Hexagonal polytype of CuCrO2 nanocrystals obtained by hydrothermal method

Abstract

We had first synthesized hexagonal 2H-CuCrO2 nanocrystals by hydrothermal method. The stability diagram for Cu–Cr–Na–H2O system allows preparing of nanocrystalline CuCrO2, either 2H or 3R pure phase, by a single step, low-temperature hydrothermal synthesis. 2H- and 3R-CuCrO2 quasi-hexagonal shape nanocrystals have shown a wide range of size distribution varying from about 20 to 40 nm. An unexpected result is that 2H-CuCrO2 phase was a low temperature phase in the hydrothermal synthesis. Also, a formation mechanism for the synthesis of CuCrO2 nanocrystal, 2H- and 3R-polytypes was proposed.