The role of an oxometallic complex in OH dissociation during water oxidation: A microscopic insight from DFT study

Soumyajit Sarkar, Mukul Kabir, Martha Greenblatt, Tanusri Saha-Dasgupta

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

The uncatalyzed atomic dissociation of water requires breaking of a strong O-H bond with an enthalpy of 494 kJ mol-1, which necessitates the understanding and designing of appropriate catalysts. Here we employ transition state theory within quantum chemical density functional theory to understand the role of metal-oxide inorganic complexes in the OH → O + H process, the most important reaction in water oxidation. We study the effect of (a) chemical bonding in different M4O4 (M = Mn, Co) cubane complexes, (b) heterocubane geometry containing Ca, in addition to a transition metal ion, (c) dimensionality by considering both three-dimensional and two-dimensional geometry of the oxometallic unit, and (d) connectivity between two oxometallic cubane units, corner shared versus edge shared geometry. Analysis of our density functional theory based calculations singles out a robust microscopic quantity among various plausible and competing factors, which elucidates the important role of metal-oxygen covalency at the oxidized site. The M-O bonding strength inversely determines the strength of the O-H bond, and thus the energy required for OH dissociation. This provides one with an important microscopic design principle for a metal-oxide complex catalyst responsible for water oxidation.

Original languageEnglish (US)
Pages (from-to)10422-10428
Number of pages7
JournalJournal of Materials Chemistry A
Volume1
Issue number35
DOIs
StatePublished - Sep 21 2013

ASJC Scopus subject areas

  • Chemistry(all)
  • Renewable Energy, Sustainability and the Environment
  • Materials Science(all)

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