanol
oxidation and oxygen reduction. To understand the adsorption and
reactions on catalyst surfaces, we use surface infrared
spectroscopy and surface-enhanced Raman spectroscopy (SERS)."
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The objective for our fuel cell research is to
reveal factors governing the electrocatalytic
activities of the electrocatalysts by using
nanoparticle arrays and surface vibrational spectroscopies.
Uniform arrays of Pt and Pt-based alloy nanoparticles
are used as model catalysts to study particle structural effects on
methanol oxidation and oxygen reduction, which are of importance to
methanol fuel cell. These particle arrays are well separated, free of
surface molecular protecting layer, and uniform in size, therefore
are excellent model systems (see Figure for an example). To
understand the adsorption and reactions on catalyst surfaces, we use
surface infrared spectroscopy and surface-enhanced Raman spectroscopy
(SERS). SERS in particular provides unprecedented information
regarding the catalyst oxidation state and the molecule-catalyst
bonding. The fundamental understandings gained from this study will
guide the search of new catalyst materials.
In the molecular electronics research, in collaboration with Professors
Zhou (Chemistry and Biochemistry) and Yarrison-Rice
(Physics), we are using novel inorganic complexes containing two
metal centers as molecular diodes and transistors. The unique
molecular electronic properties come from the difference in the electron
affinity of the metal centers and the possibility of forming multiple
metal-metal bonds between the two metal atoms. The conductivity
measurements are conducted using electrode pairs with a nanometer
scale gap, where the molecular being tested will be located. This
project may yield a new set of molecules for electronic devices and
will provide fundamental knowledge about the underlying mechanisms
dictating electron transport properties of molecules.
Undergraduate researcher's roles in your lab
Undergraduate researchers in our lab will be
involved directly in the research projects that are part of our
efforts described above. The projects are tailored towards the
undergraduate students so that it is challenging enough yet not too
overwhelming. There are several publications involving undergraduate
coauthors.
Graduate student's role in your lab
Graduate students will be engaged in the research
activities described above. In general, students will gain hands-on
experience on electron microscopies, scanning
probe microscopies, nanomaterial
fabrication and catalytic activity measurements of fuel cell
catalysts.
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Presentations
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Funding
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GM “Fuel
Cell Research” $106,000.
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Publications
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H. Yang, Y. Yang and S. Zou,
"Surface-enhanced Raman spectroscopic
evidence of methanol oxidation on Ru
electrodes", J. Phys. Chem. B, 2006, 110, 17296.
S. Kumar, S. Zou, "Electroreduction of
O2 on uniform arrays of Pt and PtCo nanoparticles", Electrochem.
Commu., 2006, 8, 1151.
S. Gruenbaum, M. Henney, S. Kumar, S. Zou,
"Surface-enhanced Raman spectroscopy
studies of 1,4-phenylene diisocyanide
adsorption on Au and Pt-group transition metals", J.
Phys. Chem. B, 2006, 110, 4782.
A. Jaiswal, K. Tavakoli, S. Zou, "Coupled surface-enhanced Raman spectroscopy
and electrical conductivity study of 1, 4-phenylene diisocyanide in molecular electronic
junctions", Anal. Chem., 2006, 78, 120.
S. Kumar and S. Zou, "Electrooxidation of
Carbon Monoxide on Gold Nanoparticle
Ensemble Electrodes - Effects of Particle Coverage", J.
Phys. Chem. B, 2005, 109, 15707.
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