Water Oxidation by λ-MnO2: Catalysis by the Cubical Mn4O4 Subcluster Obtained by Delithiation of Spinel LiMn2O4

David M. Robinson, Yong Bok Go, Martha Greenblatt, G. Charles Dismukes

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217 Citations (Scopus)


Nanocrystalline spinel LiMn2O4 has been prepared and treatment of LiMn2O4 with dilute nitric acid solution resulted in the delithiation of the framework, while maintaining the spinel structure, λ-MnO2. LiMn2O4 is not a catalyst for water oxidation. Upon removal of the lithium, the cubical Mn 4O4 cores become active sites for oxidizing water to molecular oxygen, which was investigated with the photochemical [Ru 2+(2,2′-bpy)3]/persulfate system at pH 5.8. The nanosize λ-MnO2 obtained from the nanocrystalline LiMn 2O4, which was synthesized by the citrate route, shows a significantly higher water oxidation catalytic activity (Turnover Frequency: 3 × 10-5 mol O2/s/mol Mn) than that obtained via solid state reaction with micrometer and irregular particle sizes (Turnover Frequency: 5 × 10-6 mol O2/s/mol Mn).

Original languageEnglish
Pages (from-to)11467-11469
Number of pages3
JournalJournal of the American Chemical Society
Issue number33
Publication statusPublished - Aug 25 2010

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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