(1) Surface electrochemistry of oxygen reduction Several underpotential deposits (UPD) show electrocatalytic activity for oxygen reduction. Bi, Tl, and Pb UPD on Au(111) were studied with surface science tools in order to verify structure-function relation. Proposed mechanism involves a bimetallic interaction between the adsorbed oxygen molecule and the catalyst surface.

(2) Microfabricated electrochemical sensor for toxic vapor Electrochemical sensor for toxic vapors, such as organophosphate and hydrogen cyanide, is developed. In order to build a fast and sensitive sensor, critical aspects include fabrication of high-area gas-liquid interface, thin-electrolyte cell, and the sensing electrodes with low detection limit.

For the future research, I propose to work on the following problems:

(1) Electrochemical systems with nanoscale and biological materials Electrochemistry can play a unique and significant role in microfabricated systems. Compared to optical transducer, fabrication and measurement of electrochemical transducer is much simpler and cheaper. Also, copper electrodeposition for high-speed Cu/low-k interconnect is a representative example of electrochemistry contribution to microfabrication. Future research opportunities and challenges include electrochemical fabrication and application of nanowires, fabrication of MEMS-compatible reference electrode, and incorporation of enzymes or other biomaterials into electrochemical sensors and energy sources.

(2) Development of Novel Electrocatalyst for Renewable Energy Systems Fuel cell is one of the most promising renewable energy systems, in which both the oxygen reduction on cathode and the fuel oxidation on anode require the precious and expensive catalyst materials. A significant volume of research has been done to find a better and cheaper catalyst material but still development of cheaper catalyst with better performance is required. One of the methodologies is the combinatorial approach for high-performance electrocatalyst with bimetallic or trimetallic composition. Important aspects of combinatorial approach include microfabrication of array electrode patterns, tools to deposit different compositions of catalyst material, multiplexer-potentiostat circuitry.