Molecular catalysts’ advantages include high activity, facile characterization of intermediates, kinetic studies, and easy catalyst optimization. However, these properties are almost always trumped by the two key properties of heterogeneous catalyst, recyclability and stability, for large scale implementation. One strategy to combine the two is to modify the ligands of the catalyst with functional groups that can form bonds with a solid support, or functional groups like pyrene that could adhere to support carbon nanotubes (CNT). There are a number of successful examples of pyrene substituted catalysts and we focused on a Ru catalyst for H<sub>2</sub>O oxidation. While recyclability and sometimes stability is gained when the catalysts are grafted, the details of the reaction mechanism is now very difficult to study due to limitations of spectroscopic techniques when solid surfaces are present. The size of the system is also too large for both periodic DFT used in surface chemistry studies, and for standard molecular quantum chemistry. To get understand involving surface adhered molecules we employed classical physical methods extended with the empirical valence bond method. This methodology was recently used to study catalyst fully dynamically in water solution.<sup>1</sup> In this way we have been able to study several aspects that was never considered in computational simulations before including 1) surface diffusion of the catalyst and collision frequencies of bimolecular reactions 2) activation energy at hydrophobic/water interfaces and the compared them to homogeneous phases 3) binding free energies of catalyst to each other and the surface. From these data we have a clear picture of the catalysts and its behavior in an environment never studied previously in this detail, and the agreement with experiments is striking.

Modeling molecular water oxidation catalysts at interfaces

255th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.