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Fuel cell, nanoscale materials, molecular electronics and surface chemistry
Research in my group focuses on four areas: electrocatalysis with an emphasis on direct methanol fuel cells, surface chemistry, nanoscale materials, and molecular electronics.
In electrocatalysis, we use uniform arrays of Pt and Pt-based alloy nanoparticles as model catalysts to study particle structural effects on methanol oxidation and oxygen reduction. These particle arrays are well separated, free of surface molecular protecting layer, and uniform in size. Exploiting their uniform distribution, we are also interested in using particle arrays made of other metals as catalysts/templates for growing nanotubes and nanowires, which have broad applications in many areas including bioanalysis, sensors and electronic devices. These nanoscale structures are characterized by transmission electron microscope (TEM) and scanning electron microscope (SEM).
To understand the adsorption and reactions on metal electrode surfaces, we use surface infrared spectroscopy and surface-enhanced Raman spectroscopy (SERS). In the surface spectroscopic research, we are also working on developing a new technique that combines Raman spectroscopy and scanning tunneling microscope (STM). This new technique will be able to image the surface and obtain chemical information from the same nanoscopic spot simultaneously. Applications of this new tool include study the chemical bond formation on a surface, surface local reactivity and structure, etc.
In the molecular electronics research, in collaboration with Professors Zhou and Yarrison-Rice (Physics Department), 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 heavily involves organic/inorganic synthesis as well as nanofabrication and characterization.
Selected References
“Electrooxidation of Carbon Monoxide on Gold Nanoparticle Ensemble Electrodes: Effects of Particle Coverage”, S. Kumar, S. Zou, J. Phys. Chem. B, 2005, 109, 15707.
“Electrochemical and Surface-enhanced Raman Spectroscopy Investigation of CO and SCN- Adsorbed on Aucore-Ptshell Nanoparticles Supported on GC Electrodes”, B. Zhang, Q.-L. Zhong, B. Ren, Z.-Q. Tian, S. Zou, Langmuir, 2005, 21, 7449.
“Coupled surface-enhanced Raman spectroscopy and electrical conductivity study of 1, 4-phenylene diisocyanide in molecular electronic junctions”, A. Jaiswal, K. Tavakoli, S. Zou, Anal. Chem., 2006, 78, 120.
“Surface-enhanced Raman spectroscopy studies of 1,4-phenylene diisocyanide adsorption on Au and Pt-group transition metals”, S. Gruenbaum, M. Henney, S. Kumar, S. Zou, J. Phys. Chem. B, 2006, in press.
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