title: Reaction pathways for oxygen evolution promoted by cobalt catalyst.
abstract: The in-depth understanding of the molecular mechanisms regulating the water oxidation catalysis is of key relevance for the rationalization and the design of efficient oxygen evolution catalysts based on earth-abundant transition metals. Performing ab initio DFT+U molecular dynamics calculations of cluster models in explicit water solution, we provide insight into the pathways for oxygen evolution of a cobalt-based catalyst (CoCat). The fast motion of protons at the CoCat/water interface and the occurrence of cubane-like Co-oxo units at the catalyst boundaries are the keys to unlock the fast formation of O-O bonds. Along the resulting pathways, we identified the formation of Co(IV)-oxyl species as the driving ingredient for the activation of the catalytic mechanism, followed by their geminal coupling with O atoms coordinated by the same Co. Concurrent nucleophilic attack of water molecules coming directly from the water solution is discouraged by high activation barriers. The achieved results suggest also interesting similarities between the CoCat and the Mn4Ca-oxo oxygen evolving complex of photosystem II.
authors.affiliation: Istituto di Struttura della Materia del CNR , v. Salaria Km 29,300, C.P. 10 I-00015, Monterotondo Stazione (RM), Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Mattioli
authors.forename: Paolo
authors.initials: P
authors.lastname: Giannozzi
authors.forename: Aldo
authors.initials: A
authors.lastname: Amore Bonapasta
authors.forename: Leonardo
authors.initials: L
authors.lastname: Guidoni
mesh_terms: D002384:Catalysis; D003035:Cobalt / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D010100:Oxygen / Q000737:chemistry*; D011789:Quantum Theory; D014867:Water / Q000737:chemistry
chemical_list: D014867:Water; D003035:Cobalt; D010100:Oxygen
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