Fuel cells offer the promise of a clean energy source for stationary power generation. They produce energy from hydrogen, natural gas, alcohol, or other readily available hydrocarbon fuels. Fuel cells date back to the nineteenth century when Grove, in 1839, first published his work on the generation of electricity by partially immersing two platinum electrodes and separately supplying oxygen and hydrogen to them.1 There is considerable current interest in fuel cells as an environmentally clean alternative to fossil-fuel-burning power sources.
Catalysts for Fuels Cells

Platinum is the most common catalyst for fuel cells; however, due to its high cost it is often doped with palladium, ruthenium, cobalt/nitrogen complexes, or more recently iridium or osmium. In addition to its high cost, platinum is also quite rare. In fact, there is not enough platinum in the world to equip every vehicle in use today with a traditional (Pt-catalyst) proton exchange membrane (PEM) fuel cell. For this reason, new catalysts, doped-platinum catalysts, and new platinum-deposition techniques are all being developed to reduce the amount of platinum needed for fuel cell catalysts.
Conducting Polymers

The discovery over twenty five years ago of relatively high electrical conductivity (~103 S/cm) of doped polyacetylene sparked extensive research in the application of conjugated polymers in such diverse fields as electronics, energy storage, catalysis, chemical sensing, biochemistry, and corrosion control. Unfortunately, the conducting polymers were found to be unstable in air and difficult to process. Significant advances in improving the desired electrical, optical, and mechanical properties, while simultaneously enhancing processability and stability, have been realized by cross-disciplinary collaborations between chemists, physicists, materials scientists, and engineers.
Polyaniline

Polyaniline is becoming the conducting polymer of choice in many applications for several reasons: its electronic properties are readily customized; it exhibits excellent chemical stability, and is the least expensive of the conducting polymers.
Polythiophenes

Polythiophenes have been studied extensively for use in light emitting diodes, among other applications, due to the chemical variability offered by substitution at the 3- and 4- positions. The regularity of the side-chain incorporation strongly affects the electronic band gap of the conjugated main chain and is critical to device performance. Sigma-Aldrich offers highly regiocontrolled alkylsubstituted polythiophenes (P3AT): almost completely regioregular head-to-tail (HT) P3AT and regiorandom (1:1 HT/HH) P3AT.10