One benefit of greater surface area and improved reactivity in nanostructured materials is that they have helped create better catalysts. As a result, catalysis by engineered nanostructured materials already impacts about one-third of the huge U.S. and global catalyst markets, affecting billions of dollars of revenue in the oil and chemical industries. An everyday example of catalysis is the catalytic converter in a car, which reduces the toxicity of the engine’s fumes. Nano-engineered batteries, fuel cells, and catalysts can potentially use enhanced reactivity at the nanoscale to produce cleaner, safer, and more affordable modes of producing and storing energy.
A simple thought experiment shows why nanoparticles have phenomenally high surface areas. A solid cube of a material 1 cm on a side has 6 square centimetres of surface area, about equal to one side of half a stick of gum. But if that volume of 1 cubic centimetre were filled with cubes 1 mm on a side, that would be 1,000 millimetre-sized cubes (10 x 10 x 10), each one of which has a surface area of 6 square millimetres, for a total surface area of 60 square centimetres; about the same as one side of two-thirds of a 3” x 5” note card. When the 1 cubic centimetre is filled with micrometre-sized cubes, a trillion (1012) of them, each with a surface area of 6 square micrometres, the total surface area amounts to 6 square meters, or about the area of the main bathroom in an average house. And when that single cubic centimetre of volume is filled with 1-nanometer-sized cubes, 1021 of them, each with an area of 6 square nanometres, their total surface area comes to 6,000 square meters. In other words, a single cubic centimetre of cubic nanoparticles has a total surface area one-third larger than a football field!
Large surface area also makes nanostructured membranes and materials ideal candidates for water treatment and desalination (e.g., see “Self-Assembled, Nanostructured Carbon for Energy Storage and Water Treatment” in our database, NNI Accomplishments Archive), among other uses. It also helps support “functionalization” of nanoscale material surfaces (adding particles for specific purposes), for applications ranging from drug delivery to clothing insulation.