XAFS Analysis for Conversion of Supported Mn Species during Drying Process

抄録

The change in the chemical state of the Mn species supported on SiO2 and activated carbon (AC) during the drying process was analyzed by means of the XAFS technique. The results revealed that the change of the Mn species differs depending on the supporting material. A single change from the precursor Mn(NO3)2·6H2O to MnO2 was observed on SiO2, whereas a mixture of Mn(NO3)2·6H2O, MnO2, and Mn2O3 were appeared on AC and the composition was changed depending on the drying time. It was clarified that the oxidation from Mn(NO3)2·6H2O to MnO2 proceeded for more than 4 days at 60 °C on SiO2. With prolonged drying, there was a tendency for MnO2 to decrease and Mn2O3 to increase on AC. The oxidation of Mn(NO3)2·6H2O to MnO2 was inhibited, whereas the reduction of MnO2 to Mn2O3 was promoted significantly than on SiO2.