Solvothermal synthesis of Cr2O3 nanocubes via template-free route

Cr2O3 nanocubes with porous structure were synthesized by solvothermal method at 150 degrees C/24 h using potassium dichromate (K2Cr2O7), N, N-dimethyl forrhamide (DMF) and water. Crystallization of Cr2O3 was noticed at 400 degrees C. The vibration bands at 564 cm(-1) and 629 cm(-1) signified to Cr-O stretching of Cr2O3, and the intense Raman peak at 532 cm(-1) was assigned to A(1g) symmetry of Cr2O3. The XPS results show the binding energy of 576.8 eV, and 586.4 eV corresponding to Cr 2p(3/2) and Cr 2p(1/2), respectively of Cr 2p of Cr2O3 phase. The absorption peaks at 455 nm and 600 nm reflect the d(3) electronic transition of Cr3+ ion attributing to (4)A(2g) --> T-4(1g) and (4)A(2g) --> T-4(2g), respectively. The size of the nanocubes was about 50-200 nm. The BET surface area and total pore volume of 400 degrees C- treated sample were found to be 23 m(2) g(-1) and 0.18 cm(3) g(-1), respectively. (C) 2015 Elsevier B.V. All rights reserved.