This study brings a novel magnesium oxychloride cement-based photocatalytic material. The pH value at isoelectric point of the core-shell SiO2/CeO2 composite ultrafine particles increases from 2.2 for SiO2 paticles to 5.5, it is almost the same as that of CeO2 particles (pH=6.7). After the coating has been deposited, the surface electric characteristics of the SiO2/CeO2 core-shell particles changes. The thickness of the CeO2 shell is about 30 nm.
A CeO2 can be primarily coated onto the surface of SiO2 ultrafine particle to form a shell, with a little CeO2 deposition on the SiO2 core. The results indicate that the SiO2/CeO2 core-shell compo- site ultrafine particles have an excellent spherical morphology and uniform particle size. The structures, composition and properties of the samples were analyzed by differential scanning calorimetry-thermal gravimetric analysis, X-ray diffraction, infrared spectrometry, scanning electron microscopy, transmission electron microscopy, energy dispersive analysis and zeta potential testing. SiO2/CeO2 core-shell composite ultrafine particles were successfully synthesized by the controlling reaction factors and using the chemical precipitation method with sodium dodecyl benzene sulfonate as dispersant, cerium nitrate as cerium resource, ammonium carbonate as precipitating agent and SiO2 ultrafine particles as cores, and calcinating at 300☌ for 1 h. The effect of the ratio of the materials on the particle size and distribution of SiO2 particles were researched by the laser particle size analysis. In absolute ethanolas solvent, SiO2 ultrafine particles were prepared by sol-gel method using tetraethylorthosilicate as silicon resource, ammonia as catalyst and calcining at 500☌ for 1 h.
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