(90g) Structural and Dynamic Characteristics of Supported Metal Catalysts at the Atomic Scale

The use of heterogeneous catalysts for important chemical conversions ranging from pollution mitigation to energy production relies on the design of active catalytic sites consisting of metal nanostructures supported on high surface area oxide materials. Key to design of these systems is identifying active site geometries and compositions that are optimized for desired catalytic reactions. These active sites vary in structural diversity from single atoms on oxide supports to unique interfaces between active metal species and oxide supports, making their characterization complex. This difficulty is further complicated because the exposure of oxide-supported metals to reactive environments can induce significant transformations in the structure of metal surfaces, support surfaces, and interactions between the metal and support. The dynamic transformation of catalytic structures induced by exposure to reaction conditions can cause significant changes in reactivity, requiring detailed in-situ analysis to identify active site motifs. I will highlight examples where we have exploited in-situ and ex-situ spectroscopy and microscopy to characterize heterogeneous catalysts at atomic scale, identify how reactive conditions modify active site structures, and relate this to catalytic performance.