FTIR与XRD的均匀粒度分布Ce-Cu/TiO2空心微球制备机理研究

Study on Preparation Mechanism of Ce-Cu/TiO2 Hollow Microspheres with Uniform Particle Size Distribution Based on Fourier Transform Infrared Spectrum and X-Ray Diffraction

随着社会经济的发展,环境空气品质已经成为研究热点。 TiO 2是一种化学稳定性高,耐腐蚀性强,对人体无毒无害的N型半导体材料。利用TiO 2的光催化性能提高室内环境空气品质已经成为研究焦点,但是由于TiO 2只能在紫外光源下才具有较高的光催化效率,而在可见光源下的光催化效率较低,从而极大的限制了TiO 2在室内环境领域的发展。因此,研发在可见光源下具有良好光催化性能的TiO 2复合材料势在必行。利用元素掺杂改性技术与提高比表面积方法可以改善光催化反应过程中量子效率和对光能的利用率,以加快电子和空穴向表面迁移的速率同时降低光生载流子的复合机率。以二氧化硅SiO 2为模板、聚乙烯吡咯烷酮为成膜剂、硝酸铈Ce(NO 3) 3·6H 2O和硝酸铜Cu(NO 3) 2·3H 2O为改性剂采用溶胶-凝胶法制备均匀粒度分布的Ce-Cu/TiO 2空心微球,并将制备过程分为四个阶段,即纳米SiO 2球模板的制备、 Ce-Cu/TiO 2-SiO 2复合微球凝胶的制备、 Ce-Cu/TiO 2-SiO 2复合微球的制备和Ce-Cu/TiO 2空心微球的制备。利用傅里叶变换红外光谱仪(FTIR)与X射线衍射仪(XRD)对Ce-Cu/TiO 2空心微球的制备过程各阶段生成物进行测试与分析,即在纳米SiO 2球模板的制备阶段从微观角度研究纳米SiO 2球模板的搭建过程,在Ce-Cu/TiO 2-SiO 2复合微球凝胶的制备阶段研究TiO 2附着于纳米SiO 2球模板的过程,在Ce-Cu/TiO 2-SiO 2复合微球的制备阶段研究煅烧工艺对Ce-Cu/TiO 2-SiO 2复合微球中晶相与结构的影响,在Ce-Cu/TiO 2空心微球的制备阶段研究氢氧化钠溶液对Ce-Cu/TiO 2-SiO 2复合微球中纳米SiO 2球模板洗涤效果的影响。利用紫外-可见分光光度计(UV-Vis)对Ce-Cu/TiO 2空心微球的光响应性能进行测试与分析,以研究Ce-Cu/TiO 2空心微球对可见光源的利用效率。利用激光粒度分析仪(LPSA)与扫描电子显微镜(SEM)对Ce-Cu/TiO 2空心微球的粒度分布与微观形貌进行测试与分析,以研究Ce-Cu/TiO 2空心微球的均匀粒度分布效果。结果表明:以Si—O—Si基团构建非晶体结构的无定形态纳米SiO 2球模板,有利于聚乙烯吡咯烷酮在纳米SiO 2球模板表面附着,从而控制Ce-Cu/TiO 2空心微球的空腔结构。 Ce-Cu掺杂基本进入TiO 2晶体,极少进入纳米SiO 2球模板晶体,从而抑制了Ce-Cu/TiO 2-SiO 2复合微球中TiO 2由锐钛矿相向金红石相的转变。 Ce-Cu掺杂TiO 2可以促使TiO 2内部形成新的能级,实现能量较小的光子捕获e -和h +,从而提高Ce-Cu/TiO 2空心微球对可见光源的利用效率。 Ce-Cu/TiO 2空心微球的表面光滑且不存在明显的缺陷,其形貌呈现良好的球体且粒径分布均匀,即 d 90 为219.54 nm, d 50 为151.60 nm、 d 10 为103.84 nm,以及 d 90 -d 10 为115.70 nm。研究结果为进一步获得可见光源下具有良好光催化性能的均匀粒度分布Ce-Cu/TiO 2空心微球提供理论依据和研究基础。

With the development of social economy,environmental air quality has become a hot issue in the research field of indoor environmental comfort.TiO 2 was an n-type semiconductor material with high chemical stability,strong corrosion resistance and non-toxic to human body.Using TiO 2 photocatalysis performance to improve indoor air quality has become the research focus,but because TiO 2 has high photocatalytic efficiency only under ultraviolet light source,and under visible light source the efficiency was low,which greatly limits the development of TiO 2 in the field of indoor environment.Therefore,it is imperative to develop a TiO 2 composite with good photocatalytic performance under visible light source.Using the method of element doping modification technology and improving the specific surface area can improve the photocatalytic reaction in the process of quantum efficiency and utilization of energy,in order to speed up the migration rate of electrons and holes to the surface and reduce the light composite probability of carrier.In this paper,with silicon dioxide SiO 2 as template,polyvinylpyrrolidone as film-former,cerium nitrate Ce(NO 3) 3·6H 2O and copper nitrate Cu(NO 3) 2·3H 2O as modifier by sol-gel method to make Ce-Cu/TiO 2 hollow microspheres with uniform particle size distribution,and its preparation process is divided into four stages,such as preparation stage of nano SiO 2 ball template,preparation stage of Ce-Cu/TiO 2-SiO 2 composite microsphere gel,preparation stage of Ce-Cu/TiO 2-SiO 2 composite microsphere and preparation stage of Ce-Cu/TiO 2 hollow microspheres.First,the products in each stage of Ce-Cu/TiO 2 hollow microspheres were tested and analyzed by fourier transform infrared spectrometer (FTIR) and X-ray diffractometer (XRD),such as construction process of nano-SiO 2 ball template was studied from a microscopic point of view in preparation stage of nano SiO 2 ball template,attachment of TiO 2 to nano-SiO 2 ball template was studied in preparation stage of Ce-Cu/TiO 2-SiO 2 composite microsphere gel,effect of calcining process on crystal phase and structure of Ce-Cu/TiO 2-SiO 2 composite microsphere was studied in Ce-Cu/TiO 2-SiO 2 composite microsphere and effect of sodium hydroxide solution on the washing effect of nano-SiO 2 ball template in Ce-Cu/TiO 2-SiO 2 composite microsphere in Ce-Cu/TiO 2 hollow microspheres.Secondly,photoresponse performance of Ce-Cu/TiO 2 hollow microspheres were tested and analyzed by ultraviolet-visible spectrophotometer (UV-Vis),in order to study the utilization efficiency of Ce-Cu/TiO 2 hollow microspheres to visible light source.Finally,particle size distribution and microstructure of Ce-Cu/TiO 2 hollow microspheres were tested and analyzed in order to uniform particle size distribution of Ce-Cu/TiO 2 hollow microspheres.The results show that: the construction of amorphous nano-SiO 2 ball template with amorphous structure using Si-O-Si group is conducive to the adhesion of polyvinylpyrrolidone on the surface of nano-SiO 2 ball template,so as to control the cavity structure of Ce-Cu/TiO 2 hollow microspheres.Ce-Cu doping basically enters TiO 2 crystal,and rarely enters nano-SiO 2 ball template crystal,thus inhibiting the transformation of TiO 2 from anatase phase to rutile phase in Ce-Cu/TiO 2-SiO 2 composite microsphere.Ce-Cu-doped TiO 2 can promote the formation of new energy levels within TiO 2 and realize the capture of e - and h + by photons with less energy,thus improving the utilization efficiency of Ce-Cu/TiO 2 hollow microspheres to visible light source.The surface of Ce-Cu/TiO 2 hollow microspheres is smooth and there is no obvious defect.Its morphology is good and the particle size distribution is even,that is,d 90 is 219.54 nm,d 50 is 151.60 nm,d 10 is 103.84 nm,and d 90 -d 10 is 115.7 nm.The above study provides a theoretical basis and research foundation for further obtaining uniform size distribution Ce-Cu/TiO 2 hollow microspheres with good photocatalytic performance under visible light sources.