论文部分内容阅读
CeO 2 nanocrystals with different morphologies were synthesized by adjusting the pH value of the starting solution in water-in-oil microemulsion.The obtained samples were characterized by transmission electron microscopy (TEM),X-ray diffraction (XRD),thermogravimetric analysis and different thermal analysis (TGA/DTA),Brunauer-Emmet-Teller (BET) surface area measurement,ultraviolet-visible absorption (UV-vis) spectroscopy and photoluminescence (PL) spectroscopy.Results show that the morphologies of CeO 2 were transformed from granular to spherical and to rod-like while the pH of the starting solution varied from 5 to 8 and to 11.All samples were indexed to the phase of CeO 2 and Ce(OH) 4,and the molar ratio of CeO 2 to Ce(OH) 4 was deduced to be about 0.25.The morphologies of CeO 2 nanocrystals had but slight influence on their specific surface areas,UV-vis spectra and PL spectra.The band gap energies of different morphological samples were estimated by UV-vis spectroscopic method.
CeO 2 nanocrystals with different morphologies were synthesized by adjusting the pH value of the starting solution in water-in-oil microemulsion. The obtained samples were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis and different Results of thermal analysis (TGA / DTA), Brunauer-Emmet-Teller (BET) surface area measurement, ultraviolet-visible absorption (UV-vis) spectroscopy and photoluminescence (PL) spectroscopy. Results show that the morphologies of CeO2 were transformed from granular to spherical and to rod-like while the pH of the starting solution varied from 5 to 8 and to 11. All samples were indexed to the phase of CeO 2 and Ce (OH) 4, and the molar ratio of CeO 2 to Ce (OH ) 4 was deduced to be about 0.25. The morphologies of CeO 2 nanocrystals had but slight influence on their specific surface areas, UV-vis spectra and PL spectra. Band gap energies of different morphological samples were estimated by UV-vis spectroscopic method.