Oxygen storage capacity of CuMO2 (M = Al, Fe, Mn, Ga) with a delafossite-type structure

Delafossite-type CuMO2 (M: trivalent cation) compounds were synthesized and found to exhibit oxygen storage capacity under oxidation/reduction cycle. The oxygen storage capacity values of CuFeO2 and CuMnO2 at lower temperature were larger than those of CuAlO2, CuGaO2- and CeO2-based materials. The large OSC includes an oxygen uptake at low temperature attributed to formation of metallic Cu by decomposition of the delafossite phase for CuFeO2 and CuMnO2. In the case of CuAlO2, which remained without decomposition below 800 °C, the oxygen uptake increased with temperature up to 0.13 mol-O/mol-CuMO2. The stability of the delafossite-type CuMO2 against oxidation/reduction cycle is affected by M3+. In this study, it was found that the oxygen storage behavior of CuMO2 can be controlled by a combination of Cu and M ions.