介孔氧化硅/氧化铈核壳双相复合颗粒的制备及其光催化降解活性

将CeO₂纳米粒子负载在介孔氧化硅(W-mSiO₂)支撑体上，制备了核壳结构的W-mSiO₂/CeO₂双相光催化复合颗粒。用X射线衍射、扫描电镜、透射电镜、氮气吸脱附、STEM-EDX mapping、Raman光谱、荧光光谱、紫外-可见漫反射光谱等手段分析样品的结构和性质，考察了复合光催化材料对亚甲基蓝(MB)的光催化降解反应活性。结果表明，复合颗粒中介孔氧化硅内核的尺寸为180~200 nm、比表面积高达1627 m²/g，包覆层(厚度约20 nm)由大量尺寸为数纳米的氧化铈粒子组成。介孔内核对MB有较强的吸附能力，使之富集在CeO₂活性粒子周围，从而提高了复合颗粒对MB的光催化降解效果。对壳层CeO₂纳米粒子进行Er³⁺掺杂改性并在非氧化性气氛(氮气)中保护煅烧，有助于进一步提高复合颗粒对MB的光催化降解活性。

Preparation and Photocatalytic Activity of Meso-silica/ceria Binary Composites with a Core/shell Structure

In order to improve the photocatalytic activity and efficiency of ceria materials, the binary composite photocatalyst with a core/shell structure was fabricated by grafting CeO₂ nanoparticles on the surfaces of worm-like mesoporous silica supports. The prepared composite was characterized by means ofXRD, SEM, TEM, STEM-EDX mapping, UV-Vis, Raman, PL, N₂ adsorption-desorption measurements. The photodegradation towards methylene blue catalyzed by composite particles was tracked under UV irradiation. The results show that the particle size of mesoporous silica with a specific area up to 1627 m²/g is in the range of 180~200 nm, which was covered with an uniform layer of ca. 20 nm in thickness composed of a large number of nanometer ceria particles. The mesoporous cores exhibited a strong adsorption capacity for MB and therefore enriched MB around CeO₂ active nanoparticles, resulting in enhanced photodegradation activity for MB. Furthermore, it is worth noting that CeO₂ nanoparticles in the shell were doped with Er³⁺ and then calcinated in nitrogen atmosphere, can further enhance the photodegradation reaction activity of the binary composite photocatalyst.