Fe_3O_4@SiO_2@TiO_2磁性纳米复合颗粒的制备及光催化性能研究

A Study on Synthesis and Photocatalytic Property of Fe_3O_4@SiO_2@TiO_2 Magnetic Multifunctional Nanoparticles

首先运用共沉淀法制备出纳米级的Fe_3O_4,然后采用溶胶-凝胶-水热法制备出Fe_3O_4@SiO_2@TiO_2的复合物。通过XRD对复合物的晶形进行表征,证明有SiO_2和TiO_2的存在,且TiO_2为锐钛矿型,有助于提高复合物的光催化性能。通过TEM、BET和红外光谱等测量技术对复合物的形貌、粒径和表面物理性能等进行表征。结果显示:Fe_3O_4@SiO_2@TiO_2颗粒尺寸大约为30~50 nm,形成了更加均匀稳定的核壳结构,增加的SiO_2壳层可以增加Si-OH键,有利于纳米TiO_2通过氢键作用形成复合物。内核的表面官能团,更加有利于TiO_2的包覆,有助于提高复合物的光催化性能。Fe_3O_4@SiO_2@TiO_2的催化性能更加优异,接近于纯TiO_2的催化性能。而这种磁性负载光催化剂可以很方便地与溶液分离,拥有纯TiO_2不具备的良好的重复利用性。

Fe3O4 nanoparticle was first synthesized by coprecipitation method and Fe3O4@SiO2@TiO2 composite was prepared by sol-gel-hydrothermal method. XRD composite and the TiO2 was anatase helpful to improve results showed that SiO2 and TiO2 existed in the the photocatalytic activity of the Fe3O4@SiO2@TiO2 composite. The morphology, particle sizes and physical properties of the samples were characterized by TEM, BET and FTIR. The results showed that the particle size of Fe3O4@SiO2@TiO2 was around 30-50 nm, and formed more uniform and stable core-shell structure. The shell of SiO2 could offer Si-OH bond in the composite, more favorable for the formation of the composite through hydrogen bond for TiO2 nanoparticles （NPs） and thereby the core of TiO2 could be coated more uniformly. Besides, the catalytic properties of Fe3O4@SiO2@TiO2 are improved much, close to that of pure TiO2. It is much easier for the magnetic supported Fe3O4@SiO2@TiO2 photocatalyst to be separated from solutions and reused than pure TiO2 NPs.