Synthesis of Cu-doped nano-TiO2 by detonation method

Cu-doped nano-TiO2 was successfully prepared by detonating a mixture of metatitanic acid, cupric citrate, ethylene glycol, and hexogen with specific mass ratio in a closed container. The samples were characterized using an X-ray diffractometer (XRD), transmission electron microscope, high-resolution transmission electron microscope, energy dispersive x-ray spectrometer, UV–vis spectrophotometer, and FTIR spectrophotometer. Results showed that the samples comprising the mixed crystal of anatase and rutile were the most irregularly shaped particles, exhibiting poor dispersion. The 550 °C high-temperature heat treatment could improve the dispersion, with crystal size of 10–30 nm. The diffraction peak of the copper oxide appeared on the XRD pattern with the increase in Cu doping concentration. Cu doping could reduce the band gap of TiO2 and enhance visible light absorption. New absorption peaks appeared on the infrared absorption spectrum of TiO2 after Cu doping, and energy levels were observed in the energy gap of TiO2. The photocatalytic properties of TiO2 could be enhanced by increasing the Cu doping concentration. The initial concentration of methyl orange solution negatively correlated with the photocatalytic properties of TiO2, whereas the degradation rate of methyl orange solution increased with increasing TiO2 dosage. An almost linear relationship was observed between TiO2 dosage and degradation rate. The concentration of the Cu-doped sample had a significant impact on the degradation rate of methyl orange solution.