As politicians and government officials debate how the modern world can reduce its dependence on oil, a carbon material recently discovered at the University of Missouri-Columbia could help to solve the problem. Physicist Peter Pfeifer believes this new material could position methane as the fuel of choice for the next generation of alternative fuel vehicles.

   While studying the internal structure of activated carbon -- a porous material commonly used in processes such as air filtration and water purification -- Pfeifer and his collaborators discovered the material they had created contained "carbon nanopores," a network of uniform channels that penetrated throughout the carbon. What makes this network unique is that it is fractal, a geometric pattern that is repeated at ever smaller scales.

   "Although they might seem complicated, fractals can be explained in relatively simple mathematical terms," said Pfeifer, whose findings are published in the March 18 issue of Physical Review Letters. "This discovery means we can predict how the carbon nanopores will act as a material, and we believe they have potential for a number of applications, the most promising of which is alternative fuel storage, particularly of methane gas."

   Currently, methane is stored in heavy-walled steel cylinders under extreme pressure -- more than 3,000 pounds per square inch (psi). If such a cylinder was used as a vehicle's fuel tank and there was an accident, the tank could explode like a bomb. Pfeifer said that if carbon nanopores were used, methane could be stored safely.

   "Our material offers a number of advantages for methane storage: It's lightweight, easy to manufacture in large quantities and relatively inexpensive," he said. "But most importantly, it would allow the methane to be stored at a safer, significantly lower pressure -- about 530 psi -- which reduces the risk of an explosion should a methane-powered vehicle be in an accident."

   By some estimates, there is a 10,000-year reserve of cleaner-burning methane gas on Earth that could be harnessed. Pfeifer believes that a commercially viable carbon nanopore storage product could be on the market within five years.