(261b) Atomically Dispersed Pt-Group Metal Catalysts: Uniformity, Structural Evolution and Pathways to Increased Functionality

The use of oxide-supported atomically dispersed Pt-group metal atoms (or ions) as catalytic active sites is of interest due to their distinct reactivity compared to metal clusters and efficient metal utilization. Relationships between the structure of these active sites, their dynamic response to environments, and catalytic functionality have proven difficult to experimentally establish. Here I will describe recent research efforts from my group into 4 aspects of this class of materials: distinct reactivity, uniformity, structural evolution, and pathways to increased functionality.

To motivate the study of this class of materials I will highlight a few cases where we have observed distinct selectivity for catalytic processes occurring on atomically dispersed metal catalysts as compared to metal clusters including: CO₂ reduction by H₂, methanol carbonylation, hydrodeoxygenation of m-cresol, and the reduction of NO by CO in wet environments. I will then highlight the critical role of local coordination uniformity and structural evolution under reaction conditions when developing structure-function relationships. Insights into uniformity and structural evolution are achieved through the synthesis atomically dispersed metal species on oxides supports at very low loadings (< 0.05 wt.%) and analysis of their local coordination through in-situ atomic resolution microscopy and spectroscopy-based characterization supported by first principles calculations. Finally, I will highlight pathways to increasing complexity and functionality of atomically dispersed metal catalysts through the modification of their local coordination environments with inorganic and organic species that influence catalytic processes.