An article published in a paper in the Nano Letters journal has described the use of nanowires to provide significant increase in both longevity and efficiency of fuel cells. These long platinum nanowires have been developed at the University of Rochester and could improve fuel cells into a commercially viable solution.“People have been working on developing fuel cells for decades. But the technology is still not being commercialized,” says James C. M. Li, professor of mechanical engineering at the University of Rochester. “Platinum is expensive, and the standard approach for using it in fuel cells is far from ideal. These nanowires are a key step toward better solutions.”
Nanowire fuel cells will probably change our future, diminished our need of petroleum for transportation purposes and decrease pollution.
James C. M. Li and one of his graduated student Jianglan Shui, produced platinum nanowires of ten nanometers in diameter and a few centimeters in length. This length allowed them to create a self-supporting “web” of pure platinum. The “web” can then serve as an electrode in a fuel cell.
The thing was to produce longer nanowires that could make free-standing fuel cell catalysts. Much shorter nanowires have already been used in fabrication of nanocomputers and nanoscale sensors. But longer, ultra-thin solid fiber nanowires require a process known as electro-spinning. This process was applied by the two scientists for the development of the platinum nanowires. Platinum nanowires are thousands of times longer than any previous wires design before.
The catalyst is the one that facilitates the reaction of hydrogen and oxygen. Platinum was used since the beginning as catalyst because of the harsh acidic environment inside a fuel cell. Platinum has as well an increased energy efficiency than most other metals.
Li concentrated at first his efforts of developing the catalyst on platinum nanoparticles. The idea was very simple: the greater the surface is, the greater the efficiency will be. But Li had two major problems both linked to the high cost of platinum so the platinum nanoparticels principle was put aside and the nanowires took their place.
“The reason people have not come to nanowires before is that it’s very hard to make them.The parameters affecting the morphology of the wires are complex. And when they are not sufficiently long, they behave the same as nanoparticles” said James C. M. Li.
An important challenge was to overcome the formation of platinum beads along nanowires. Improvements are still made to reduce bead formations and after the final work is done, Li says that he wants to build a fuel cell and demonstrate this technology is very efficient.