For NaOH content ranging from 1to 3M, CuCrO2 was obtained as a major phase. After reaction,precipitate was filtered and washed with absolute alcohol anddeionized water in sequence several times. The product was driedin an oven at 80 ◦C for 8 h. CuCrO2 microcrystals were synthesizedby sol–gel method according to the literature report [14,15],