Sunday, November 17, 2013

Nanosized silicon leads to faster hydrogen production

Using hydrogen as a fuel has enormous future potential but in order to fully develop this potential science and technology will have to develop new methods of hydrogen production, the ones with the acceptable costs and efficiency. The researchers at the University at Buffalo have been lately working on various experiments and have discovered that super-small particles of silicon react with water to produce hydrogen almost instantaneously. In a series of experiments, the scientists created tiny spherical silicon particles about 10 nano-meters in diameter. Afterwards they have combined these particles with water, and the end result was the formation of silica acid (a nontoxic byproduct) and hydrogen.

There were many benefits of using this method: the chemical reaction didn't require any light, heat or electricity, and also created hydrogen about 150 times faster than similar reactions using silicon particles 100 nano-meters wide, and 1,000 times faster than bulk silicon. Also, the scientists were able to verify that hydrogen created by this method was relatively pure by testing it successfully in a small fuel cell that powered a fan. Splitting water to produce hydrogen is well known method, but these experiments proved that nano-sized silicon may be better solution to this than more obvious choices that people have studied for a while, such as aluminum.
Nano-sized silicon particles react with water to quickly produce hydrogen, according to new UB research.
The researchers hope that with the further development, this technology could form the basis of a 'just add water' approach and be able to generate hydrogen on demand which would be highly practical application for portable energy sources.

The detailed testing showed that the speed at which the 10-nano meter particles reacted with water was amazing. In under a minute, these particles created more hydrogen than the 100 nano-meter particles yielded in about 45 minutes. The maximum reaction rate for the 10-nano-meter particles was about 150 times as fast.

The explanation for such speed is that „once these particles start to react, the larger particles form non-spherical structures whose surfaces react with water less readily and less uniformly than the surfaces of the smaller, spherical particles.“

The major downside is that this technology still requires significant energy and other resources to produce the super-small silicon balls, but nonetheless these particles could help power portable devices in situations where water is available and portability is more important than low cost (for instance in different military operations).

This was the first study that shows how quickly we could generate hydrogen from silicon. Hydrogen is thought by many to be an excellent future energy option because of its abundance but the safe storage of produced hydrogen still remains a big issue.

As Dr. Swihart interestingly described "perhaps instead of taking a gasoline or diesel generator and fuel tanks or large battery packs with me to the campsite (civilian or military) where water is available, I take a hydrogen fuel cell (much smaller and lighter than the generator) and some plastic cartridges of silicon nano-powder mixed with an activator. Then I can power my satellite radio and telephone, GPS, laptop, lighting, etc. If I time things right, I might even be able to use the excess heat generated from the reaction to warm up some water and make tea."

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