Silicon powder produces hydrogen on demand

Posted by Kate Taylor

Super-small particles of silicon react with water to produce hydrogen almost instantaneously, University at Buffalo researchers have discovered.

It means that soldiers or campers, for example, need only take a small hygrogen fuel cell and a bag of the powder to power electronics and other devices on the move.

"It was previously unknown that we could generate hydrogen this rapidly from silicon, one of Earth’s most abundant elements," says research assistant professor Folarin Erogbogbo.

"Safe storage of hydrogen has been a difficult problem, even though hydrogen is an excellent candidate for alternative energy, and one of the practical applications of our work would be supplying hydrogen for fuel cell power. It could be military vehicles or other portable applications that are near water."

Spherical silicon particles about 10 nanometers in diameter combine with water and react to form silicic acid - which is non-toxic - and hydrogen, a potential source of energy for fuel cells.

The reaction doesn't require any light, heat or electricity - and also creates hydrogen about 150 times faster than similar reactions using silicon particles 100 nanometers wide, and 1,000 times faster than bulk silicon.

The reason's down to to geometry. As they react, the larger particles form nonspherical structures whose surfaces react with water less readily and less uniformly than the surfaces of the smaller, spherical particles.

Though it does take significant energy and resources to produce the powder, the particles could help power portable devices in situations where water is available and portability is more important than low cost.

"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 nanopowder mixed with an activator," says Professor Mark Swihart.

"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 excess heat generated from the reaction to warm up some water and make tea."