Release Date: April 29, 2014
NETL’s Nanometer-Sized Heaters Use Sunlight to Convert CO2
Conversion Into Usable Gases Combats Climate Change, Lowers Cost of Carbon Capture
A team of scientists from the U.S. Department of Energy’s National Energy Technology Laboratory and West Virginia University has developed new nano-sized materials capable of converting visible light into thermal energy, which can then be used to drive the conversion of carbon dioxide (CO2) to methane, carbon monoxide, and other usable gases.
Conversion of CO2 into these valuable intermediates, which can be used in the manufacture of products such as fuels, plastics, and chemicals, will help offset the cost of deploying technologies to capture the greenhouse gas. Efficient management of CO2 will allow for the continued use of America’s abundant fossil energy resources while mitigating the climate impacts associated with carbon emissions.
The electron micrograph on the left shows nanometer-sized plasmonic heaters (red arrows) dispersed on a zinc oxide catalyst. This system is shown schematically to the right of the micrograph.
The team research has developed several catalyst systems that rely on nano-sized particles—the only size particles that can absorb visible light. The systems use gold (Au) nanoparticles and other materials as the heater, and zinc oxide (ZnO) nanoparticles as the catalytically active substrate. Upon exposure to light, free electrons on the surface of the metal become excited, transforming the optical energy into heat. Experimental results show that low-intensity visible light can heat the Au-ZnO catalysts up to approximately 600 degrees Celsius, and the light intensity dictates which gas product will result.
The new catalysts are robust and remain active after repeated light exposure and cycling, reducing CO2-conversion cost. Use of natural sunlight for this process improves efficiency and reduces the cost of using CO2. The results of this work are described in an article appearing in the international journal Nanoscale published by the Royal Society of Chemistry (Nanoscale, 5, 6968, 2013). An NETL video describing CO2 conversion by nanoheaters can be viewed here.
This month, NETL and many other of the Energy Department’s national labs are showcasing their contributions to "The Science of the Very Fast and Very Small.” For more information, please visit the Energy Department’s national lab webpage.