Abstract. 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 me…