Atomic Scale Insights into Single-Atom Catalysis Vacuum Experiments on Model Systems Are Helping To Uncover The Workings Of Novel Catalytic Materials

Single-Atom Catalysis (SAC) is a rapidly emerging field aimed at minimizing the amount of precious metals required to perform important catalytic reactions. Modern heterogeneous catalysts already utilize nanoparticles containing 100s to 1000s of atoms on an inexpensive support, but the dream of SAC is to do the same chemistry with single atoms. The concept is firmly entrenched, and SAC systems have demonstrated activity for a variety of reaction, metal, and support combinations. Nevertheless, the topic remains controversial because it is extremely difficult to characterize a catalyst based on single atom active sites, and even harder to figure out how they work. In our group in Vienna, we study model SAC systems in a highly controlled ultrahigh vacuum environment using a variety of state-of-the-art surface-science techniques to discover what makes a stable single atom catalyst, the mechanisms underlying their catalytic activity, and the processes leading to their deactivation.