Study On The Synthesis Of CeO₂Particles By The Control Of CTAB And The Mechanism Of CTAB As A Template

Since CeO2possesses excellent redox ability and specific crystal structure,so itis a type of extensive used materials. In the process of the preparation of CeO2powdermaterials, how to control the morphology and size of the particle effectively hasattracted great a great deal of attention. In this paper, spherical CeO2powder materialswere synthesized by the gas diffusion method using Ce(NO3)3as raw materials andcetyltrimethylammonium bromide (CTAB) as template in the light of biomineralization.The obtained products were characterized by means of SEM,XRD,TG-DTA,FT-IR,laser particle sizer, nitrogen physisorption. The influence of the concentration of CTAB,the concentration of cerium nitrate, pH value and reaction time on the morphology andparticle size of CeO2particles was investigated. The mechanism of CTAB as atemplate were also discussed. The main results concluded in this paper are listed asfollows:The optimal preparation conditions were obtained: the concentration of CTAB is1.5g/L, the concentration of cerium nitrate is0.03mol/L, pH value is5and the reactiontime is30days;The analysis of the obtained products showed that the obtained productsprepared at optimum condition exhibited bimodal, asymmetric and right leaning(theskewness Sk1>0) form in the size-frequency curves. The obtained products in thepresence of1.5g/L CTAB and without CTAB exhibited the average diameters of51and57respectively. Compared with the obtained products without CTAB, theobtained products prepared at optimum condition exhibited smaller size and larger BETsurface area. The UV-vis absorption spectra of the obtained products prepared atoptimum condition exhibited absorption peak at380nm and243nm respectively.Compared with the obtained products without CTAB, the obtained products prepared atoptimum condition exhibited stronger ultraviolet absorption performance.The obtained precursors at optimum condition exhibited a main crystalline phasesof trivalent(Ce3+) orthorhombic Ce2O(CO3)2H2O and a small number of trivalent Ce(OH)3,which was characterized by Fourier transform infrared (FT-IR),TG-DTA andX-ray diffraction(XRD). CTAB could be used as an efficacious crystal growth modifierto induce the self-assembly of precursors, control the crystallization growth of precursorof CeO2and control the morphology of CeO2particles by thermal decomposition of theprecursors via the positively charged CTA+and CO32-functional groups electrostaticmatching at room temperature.