Synthesis of Delafossite-Type Ag0.9MnO2 by the Precipitation Method at Room Temperature

A delafossite-type Ag–Mn oxide was successfully synthesized using the precipitation method at room temperature. The delafossite is Ag+-deficient and has a chemical composition of Ag0.9MnO2. Thermogravimetry of the Ag0.9MnO2 delafossite revealed that on heating to 900 °C, it decomposed to Ag and Mn2O3 in air and to Ag and Mn3O4 under N2. While cooling to room temperature in air, the delafossite phase reformed from Ag and Mn3O4. The reversibility of the decomposition/reformation process is related to the similarity between the delafossite and spinel-type structures, both of which contain an octahedral layer. The reformation process could be used as a new synthetic route to Ag+-containing delafossite-type oxides.