UCLA

Realistic modelling of catalysis requires the incorporation of complexity in the form of fluxionality. This means the inclusion of multiple thermally accessible isomers in the starting ensemble, and along potential reaction pathways. Furthermore, the role of fluxionality on fundamental physical behavior of the system must also be accounted for. This work focuses on extending this fluxionality paradigm both along reaction mechanisms to capture the full complexity of experiment, as well as part of the fundamental physical processes of cluster catalyst deactivation such as sintering or poisoning. Fluxionality is incorporated into DFT calculations via global optimization of cluster catalyst structures and relevant reaction intermediates. It essential to account for isomeric diversity for improved interpretation of experimental results, which enables the identification of novel size-dependent sintering behavior that has subsequently been confirmed experimentally. Furthermore, this allows us to go beyond simple interpretation of experimental results to more complex predictions of changes in the structure and composition of the system. For example, this enabled the pre- diction of self-limiting coke formation in Pt4Ge systems, and aided in understanding why Pt4 in contrast rapidly continues to coke.