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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 2: Modeling and Simulation of Soft Matter I
CPP 2.10: Vortrag
Montag, 18. März 2024, 12:15–12:30, H 0107
Single Atom Catalysis in aqueous conditions: enhanced interfacial water dissociation on a Fe-porphyrin graphene defect — •Laura Scalfi1, Maximilian R. Becker1, Roland R. Netz1, and Marie-Laure Bocquet2 — 1Freie Universität Berlin, Berlin, Germany — 2Ecole Normale Superieure, Paris, France
SAC or Single-Atom-Catalysis is an expanding field of heterogeneous catalysis and is particularly relevant for electrocatalysis in aqueous solutions. In SAC, the catalytically active metallic sites are reduced to single metal ions that are typically supported on a carbon scaffold. It therefore consumes less metallic material, which is an important environmental and economic factor.
Ab initio modelling and experiments mostly propose two types of defects around single metallic sites on graphene scaffolds with pyridine-like or porphyrin-like motives. Most fundamental studies however neglect the solvating water molecules. Here, we investigate how the liquid interfacial water environment interacts with a single Fe ion using extensive spin-polarized density-functional-theory molecular dynamics simulations. We show that both the porphyrin and pyridine Fe SACs spontaneously adsorb two interfacial water molecules from the solvent on opposite sides and unveil a different catalytic reactivity of the two hydrated SAC motives: while the Fe-porphyrin defect eventually dissociates an adsorbed water molecule under a moderate external electric field, the Fe-pyridine defect does not convey water dissociation. This work highlights the major role that solvents can play and the importance of including them explicitly in molecular studies.
Keywords: single atom catalysis; water dissociation; ab initio molecular dynamics; energy materials; green chemistry