Alternative Energy

Environmentalists, common man, scientists, politicians, everyone want to breathe fresh and clean air and leave this earth in a better shape for next generation. Environmentalists and scientists are working to make this planet a better place to live. Hydrogen driven vehicles are a small step towards that goal. But the main hurdle to produce hydrogen vehicles on a mass scale is that they can’t store much fuel. Researchers at the University of Michigan, Ann Arbor and Arizona State University have developed a sponge-like material, a new metal-organic framework that has a record breaking surface area. This kind of material can be very useful for many industrial applications such as catalysis, separation, and gas storage.

Adam Matzger who is an associate professor of chemistry in the University of Michigan, led the team and published their work online in a paper on March 6 in the Journal of the American Chemical Society. Matzger said about the surface area, “Surface area is an important, intrinsic property that can affect the behavior of materials in processes ranging from the activity of catalysts to water detoxification to purification of hydrocarbons.”

Researchers were working on this aspect for a long time. A few years ago, the upper limit for surface area of porous materials was around 3,000 square meters per gram. In the year 2004, a U-M team that included Matzger also developed a material known as MOF-177 that set a new record. MOF-177 created a new category of materials called as metal-organic frameworks. Metal-organic frameworks are scaffold-like structures which are made up of metal hubs linked together with struts composed of organic compounds. It is amazing that just one gram of MOF-177 has the surface area of a football field.

Matzger shared his views, “Pushing beyond that point has been difficult.” But he and his team continue to work on the same line and achieved the feat with the new material known as UMCM-2 (University of Michigan Crystalline Material-2). UMCM-2 has a record-breaking surface area of more than 5,000 square meters per gram!

To create UMCM-2 the researchers employed a technique called coordination copolymerization. They applied the same technique to create UMCM-1. UMCM-1was made up of six, microporous cage-like structures surrounding a large, hexagonal channel. This time they used a slightly different combination of ingredients and the result is UMCM-2. UMCM-2 is composed of fused cages of various sizes and does not have the channel found in UMCM-1. Matzger said about the new material, “The new structure is a bit surprising and shows how the coordination copolymerization method has real potential for new materials discovery.”

This development may help speed the production of ultra-clean fuel cell vehicles powered by hydrogen. If we talk in a layman’s term then we can say that just 1/30th of an ounce of the sponge-like nanomaterial has the approximate surface area of a football field. This sponge-like nanomaterial may meet the hydrogen storage goals proposed by the U.S. Department of Energy (DOE) for hydrogen fuel cell vehicles.

This sponge-like nonomaterial or UMCM-2 consists of zinc oxide nanoclusters. Each zinc oxide nanocluster is about 1/50,000 the width of a human hair. These zinc oxide nanoclusters are linked together by organic materials to produce a robust porous framework. Now what Matzger thinks about future? He explained, “More and more attention, both by the team at Michigan and in industry will be focused on moving applications forward in areas such as hydrogen storage and large molecule separations.”