The path toward a viable renewable source of energy may be passing through Oxford.
Researchers in the laboratory of Miami University chemist Hong-Cai Zhou have discovered a breakthrough material that may make methane a more feasible form of alternative energy.
"The new material we made in the lab we can make easily and exceed (Department of Energy standards) for storage by a third," Zhou said. "This might give methane an advantage over other renewable fuels."
Zhou explained that one of the obstacles with methane as an alternative source of energy to gasoline for cars is the lack of safe and efficient means to store the methane.
Zhou's porous, sponge-like material recorded the highest known absorption rate-an important milestone on the way toward using methane to fuel automobiles.
Zhou said that methane is actually a higher quality fuel than standard gasoline. He noted that while regular unleaded gasoline has an octane level of 87, methane boasts a 130-octane level.
A higher octane level indicates how much fuel can be compressed before it spontaneously ignites. When gasoline ignites because of compression rather than a spark from a spark plug, this can cause damage to the engine. With its higher octane level, methane can compress more fuel than gasoline without damaging the car's engine.
According to Zhou, one of the major advantages of methane is its availability. He said methane can be found in natural gas fields, coalmines, corn or even manure.
Zhou said one of the basic problems his laboratory ran into during their research is methane's natural state.
"Methane is a gas instead of a liquid (like gasoline)," Zhou said. "(To convert the gas to a liquid), you need high pressure and low temperature (which is) a lot of energy consumed. It's not feasible because you have to liquefy it."
However this new material, called Porous Coordination Networks 14 (PCN-14), is able to retain methane in its gaseous state, eliminating the large amounts of energy needed to liquefy the gas.
Graduate student Shengqian Ma, one of the central researchers in the discovery, described the material as a "powder solid" and said the material is often called sponge-like because of the large amounts of methane that even a small piece can absorb.
Zhou also pointed out that the main component of methane is natural gas, which is used to heat most metropolitan homes, including ones in Oxford.
Zhou imagines a world in which existing gas lines can be connected to fill people's cars at their home, completely eliminating the need for gas stations.
While this breakthrough in methane storage is significant, Zhou's laboratory still has its sights on hydrogen storage and energy.
"Hydrogen is the ultimate clean energy," Zhou said. "The problem of (hydrogen) storage is an even bigger problem (than methane) … our ultimate goal is to find material to store hydrogen that is good enough for a hydrogen-fueled car."
Ma also has his sights set on that first element on the periodic table.
"Hydrogen, that's zero emissions," he said. "Plus hydrogen fueled cars are much more efficient than methane."
While methane is easily accessible from natural gas, Ma said separating hydrogen from water is an even more available, unlimited resource.
Despite the fact this breakthrough involves methane and not hydrogen, Zhou has aimed to use materials compatible with both methane and hydrogen from the get-go.
"This kind of sponge-like material should store hydrogen as well," he said. "In the past, (scientists would) work on one or the other, but we've found a lot of materials that are good for hydrogen and methane storage."
In total, Zhou has created 20 new materials during this project over the course of the last two years. While the other 19 materials have been able to store varying amounts of methane, PCN-14 has exceeded the rest.
While the hydrogen storage remains a work in progress, Zhou said methane is a good source to diversify the United States' energy profile and the next step lies in developing this new technology.
"Engineers will play a larger part in the next stage," Zhou said. "The material is still expensive. We need to develop it into something everyone can use."
So far there are several entrepreneurs in California interested in developing PCN-14. Zhou said that just like most new technology, the cost of the breakthrough would come down to an affordable price after more development.
