(1) Surface electrochemistry of oxygen reduction and formic acid oxidation

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 sensor for peroxide explosives

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) Electrochemistry of graphene materials

Beside fabrication techniques and device design, one of the most important pillars in the microchemical systems is materials that constitute the microchemical systems. Recently, a very interesting carbon material, named graphene, is reported. The graphene can be grown as an ultrathin graphite layer grown on a single-crystal silicon carbide by thermal decomposition. This novel material is compatible with the conventional microfabrication techniques and has the electronic property similar to that of the carbon nanotube. While initial research activities were mainly on solid-state electronic properties of the epitaxial graphene, chemical and electrochemical aspects of the epitaxial graphene are rarely studied. On the other hand, it is well known that metallic or semiconductor nanowires can be fabricated onto a graphite surface by an edge-decoration electrodeposition. The edge decoration, combined with lithography, can be used to fabricate metallic and semiconducting nanostructures of custom shape and size.