A team at Stanford University and the Department of Energy’s SLAC National Accelerator Laboratory has identified exactly which pairs of atoms in a nanoparticle of palladium and platinum – a combination commonly used in converters – are the most active in breaking those gases down.
They also answered a question that has puzzled catalyst researchers: Why do larger catalyst particles sometimes work better than smaller ones, when you’d expect the opposite? The answer has to do with the way the particles change shape during the course of reactions, creating more of those highly active sites.
The results are an important step toward engineering catalysts for better performance in both industrial processes and emissions controls, said Matteo Cargnello, an assistant professor of chemical engineering at Stanford who led the research team. Their report was published June 17 in Proceedings of the National Academy of Sciences.
Significance (from PNAS Publication)
Catalysts are essential for a sustainable future because they reduce the energy required in chemical processes and the emission of harmful and polluting compounds. Revealing the function and structure of a working catalyst is a challenging task but critical in order to prepare more efficient and higher-performing materials. Very often, active sites are formed by many atoms that cooperate to perform the catalytic function. It is therefore challenging to identify the structure of the active site. Here, we combine uniform nanocrystal catalysts and theory insights to reveal the active-site ensemble necessary for alkene combustion. This approach can be extended to reveal atomistic details of working catalysts for a variety of applications.