一步合成核壳结构C-TiO_2复合材料及UV-Vis光催化降解染料

Yolk-shell C-TiO_2 composites: one-step synthesis and their UV-Vis light-driven photocatalytic properties for dyes

以二(乙酰丙酮基)钛酸二异丙酯,异丙醇和尿素为原料,通过简单的一步无模板溶剂热法合成了核壳结构C-TiO_2复合材料前驱体,随后在氩气条件下不同温度煅烧得到高晶相CTiO_2复合材料。运用SEM、TEM、XRD、XPS、Raman、TG、N_2吸附-脱附、UV-Vis漫反射等技术对样品进行表征、并在UV-Vis光照射下分别对Rh B、MB、CR 3种染料溶液进行了催化降解测试。结果表明:550℃煅烧的样品的催化性能最佳,其为高晶相的锐钛矿相TiO_2材料,并包含少量的碳,而且550℃煅烧的样品依然保持了核壳结构。比表面积能够达到85.69 m^2/g、孔直径为16.4 nm、孔体积为0.423 m^3/g。其优越的催化性能可归于较大的比表面积能够提供吸附更多的染料分子;核壳结构更有利于捕获更多的光量子;高晶相更有利于催化过程中电子-空穴对的分离。

Herein, the yolk-shell C-TiO2 precursors were successfully fabricated by a one-step template-free solvothermal method using titanium diisopropoxide bis （acetylacetonate）, isopropyl alcohol and urea as raw materials, followed by calcination at different temperatures in argon. The obtained samples were characterized by SEM, TEM, XRD, XPS, Raman spectra, TG, N2 adsorption-desorption isotherms and UV-Vis diffuse reflectance spectra, then further measured their photocatalysis for degradation of RhB, MB and Congo red under UV-Vis light irradiation. Experimental results reveal that the products of calcination at 550℃ in argon exhibited the best photocatalytic properties. It is anatase TiO2 with high crystallinity and contains a little carbon, their yolk-shell frames could be obtained when the temperature up to 550℃ and also possesses a relatively high surface area of 85.69 m^2/g, large pore size of 16.4 nm and high total pore volumes of 0. 423 m^3/g. The enhanced photocatalytic degradation performance maybe ascribed to their large surface area for dye molecule loading, yolk-shell frames possesses a good capability for light scattering for enhancing the light-harvesting and high crystallinity that favors the separation of photogenerated electron-hole pairs.