碳纳米管负载二氧化钛的制备及对有机物光催化性能的研究

发布时间：2018-03-10 19:15

  本文选题：亲水性　切入点：羧基化碳纳米管　出处：《天津工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：二氧化钛是一种安全无毒、化学活性高、价格低廉、容易合成的纳米材料,尤其是其优异的催化活性,可以作为水环境的净化处理,受到了人们的广泛关注,所以,纳米TiO_2是目前最合适的催化剂之一。但是,由于实验室所制备的TiO_2可能会有颗粒分布不均,分散性较差,易团聚,而且TiO_2是一种半导体复合物,其电子-空穴对极容易复合,其禁带宽度大,只能用紫外光激发,不能有效地利用可见光和太阳能。这些都会导致TiO_2的催化效率降低。许多研究指出可以添加金属或非金属元素对TiO_2做出改性处理。本文主要通过溶胶-凝胶法,以钛酸丁酯为原料,制备了纯TiO_2光催化剂。利用亲水性多壁碳纳米管(oCNTs)对纳米TiO_2进行了改性处理,制备了羧基化碳纳米管负载纳米二氧化钛(TiO_2/oCNTs)复合光催化剂,并对TiO_2/oCNTs复合光催化剂进行了催化性能的研究和分析;通过过渡金属Fe对TiO_2/oCNTs复合光催化剂进行了掺杂研究分析。而且,通过TiO_2光催化剂、TiO_2/oCNTs复合光催化剂和Fe-TiO_2/oCNTs复合光催化剂对模拟污染物甲基橙的光催化降解效果评价了光催化剂催化活性的高低。(1)羧基化的多壁碳纳米管经过超声震荡处理后,比原始碳管在有机溶剂中的分散性要更好,团聚的较少,互相缠结也比较少,易于与钛酸丁酯结合;(2)通过 TEM、XRD、XPS、FT-IR、UV-vis 等表征手段对 oCNTs 和TiO_2/oCNTs进行测试分析,证明oCNTs是官能化的,并且oCNTs的表面负载上了纳米TiO_2粒子;(3)纳米TiO_2光催化剂对模拟污染物甲基橙的光催化降解效果的评价,证实了 TiO_2光催化剂降解甲基橙的最佳条件是:纳米TiO_2的煅烧温度为450℃,TiO_2光催化剂的浓度为0.8 g/L,甲基橙溶液的浓度为20mg/L,甲基橙溶液的pH值为3.64;(4)oCNTs相对于纳米TiO_2为3wt%,可以有效地提高TiO_2/oCNTs复合材料的光催化性能,而oCNTs在低含量时,在一定程度上促进纳米TiO_2的负载,提升TiO_2/oCNTs复合材料光催化性能;oCNTs高含量时,会因团聚缠结,降低TiO_2/oCNTs复合材料的光催化活性。其中,TiO_2/oCNTs复合材料的光催化利用率可达到95%;(5)通过Fe~(3+)对TiO_2/oCNTs复合材料的掺杂改性,发现Fe~(3+)可以置换TiO_2中的Ti4+,进而破坏TiO_2的晶格结构,光照下减少TiO_2中电子—空穴对的复合,提高复合材料的光催化活性。Fe~(3+)的最佳添加量为6wt%。
[Abstract]:Titanium dioxide is a kind of safe and non-toxic, high chemical activity, low cost, easy to synthesize nanomaterials, especially its excellent catalytic activity, which can be used as purification treatment of water environment. Nanocrystalline TiO_2 is one of the most suitable catalysts at present. However, the TiO_2 prepared in the laboratory may have uneven particle distribution, poor dispersion and easy agglomeration. Moreover, TiO_2 is a semiconductor complex, and its electron-hole pair is very easy to recombine. The band gap is so wide that it can only be excited by ultraviolet light. It is pointed out that TiO_2 can be modified by adding metal or non-metallic elements. Pure TiO_2 photocatalyst was prepared by using butyl titanate as raw material, and modified by hydrophilic multiwalled carbon nanotubes (MwCNTs) to prepare carboxylated carbon nanotubes (CNTs) supported nano-TiO _ 2 / TIO _ 2 / TIO _ 2 composite photocatalyst. The catalytic performance of TiO_2/oCNTs composite photocatalyst was studied and analyzed, and the doping of TiO_2/oCNTs composite photocatalyst was studied by transition metal Fe. The photocatalytic degradation of methyl orange, a simulated pollutant, was evaluated by the photocatalytic degradation of TiO-2 / TiOCNTs composite photocatalyst and Fe-TiO_2/oCNTs photocatalyst. The carboxylated multi-walled carbon nanotubes (MWCNTs) were treated by ultrasonic shock. The dispersity of carbon tubes in organic solvents is better than that of original carbon tubes, the agglomeration is less, the entanglement is less, and it is easy to bind with butyl titanate. (2) oCNTs and TiO_2/oCNTs are characterized by means of TEM, XRDX, XPSN, FT-IR, UV-vis, and so on. The results show that oCNTs is functionalized. The photocatalytic degradation of methyl orange, a simulated pollutant, was evaluated by nanometer TiO_2 photocatalyst supported on the surface of oCNTs. The optimum conditions for degradation of methyl orange by TiO_2 photocatalyst are as follows: the calcination temperature of nanometer TiO_2 is 450 鈩，

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