The nanostructures constitute a new model system, a simplified version of a catalyst that would be used in an application. Such models reveal to chemists the exact structure and reaction mechanisms of metal oxides.
Developed by researchers from the Department of Energy's Pacific Northwest National Laboratory, the University of Texas-Austin and Washington State University, the discovery may offer a platform for fundamental reactivity studies of metal oxides used as catalysts in converting hydrocarbons into fuels and value-added chemicals.
"There is a striking difference between commercial catalysts and the new model system," said Mike White, the UT professor leading the PNNL Institute for Interfacial Catalysis. Variability in commercial catalyst size and chemical composition makes it difficult to accurately understand or describe the reactions taking place at a molecular level.
"Commercial catalysts are like a gravel pile with many sizes of rocks. Some rocks are purple; some are blue. Some do one thing; some do another. But, our system has all the same size rocks," White said.
The model system ?in which all the molecular clusters are the same size, are evenly dispersed and are oriented in one of two directions on a single layer of titanium oxide crystals ?holds promise as a platform for studying the behavior of early transition metal oxides. White noted, "While we have created the smallest nano-cluster of a uniform size you can imagine, it is a real oxide. The tungsten is in its normal oxide state. In principle, you have all the things needed to make bonds and break bonds. That's the scientific breakthrough here."
Though it appears simple, the model system was challengin
Source:DOE/Pacific Northwest National Laboratory