Silicon dioxide coating of CeO2 nanoparticles by solid state reaction at room temperature

The synthesis of SiO2 coated CeO2 nanoparticles by humid solid state reaction at room temperature is described. Transmission electron microscope results show that CeO2 particles were coated with a layer of SiO2. Binding energy of Ce 3d5/2 was shifted from 883.8 to 882.8 eV after coating in the XPS Ce 3d spectra. This confirms the chemical bond formation between SiO32− and Ce4+. Because the surface photovoltage property of CeO2 nanoparticles that were used as core materials in the experiment approaches to that of CeO2 macroparticles, peak P2 (electron transition from O 2p on surface to Ce 4f) disappeared in the surface photovoltage spectrum of CeO2 nanoparticles. Also, the effect of SiO2 on the electron transition from O 2p to Ce 4f results in the lowering of surface photovoltage response intensity of P1 peak (electron transition from O 2p in bulk to Ce 4f).