Hydrothermal synthesis and characterization of nanocrystalline Zn–Mn spinel

Hydrothermal method had been used to successfully synthesize the nanocrystalline spinel zinc manganese oxide (ZnMn2O4) directly from Zn(CH3COO)2·2H2O, NaOH, Mn(NO3)2 and H2O2 at 170 °C for the reaction time of 48 h. The effects of the synthesis conditions, such as the Zn/Mn molar ratio, the reaction temperature, the reaction time, the zinc source and the concentrations of NaOH and H2O2, on the formation of the Zn–Mn spinel were investigated. The products were characterized by means of X-ray diffraction (XRD), inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The results indicated that the compositions of the Zn–Mn spinel with the tetragonal structure were Zn1.14Mn1.86O4. Scanning electron microscope (SEM) and transmission electron microscopy (TEM) images showed that the products at 170 °C were with square-shaped nanocrystalline spinel with the particle size of about 20–50 nm. The thermal behaviors of the products were investigated by thermogravimetric analysis (TG).