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Energetic basis of catalytic activity of layered nanophase calcium manganese oxides for water oxidation.

ABSTRACT: Previous measurements show that calcium manganese oxide nanoparticles are better water oxidation catalysts than binary manganese oxides (Mn3O4, Mn2O3, and MnO2). The probable reasons for such enhancement involve a combination of factors: The calcium manganese oxide materials have a layered structure with considerable thermodynamic stability and a high surface area, their low surface energy suggests relatively loose binding of H2O on the internal and external surfaces, and they possess mixed-valent manganese with internal oxidation enthalpy independent of the Mn(3+)/Mn(4+) ratio and much smaller in magnitude than the Mn2O3-MnO2 couple. These factors enhance catalytic ability by providing easy access for solutes and water to active sites and facile electron transfer between manganese in different oxidation states.

SUBMITTER: Birkner N

PROVIDER: S-EPMC3670370 | biostudies-literature | 2013 May

REPOSITORIES: biostudies-literature

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Energetic basis of catalytic activity of layered nanophase calcium manganese oxides for water oxidation.

Birkner Nancy N Nayeri Sara S Pashaei Babak B Najafpour Mohammad Mahdi MM Casey William H WH Navrotsky Alexandra A

Proceedings of the National Academy of Sciences of the United States of America 20130510 22

Previous measurements show that calcium manganese oxide nanoparticles are better water oxidation catalysts than binary manganese oxides (Mn3O4, Mn2O3, and MnO2). The probable reasons for such enhancement involve a combination of factors: The calcium manganese oxide materials have a layered structure with considerable thermodynamic stability and a high surface area, their low surface energy suggests relatively loose binding of H2O on the internal and external surfaces, and they possess mixed-vale ...[more]

PMID: 23667149

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