Microwave synthesis of cellulose/CuO nanocomposites in ionic liquid and its thermal transformation to CuO

► Cellulose/CuO nanocomposites were successfully prepared. ► A green strategy of microwave-assisted ILs method was developed. ► The heating time had an effect on the shape of products. ► The influence of the ratio of cellulose solution to ILs on the products was discussed. ► CuO materials were obtained by thermal treatment of the nanocomposites.