research & development

Nisshinbo Creates Platinum-Free Carbon Catalyst

Nisshinbo Industries Inc. has worked with the Tokyo Institute of Technology to develop the technology to use carbon instead of expensive platinum as the electrode catalyst for fuel cells. The company hopes to have a practical version of the new catalyst ready in 2009, and will start by commercializing a product for the electrodes of residential fuel cells. Later, it will develop and commercialize a version for automotive fuel cells.

Platinum is now used as the catalyst, but high demand and unstable supplies from main producer South Africa have driven prices high. A 1kW-class residential fuel cell uses several grams of platinum and a 150kW-class automotive fuel cell uses around 60gm, which currently adds $3,762 to the cost of a car. The carbon catalyst promises to remove this cost barrier which, along with the needed infrastructure for hydrogen filling stations, is a major roadblock to the adoption of fuel cells for homes and cars.

The new catalyst is made from nanospheres of carbon. As a fuel cell catalyst, 10 times more carbon is required than platinum; but even in this larger volume, the cost is just a tenth that of using platinum.

Porous Nanostructures for Fuel Cells and Microchips

Cornell researchers have developed a method to self-assemble metals into complex nanostructures. Applications include making more efficient and cheaper catalysts for fuel cells and industrial processes and creating microstructured surfaces to make new types of conductors that would carry more information across microchips than conventional wires do.

The method involves coating metal nanoparticles ‚ about 2nm in diameter ‚ with an organic material known as a ligand that allows the particles to be dissolved in a liquid, then mixed with a block co-polymer. When the polymer and ligand are removed, the metal particles fuse into a solid metal structure.

"The polymer community has tried to do this for 20 years," said Ulrich Wiesner, Cornell professor of materials science and engineering. "But metals have a tendency to cluster into uncontrolled structures. The new thing we have added is the ligand, which creates high solubility in an organic solvent and allows the particles to flow even at high density."

Another key factor, he added, is to make the layer of ligand surrounding each particle relatively thin, so that the volume of metal in the final structure is large enough to hold its shape when the organic materials are removed.

Hydrogen Without the Carbon Footprint

A greener, less expensive method to produce hydrogen for fuel may eventually be possible with the help of water, solar energy and nanotube diodes that use the entire spectrum of the sun's energy, according to Penn State researchers.

"Other researchers have developed ways to produce hydrogen with mind-boggling efficiency, but their approaches are very high cost," says Craig A. Grimes, professor of electrical engineering. "We are working toward something that is cost effective."

Currently, the steam reforming of natural gas produces most of our hydrogen. As a fuel source, this produces two problems. The process uses natural gas and so does not reduce reliance on fossil fuels; and, because one byproduct is carbon dioxide, the process contributes to the carbon dioxide in the atmosphere, the carbon footprint.

Grimes and his team produce hydrogen from solar energy, using two different groups of nanotubes in a photoelectrochemical diode. They report in the July issue of Nano Letters that using incident sunlight, "such photocorrosion-stable diodes generate a photocurrent of approximately 0.25 milliampere per centimeter square, at a photoconversion efficiency of 0.30%."

"It seems that nanotube geometry is the best geometry for production of hydrogen from photolysis of water," says Grimes.