Electrocatalytic Oxygen Evolution from Water on a Mn(III-V) Dimer Model Catalyst - A DFT Perspective
Artikel i vetenskaplig tidskrift, 2011

A complete water oxidation and oxygen evolution reaction (OER) cycle is monitored by means of Density Functional Theory (DFT). A biomimetic model catalyst is employed, comprising a m-OH bridged Mn(III-V) dimer truncated by acetylacetonate ligand analogs and hydroxides. The reaction cycle is divided into four electrochemical hydrogen abstraction steps followed by a series of chemical steps. The former employ the Tyrosine/Tyrosyl radical acting as electron and proton sink thus determining the reference potential. Stripping hydrogen from water leads to the formation of two highly unstable Mn(V)=O/Mn(IV)-O· moieties, which subsequently combine to form a peroxy O-O bond. O2 evolution results from subsequent consecutive replacement of remaining Mn-O bonds by water. Conditions for the validities of GGA DFT and self-interaction error corrected hybrid DFT predictions despite the presence of a manifold of near-degenerate spin states, are discussed in some detail. The applicability of the former is extended to include the rate limiting steps in the OER.

proton shuttle

Water Oxidation

Oxygen evolution

mechanism

binuclear site

rate limiting step

double-exchange

Författare

Michael Busch

Göteborgs universitet

Elisabet Ahlberg

Göteborgs universitet

Itai Panas

Chalmers, Kemi- och bioteknik, Oorganisk miljökemi

Physical Chemistry Chemical Physics

1463-9076 (ISSN) 1463-9084 (eISSN)

Vol. 13 15069-15076

Styrkeområden

Nanovetenskap och nanoteknik

Energi

Materialvetenskap

Ämneskategorier

Bearbetnings-, yt- och fogningsteknik

Annan kemiteknik

Annan kemi

Teoretisk kemi