Fuel Cells
Fuel cells are one of the hottest latest research topics these days. They could become one of the technologies that will throttle us to the next age of mankind, namely that of the sustainable one and that which is kinder to the environment.
The PEM fuel cell was developed at General Electric in the 1960s. They have been used in some space shuttle programs and currently is being researched to use in cars, batteries etc.
They have an advantage of producing very clean byproduct, namely water. Operating on low temperatures, they are easy to start up and need only hydrogen and oxygen to operate. The main difficulty lies on the production and mobility of hydrogen, which being the lightest gas, has a large amount of kinetic energy.
PEM fuel cells are made up of namely three layers pressed together called the membrane electrode assembly (MEA). The first layer are the electrodes. The second being a polymer membrane, made of Nafion and the third is another electrode. There is a thin platinum catalyst between the Nafion and the electrodes. Thats what I am going to talk about here.
The electrodes are mainly made up of various types of carbon paper with platinum spray painted on them. So therefore, I was wondering there must be a group out there somewhere spraying platinum on carbon nanotube electrodes! Yan Labs of the University of California: Riverside churns out a lot of papers on all kinds of fuel cell research (go to publications, search for “waje”).
Spraying carbon nanotubes on PEM electrodes increases the utilization of platinum. Some of the platinum is always left out of the electrode circuit or inefficient contact with gas and reduces efficiency. This paper electro-deposited (non-ink) carbon nanotubes on carbon paper. It promised a fuel cell which would work much more efficiently than the previous conventional carbon papers. Then continued research showed a 58% vs 38% increase in Pt utilization and higher performance was observed. The group further went on the achieve better Pt utilization by sulfonizing CNTs which assisted in platinum deposition uniformity. They deposited smaller Pt particles of the 2-2.5 nm range. Performance was reported to be higher than conventional electrodes. One of their last papers published on the PEM is on the durability of it, such as corrosion resistance and MWNTs exhibiting less surface area loss without compromisig catalysis.
Carbon nanotubes hold much promise everywhere. It seems that for every lab experiment I do, I should search for a CNT substitution material on the parts of the equipment. The only problem we face now is to growing them industrially and commercially, which I am sure will happen very soon…
PS : There are many more papers on the Yan site which also talks about other fuel cells.
