Nano-sized Mn3O4 and β-MnOOH from the decomposition of β-cyclodextrin-Mn: 2. The water-oxidizing activities

•Nano-sized Mn oxides containing Mn3O4 and β-MnOOH have been prepared.•Mn3O4 and β-MnOOH have been considered for water oxidation.•β-MnOOH prepared at 450 °C is a good water-oxidizing catalyst among these Mn oxides.•Water-oxidizing activities of these compounds are compared to the other Mn oxides.

Nano-sized Mn oxides contain Mn3O4, β-MnOOH and Mn2O3 have been prepared by a previously reported method using thermal decomposition of β-cyclodextrin-Mn complexes. In the next step, the water-oxidizing activities of these Mn oxides using cerium(IV) ammonium nitrate as a chemical oxidant are studied. The turnover frequencies for β-MnO(OH) and Mn3O4 are 0.24 and 0.01–0.17 (mmol O2/mol Mn s), respectively. Subsequently, water-oxidizing activities of these compounds are compared to the other previously reported Mn oxides. Important factors affecting water oxidation by these Mn oxides are also discussed.

Graphical abstractThe water-oxidizing activities of nano-sized Mn oxides contain Mn3O4, β-MnOOH and Mn2O3 in the presence of cerium(IV) ammonium nitrate as a chemical oxidant are reported.Figure optionsDownload full-size imageDownload as PowerPoint slide