摘要：BiFeO3是一种具有铁电性和铁磁性的单相多铁材料，在信息存储、自旋电子器件、电容-电感一体化中具有潜在应用。BiFeO3作为一种非化学计量比的钙钛矿材料，具有较窄的光学带隙，其纳米材料还具有优异的光催化和气敏性能。

本文采用溶胶凝胶法制备Sr掺杂的BiFeO3纳米颗粒，利用热重-差热分析（TG-DTA)、X射线衍射仪（XRD）、扫描电子显微镜（SEM）表征了材料的微结构和微观形貌。结果显示当温度为450℃～550℃温区，Sr掺杂的BiFeO3是单相扭曲的三方晶体结构（空间群R3c）。颗粒分布均匀，平均尺寸为60nm。以上结果表明采用酒石酸溶胶凝胶法能够实现BiFeO3纳米颗粒的低温生长，得到完美的纳米晶粒。利用紫外分光光度计和智能气敏分析系统进一步表征了Sr掺杂的BiFeO3纳米颗粒的性能，结果表明BiFeO3纳米颗粒的光学带隙约为2.2eV，Sr掺杂量为10%的BiFeO3纳米颗粒对350-560nm波段的光谱吸收度相比未掺杂BiFeO3纳米材料提高约为40%。Sr掺杂量为10%的BiFeO3纳米颗粒催化降解时间约为90min，相较BiFeO3纳米颗粒催化时间提高约为60min。在240℃工作温度下，Sr掺杂量为5%的BiFeO3纳米颗粒对酒精和丙酮表现出极强的气敏性，对50ppm的酒精和丙酮的灵敏度分别为54和47.5。

关键字：BiFeO3；溶胶凝胶法；掺杂；光催化；气敏性

Abstract：BiFeO3 is a single-phase multi-iron material of Ferroelectricity and Ferromagnetism, It has potential application in the area of information storage, spin electronic devices, capacitor - inductor integration. BiFeO3 has a narrow optical band gap as a kind of non-stoichiometric perovskite material, and its nanomaterials have excellent photocatalytic and gas-sensing properties.

In this paper, Sr-doped BiFeO3 nanoparticles were prepared by sol-gel method. The microstructure of the material were characterized by thermo-gravimetric analysis (TG-DTA),  X-ray  powder  diffraction  (XRD)  and  scanning  electron    microscopy (SEM)  .  The  results  show  that  in  the  temperature  range  from  450℃ to   550℃,Sr-doped BiFeO3 is a single-phase twisted three-crystal structure (space group R3c). The nanoparticles were evenly distributed and the average size was 60 nm.The results show that low temperature growth of BiFeO3 nanoparticles can be achieved by tartaric acid sol-gel method, and perfect nanocrystalline grains were obtained.

Properties of Sr-doped BiFeO3 nanoparticles were further characterized by UV spectrophotometer and intelligent gas analysis system, The results show that the optical bandgap of BiFeO3 nanoparticles is about 2.2eV Compared with undoped BiFeO3 nanomaterials, spectral absorbance of sample with 10% Sr content has increased about 40% in the wavelength range from 350-560nm. Catalytic degradation of 10% Sr content sample was about  90min.  The catalytic time of BiFeO3  nanoparticles  was  increased  by 60 min.

Working temperature was 240℃, Sr 5% of BiFeO3  nanoparticles showed strongly gas sensitivity to alcohol and acetone, Its sensitivity to 50 ppm of alcohol and acetone was 54 and 47.5, respectively.

Key words: BiFeO3; sol-gel; doping; photocatalytic; gas sensing

目录

摘要 1

Abstract 1

第一章绪论 1

1.1 引言 1

1.2 背景研究 1

1.2.1BiFeO3的结构 1

1.2.2BiFeO3的性能 2

1.3光催化、气敏性机理