Bioenergy

Researchers Extract Hydrogen Using ‘Defective’ Nanostructures

A team of scientists and students at North Carolina State University (NCSU) recently found that they were able to cut the energy consumption in half when using “defective” carbon nanotubes to extract hydrogen from water.

Current hydrogen production methods require heating water molecules to 2,000 degrees Celsius, but with more research, this nanoscale method could lower production costs, bringing hydrogen closer to becoming an alternative fuel for industry. The researchers, operating on the knowledge that a water molecule interacts with a carbon nanostructure, discovered that “defective” carbon nanotubes make it easier to “break” water molecules and extract hydrogen. Their published results, “Dissociation of Water on Defective Carbon Substrates” in Physical Review Letters (Sept. 30), reveal that naturally occurring defects in the nanotubes increase the rate of a chemical reaction because the atoms that form the defective nanotubes are “incomplete,” making them more reactive. “We studied water for many months and ran many different calculations, and we ended up showing that if you want to break a water molecule, you spend a lot less energy if you do it on this defective carbon material than if you do it by simply heating the molecule until it breaks,” said Marco Buongiorno-Nardelli, professor at NCSU’s Department of Physics. “You can reduce the energy necessary by a factor of two — you can do it at less than 1,000 degrees.” The team hopes to collaborate with other scientists to design and construct a nanoscale chemical reactor that will one day lead to a cost- and energy-efficient way to produce hydrogen. However, to make this dissociation reaction a viable process for hydrogen production there are still problems to solve before a truly catalytic process can be devised. “We think that nanotechnology can be used to produce more and better energy in an environmentally friendly way,” says Buongiorno-Nardelli. “Our experience with the water molecules so far leads me to believe we’re headed in the right direction.”