Preparation and photocatalytic performance of Cu-doped CeO2 by citrate combustion method

Cu-doped cerium oxides were successfully prepared by nitrate combustion method. The crysatlline phase evolution, micro morphology and photocatalytic performance of the products are systematically studied by XRD, SEM/EDX and degradation rate of methylene blue. The results show that at relative low temperature (<600°C), 20 mol% copper can be dissolved into CeO2 fluorite type cubic structure, however, at high temperature of 700°C, CuO phase desolution from CeO2 solid solution is detected by XRD, and confirmed by DTA for 5% Cu-doped sample. The as prepared photocatalysts show agglomeration of ultra fine particles with porous structure. Degradation results of methylene blue indicate that better photocatalytic performance is obtained for 5% Cu-doped CeO2 under the stimulated visible light than UV light irradiation (both 254 nm and 365 nm), even the power of former is half of the later. The loss of photocatalytic activity for higher doping samples (>5% Cu) is believed to be the serious agglomeration of the particles and desolution of CuO from CeO2 solid solution.