新型钛基氧化物纳米材料制备及其光催化性能研究

发布时间：2018-05-26 05:42

本文选题：光催化技术 + 混相TiO_2纳米片　；参考：《江苏科技大学》2015年硕士论文

【摘要】：光催化技术是通过半导体催化剂利用光子能量,将许多苛刻条件下发生的化学反应转化为在温和的环境条件下进行的技术。这一技术以其环境友好的特征在能源和环保领域发挥着独特的作用。它的兴起不仅为解决能源危机开辟了新的出路,也为保护绿色环境做出了贡献。但是,作为一种新兴的技术,光催化技术还存在一些不足之处。本文针对光催化效率低、响应区间窄等问题,提出制备2D结构的TiO2纳米片及掺杂钛酸锶(STO)纳米材料,以期全面提高现有光催化剂的光催化活性。本论文研究所涉及到的内容主要有以下几个方面:针对单相TiO2光生电子空穴复合率高的问题,本文首次使用氧化石墨烯作为牺牲模板,通过溶胶-凝胶法合成新型混相二氧化钛纳米片,来提高其光催化制氢性能。通过SEM、TEM、AFM图像分析,本文合成的二氧化钛是平均厚度为66 nm的纳米片,纳米片是由直径为15-25 nm的纳米粒子组成的混相多晶材料。XRD结果表明,样品中金红石和锐钛矿所占的比例随钛酸四丁酯的加入量的变化而变化。制氢实验结果表明,加入4 m L钛酸四丁酯(TBT-4)的样品表现出最高的氢气产量(339μmol/h),比体相材料高出47%。针对钛酸锶(STO)只对紫外光响应及水热合成法耗时的问题,本文通过微波辅助水热法一步合成La-Cr共掺杂钛酸锶(STO)纳米粒子。结果表明,微波法可在较短的时间内合成具有可见光响应能力的La-Cr共掺杂钛酸锶(STO)纳米材料。探讨掺杂量对STO光催化制氢性能的影响,结果表明,La、Cr离子的掺杂量将对掺杂STO的光催化性能产生影响。最终结果显示,当掺杂La-Cr的量为总摩尔量的5%时,其光催化制氢性能最佳。针对钛酸锶(STO)禁带宽度较宽,光响应区间较窄的问题,本文通过Cr掺杂的方法使得STO禁带宽度变窄,从而使Cr掺杂STO获得可见光下降解四环素的能力。探讨掺杂量对光催化降解四环素效率的影响,结果表明,在掺杂量为0.5%到2%时,Cr掺杂STO的光催化活性随着Cr/Sr的质量比的增加而增加,而掺杂量超出这一范围时,光催化活性随着掺杂量的增加而降低。最后通过电子自旋共振(ESR)技术和自由基捕获实验探讨Cr掺杂STO的光催化剂的降解机理,结果表明,羟基自由基和空穴在降解四环素的过程中起到重要作用。
[Abstract]:Photocatalytic technology is a technology that converts many chemical reactions under harsh conditions into mild environmental conditions by using the photon energy of semiconductor catalysts. This technology plays a unique role in the field of energy and environmental protection because of its environmental-friendly characteristics. Its rise not only opens up a new way to solve the energy crisis, but also contributes to the protection of green environment. However, as a new technology, photocatalytic technology still has some shortcomings. Aiming at the problems of low photocatalytic efficiency and narrow response range, 2D structure TiO2 nanocrystals and doped strontium titanate (STO) nanomaterials were prepared in order to improve the photocatalytic activity of existing photocatalysts. The main contents of this thesis are as follows: aiming at the problem of high recombination rate of photogenerated electron holes in single-phase TiO2, graphene oxide is used as a sacrificial template for the first time. In order to improve the photocatalytic hydrogen production, a new mixed TIO _ 2 nanocrystalline was synthesized by sol-gel method. The synthesized titanium dioxide is a nanocrystalline film with an average thickness of 66 nm, and the nanochip is a mixed polycrystalline material composed of nanometer particles of 15-25 nm in diameter. The XRD results show that the synthesized TIO _ 2 is a mixed polycrystalline material with a diameter of 15-25 nm. The ratio of rutile to anatase varies with the addition of tetrabutyl titanate. The results of hydrogen production showed that the hydrogen production of TBT-4 / TBT-4 was the highest at 339 渭 mol 路h ~ (-1), which was 47% higher than that of bulk material. In this paper, La-Cr co-doped strontium titanate (STO) nanoparticles were synthesized by microwave-assisted hydrothermal method in order to solve the problem that strontium titanate (STO) can only respond to ultraviolet light and the time consuming of hydrothermal synthesis. The results show that La-Cr co-doped strontium titanate (STO) nanomaterials with visible light response can be synthesized by microwave method in a short time. The effect of doping amount on the photocatalytic activity of STO was investigated. The results show that the doping amount of La-Cr ion will affect the photocatalytic performance of doped STO. The results show that the photocatalytic hydrogen production is the best when the amount of doped La-Cr is 5 mol / L. Aiming at the problem of wide bandgap and narrow optical response range of strontium titanate (STO), the band gap of STO is narrowed by Cr doping method, which makes Cr-doped STO obtain the ability of degradation of tetracycline under visible light. The effect of doping amount on the photocatalytic degradation efficiency of tetracycline was investigated. The results showed that the photocatalytic activity of Cr doped STO increased with the increase of the mass ratio of Cr/Sr when the doping amount was between 0.5% and 2%, and when the doping amount exceeded this range, the photocatalytic activity of Cr doped STO increased with the increase of Cr/Sr mass ratio. The photocatalytic activity decreases with the increase of doping amount. Finally, the degradation mechanism of Cr-doped STO photocatalyst was investigated by electron spin resonance (ESR) technique and free radical capture experiment. The results show that hydroxyl radical and hole play an important role in the degradation of tetracycline.
【学位授予单位】：江苏科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1;TQ116.2

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