NASA Tech Briefs: What is the background to the automotive catalyst project? Dr. Jeffrey Jordan: Back in the 1990s a group here was tasked to develop a low temperature oxygen catalyst (LTOC) that could operate in the cold vacuum of space to convert carbon monoxide [CO] to carbon dioxide [CO2]. The CO2 is the lasing medium, and as the current is passed through the CO2, some of that lasing gas is broken down into CO and oxygen [O2]. NASA needed a way to re-use the CO, and recombine it with the O2. At some point CO2 lasers went out, and lighter solid-state ones came in. And although the name low temperature oxygen catalyst stayed, it's actually a misnomer for the automobile implementation. That one is a three-way catalyst: it doesn't just oxidize CO, it also oxidizes hydrocarbons, and it reduces nitrogen emissions [NOx]. NTB: How did the re-purposing of the CO2 LTOC happen? Jordan: Well, we didn't just put it on a shelf. The group continued to work on it, knowing full well that a catalyst that could operate at ambient temperature had applications for indoor-air remediation -- replacing filters, say in heating, ventilation, and air-conditioning [HVAC] systems, or removing CO from indoor or air vehicles, or formaldehyde from industrial processes. In 1997, the group was contacted by Airflow Catalyst Systems, in Rochester, NY. That's when the work on making it a three-way catalyst really got going. NTB: What technologies are unique in the new converter? Jordan: The tin oxide in the new converter can be thought of as an active material, because it actually binds and releases O2, which is important when the vehicle is operating outside of ideal conditions. When you stomp on the gas, you're running rich -- you're not efficiently combusting. You've got tons of hydrocarbons, but not enough O2 to deal with them. But say you're going down a hill without touching the gas. At those times, there are no hydrocarbons but huge amounts of O2, which the tin oxide captures for use when the car is running rich. NTB: What other work is done at the Advanced Measurement and Diagnostics Branch? Jordan: Our entire branch, which has about 40 people, does work ranging from optical diagnostics, including things like pressure-sensitive paint, to development of nanoscale systems. Pressure-sensitive paint is an optical coating with embedded oxygen molecules that luminesce with varying intensities depending on the pressure. Using it we can measure pressure simply in a global way across the entire surface of an airplane or aerospace vehicle -- as opposed to building a model with tubing and surface-mounted pressure transducers. We're also focusing on single-wall carbon-nanotube-based devices -- materials on the order of one nanometer in diameter, with predictive strengths 1,000 times that of steel with a thousandth of the mass, and electrical properties ranging from insulating all the way to semiconducting. We're developing methodologies for the deposition and alignment of these types of structures to build what are called multifunctional materials, which might become the skin of revolutionary aerospace vehicles. We envision "lick-and-stick" types of sensors, where the nanolithography is applied onto a thin film or a membrane. NTB: How do you work with small businesses? Jordan: We can put in requests for proposals every year, for developmental and commercialization activities, to transfer our technologies. And that's how I've been able, in part, to pay the bills and keep the catalyst work going. These are technology pulls. The technology is being pulled from the commercial sector, where the companies can either sign a cooperative development contract, or straight-out license the technology and walk away. The automotive catalyst project is a great example because it has such huge potential. Resources:
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