Houston (TX) – While developing tools to analyze non-consuming catalytic reactions in water, Rice University researchers have created a visible-light microscope that can actually view molecules breaking apart and re-bonding into new forms. This tool may help scientists create new catalysts which remove toxins and pollutants from water sources faster and with greater efficiency.
Rice University researcher Michael Wong describes the device, “We can see the vibrations of the bonds between the atoms of our molecules. By watching the way these vibrations change frequency and intensity with time, we can watch how molecules transform into other molecules step-by-step.”
The research utilizes nanoshells comprised of gold and silica. These were invented 10 years ago at Rice by Naomi Halas, called “a nanophotonics pioneer.” These nanoshells are about 20x smaller than red blood cells, and they amplify and focus light tight enough to create a visible view just a few molecules wide.
Trichloroethene (TCE) is a common solvent used today. It is also a carcinogen and one of the world’s most pervasive and troublesome groundwater pollutants, occurring in 60% of contaminated water sites – according to the press release.
A need to understand
A few years ago, Wong’s research group developed a catalyst capable of breaking down TCE into nontoxic components. Made of palladium and gold, the manufactured product broke down TCE faster and more efficiently than was predicted by their model. While no explanation was given for this extra speed, the hunt was on to find out why.
Over the next two years, the team developed the nanoshell microscope. Halas said, “Nanoshells are among the world’s most effective chemical sensors, and this study reveals another area where they are uniquely valuable. We are aware of no other method that provides this level of detail about metal-catalyzed chemical reactions that run in water. Given the overwhelming interest in biofuels processing and other water-based reactions, we expect this to be a very useful tool in understanding these chemistries in more detail.”
Research for Wong and associates is funded by Halliburton, Rice University, Oak Ridge Associated Universities, National Science Foundation, Kraft, Smalley Institute, 3M, Advanced Aromatics, Center for Biological and Environmental Nanotechnology (CBEN), The Welch Foundation and others.