Preparation,Structure,UV-sheilding And Absorbent Property Of Nano CeO₂ Hollow Sphere

Cerium of rare earth metal is more abundant in Earth. Ceria is technically important ma-terials due to its wide application in catalyst, polishing, UV-shielding, ceramics, adsorption in wastewater and other contaminants. As an n-type semiconductor, the band gap of CeO₂ is 2.94 eV and its light absorption threshold is about 420 nm. The light whose wavelength is less than 420 nm could be absorbed by CeO₂ in theory. CeO₂ have a good prospect in VU-shielding and its optical and catalytic properties are very excellent, which causes there is little articles in terms of its adsorption property.This paper presents the facile preparation of CeO₂ nanoparticles hollow spheres by sol-gel method and calcination. Using the control variable method, effects on the morphology of hollow sphere from water bath temperature, amount of Ce?NO3?3-6H2O, amount of NH₃·OH and calcination temperature were studied, and the formimg mechanism of CeO₂ hollow spheres was also studied. TEM, SEM and DLS were adopted to investigate the size and surface morphology of cerium oxide hollow sphere, and XRD and BET were used to in-spect the crystal structure of hollow sphere, and surface area and pore size diameter. The main conclusions are as follows:1. CeO₂ hollow sphere has a porous structure. Its surface area could reach up to 67.2m2 g"1 and its average diameter 200 nm. Its shell is composed of smaller cerium oxide particles with diameter about 6 nm-10 nm and the thickness about 25 nm.2. The obtained samples shows a good adsorption performance in the typical leather dye ?AB 21-. ABr 97 and AR 97 dye?. The result indicated that CeO₂ hollow spheres can effec-tively deal with high and low concentrations of azo dye. And CeO₂ hollow spheres have a good recycling rate and strong deformation resistance.3. The obtained samples have a strong absorption to ultraviolet region whose wavelength is less than 400 nm and almost do not absorb visible light whose wavelength is longer than 450 nm. This provides a new program to prepare the material with high performance in UV-shielding.