Could nanocrystals be the next big fuel source?

As with most little things that don't behave as we expect them to, nanocrystals pose unique challenges. Take gold, for example. We recognize this particular metal for its signature golden color. If you were panning for gold, you would recognize even a small fleck of gold by its color. Reduce this fleck to a nanometer, though, and you will not be able to recognize it (even if you could see a nanocrystal). It will turn blue-green or red because the nanocrystals, since they are so small, are almost entirely surface area. This greater ratio of surface area allows the metal nanocrystals to absorb colors instead of reflecting them [source: Boysen].

While this little fact may impress your friends at parties, this knowledge -- that nanocrystals follow different rules than other matter -- could also impact the world's fuel sources. Not only can nanocrystals take on different qualities than larger particles of the same material, but they react differently with other elements. The smaller the particle, the more atoms it has at the surface; the more atoms at the surface, the greater the surface area and the greater the ability to interact with other elements.

Think about it like this: You're swimming in a cylinder of water that is deep but not wide. You can touch the edges of the cylinder by simply outstretching your arms and legs like a starfish. Then you decide to swim laps in a shallow pool the size of a basketball court. All things being equal, you'll come into contact with more of the water's surface area if you paddle around the shallow pool than float in the deep cylindrical one. That's how nanocrystals work, too. Their many small particles have more surfaces exposed to other chemicals or elements, which can lead to a greater rate of chemical reaction

This greater surface area makes nanocrystals good catalysts, or substances that enable chemical reactions. When used as catalysts, nanocrystals can increase the rate of a chemical reaction without undergoing changes themselves. This means nanocrystals can convert raw materials into fuel at lower temperatures than other catalysts might. Conversely, nanocrystals make it possible to burn more fuel at a lower temperature.

Nanotechnology could make existing alternative fuel technology more viable. For example, corn is converted into ethanol, an alternative non-fossil fuel. But by the time the corn germinates and is irrigated, harvested, transported and then converted into ethanol, the process is not particularly cost- or energy-efficient. By using nanocrystals as a catalyst, an army of enzymes could efficiently and quickly dine on waste materials like wood chips or grass and convert them to ethanol [source: Understanding Nano].

There's just one problem, though. Nanoparticles, while naturally occurring, are more difficult to purposefully manufacture. Researchers haven't quite figured out a way to harness nanoparticles, let alone mass-produce them. When they do, we could have a renewable, efficient and inexpensive power source -- one that could potentially result in lower energy bills and vehicles with greater engine mileage.

Turn on a flashlight and you're witnessing a fuel cell at work. At its most basic, a fuel cell is a power source that uses a chemical reaction to produce an electrical current. The battery inside the flashlight is a fuel cell that confines its chemicals into a tidy little package. Once the chemicals wear out and can no longer react with each other, the battery can be recharged or thrown away.

There is another type of fuel cell that relies on the intake of external elements. Instead of having all its elements enclosed, a hydrogen fuel cell, for example, needs access to peripheral elements like hydrogen and oxygen to produce electricity [source: CAFCP]. And this is where nanotechnology comes into play. The application of nanotechnology could make hydrogen fuel cells work more efficiently and make them less expensive to produce; this could result in lower prices for vehicles fueled by this type of alternative energy, as well as the production of fuel cells that require less energy to operate.

With nanocrystals in play, fuel cell manufacturing costs could also drop. Traditionally, hydrogen fuel cells use platinum as a catalyst to convert external elements into energy. Platinum is relatively rare and extracted through energy-intensive mining. By using platinum nanocrystals, it greatly reduces the amount of pricey platinum needed to make a fuel cell work. In some cases, nanocrystals of less-expensive materials like cobalt can be used to bypass the need for platinum altogether [source: Understanding Nano].

Nanocrystals could change the material used to construct fuel cells, too. Most fuel cells use liquid to connect electrodes because liquid is a better conductor than a solid material. But by infusing solid materials with nanocrystals, the materials themselves become more conducive, eliminating the need for a liquid conductor, which leads to saved space, increased conductivity and smaller fuel cells [source: Science Daily]. In the end, technology using some of the world's smallest particles could lead to the next big fuel source -- or at least a more efficient way to use the fuel sources we already have.