(371d) Heterogeneous Catalyst Design at the Single Atom Limit for Efficient Chemicals Production

Supported single metal atoms are a new class of catalysts in which precious metals can be used at the ultimate efficiency limit. While great strides have been made in demonstrating the potential of single-atom catalysts for many industrial reactions, there remains much debate in the literature over the nature of the active sites. Atomically dispersed supported metal catalysts offer better resource utilization and new prospects for low-cost fuel processing and green chemicals production. Single metal atom catalysts stabilized on various supports will be discussed in this presentation, drawing examples from a variety of reactions, including the low-temperature CO oxidation and water-gas shift reactions, methanol steam reforming, and selective hydrogenation and dehydrogenation reactions on single-atom alloys.We will demonstrate how reaction mechanisms involving single metal atoms/cations, transcend support structure and composition, as long as the metal atom site is allowed to form stably. A unique “signature” of the metal (Au, Pt, Pd, etc.) at the atomic state is preserved, distinct however from the corresponding extended metal surface.Selective dehydrogenation of alkanes, catalyzed by single-atom Pt/Cu support (single-atom alloy) will be presented. The activity is much higher than that of Cu, while the catalyst is coke-resistant under realistic conditions, unlike monometallic Pt.. Exploiting these promising new catalysts for the above and other reactions is a main goal of work carried out in our lab at Tufts.