(561a) Discovering Single Site and Single Atom Catalysts with High-Throughput Computational Screening

Undercoordinated midrow transition metals have unique electronic properties that make them promising catalysts for a range of reactions. Nevertheless, their properties are notoriously challenging to characterize experimentally or computationally, and it is difficult to know beforehand how a material will perform. I will describe our efforts to overcome these limitations in two classes of single site materials: doped graphitic carbon materials containing metal centers in so-called single atom catalysts (SACs) as well as at open metal sites in metal-organic frameworks (MOFs). I will describe how we have accelerated the screening of both classes of materials to address the challenge of direct partial oxidation of methane to methanol. In the case of single atom catalysts, we exhaustively screen for promising co-dopants and unearth design principles for when co-dopant atoms will improve reaction energetics. We also analyze the poor performance of scaling relations, suggesting that decoupling of reaction energies is more feasible on these SACs. In the case of MOFs, although thousands of MOFs have been synthesized, relatively few have been screened for their promise in catalysis. I will describe our high-throughput virtual screening workflow that identifies MOFs from a diverse space of experimental MOFs that have not been studied for catalysis, yet are thermally stable, synthesizable, and have promising unsaturated metal sites for C–H activation via a terminal metal-oxo species. I will describe how we carried out density functional theory (DFT) calculations on the radical rebound mechanism for methane to methanol conversion on models of the secondary building units (SBUs) from nearly 100 MOFs. We again will show how previously observed scaling relations between oxo formation and hydrogen atom transfer (HAT) are disrupted by the greater diversity of coordination environments in our MOF set. I will describe the most promising MOFs from our screen and the convergent design principles we obtain.