Catalysis Today, Vol.321, 128-134, 2019
Photoelectrodeposition effect of lanthanum oxide-modified ceria particles on the removal of lead (II) ions from water
The photocatalytic capabilities of La2O3 incorporated in CeO2 for the removal of Pb(II) ions in water are reported in this work. La2O3-modified CeO2 particles are prepared by a solid-state reaction method at calcination temperature of 1000 degrees C and 1400 degrees C. The x-ray diffraction result demonstrates a solid solution Ce0.9La0.1O1.95 phase coexisting with the CeO2 matrix phase (Ce0.9La0.1O1.95-CeO2) obtained at a calcination of 1400 degrees C, while the mixed La2O3/La(OH)(3)-CeO2 phase is obtained at 1000 degrees C. The UV-photocatalytic activity for Pb(II) ion removal of the La2O3-modified CeO2 particles is significantly higher than that of pure CeO2. Ce0.9La0.1O1.95-CeO2 particles show stronger visible light absorption capacity and higher ability of photoelectrodeposition for the Pb(II) ion removal than the mixed La2O3/La(OH)(3)-CeO2 particles and pure CeO2. The high photocatalytic activity is supported by a strong photoluminescence signal from the Ce0.9La0.1O1.95-CeO2 particles, suggesting a high efficiency of photogenerated charge separation. A formation of p-type Ce0.9La0.1O1.95 and n-type CeO2 heterojunctions in Ce0.9La0.1O1.95-CeO2 particles also promote photogenerated charge transfer and efficiency restraining recombination of the charges.