石墨相氮化碳复合材料的制备及光降解性能研究

发布时间：2018-04-01 14:38

  本文选题：静电纺丝　切入点：ZnO/g-C_3N_4(s)复合纤维　出处：《南京理工大学》2017年硕士论文

【摘要】：石墨相氮化碳纳米片是近几年来受到大量关注的材料之一,其拥有许多优良的性质,比如与石墨烯类似的特殊的片状结构,适合可见光吸收的带隙,无金属性质,非常好的稳定性等,在许多方面展现出潜在的应用价值,但同时又由于自身结构和性质的限制,在光催化降解领域依然存在一些抑制其应用的问题,比如对太阳光整体吸收能力弱、光生电子-空穴易复合、纳米片易发生团聚等问题。鉴于此,本文对g-C_3N_4(s)进行复合改性研究,制备得到 ZnO/g-C_3N_4(s)、C/g-C_3N_4(s)、TiO_2/g-C_3N_4(s)和 N-TiO_2/g-C_3N_4(s)纳米复合纤维,采用FTIR、TGA、光学显微镜、SEM、XRD、UV-VISDRS、接触角测量仪、光催化反应仪和紫外可见分光光度计等表征手段测试了复合材料的组成、结构和形貌以及光催化性能。首先,在PVP浓度为12wt%且含Zn(Ac)_2的纺丝液体系中,掺入少量g-C_3N_4(s)进行静电混纺,得到PVP/Zn(Ac)_2/g-C_3N_4(s)复合纤维膜,纤维膜经高温煅烧后,FTIR、TGA和XRD谱图均证明主要物质为g-C_3N_4和ZnO,SEM照片观察到g-C_3N_4(s)均匀地混入ZnO纤维的表面和内部,光催化实验表明ZnO/g-C_3N_4(s)复合纤维具有比单一的ZnO和g-C_3N_4(s)更优异的光催化活性。其次,采用静电纺丝方法制得PAN纤维膜,再通过悬滴浸入法结合高温碳化过程,成功将g-C_3N_4(s)负载到碳纤维的表面。FTIR和XRD谱图均显示出g-C_3N_4(s)和C的存在,SEM照片清晰地观察到g-C_3N_4(s)在C纤维表面的负载。光催化实验结果表明,不同碳化温度条件下分别得到的C/g-C_3N_4(s)复合纤维均具有很好的吸附性能,600℃条件下吸附性能最强,但500℃条件下得到的复合纤维光催化性能最好,与单一的g-C_3N_4(s)相比,活性明显提高。再次,采用静电纺丝法结合高温煅烧过程合成出TiO_2纤维,再通过单层分散法结合热处理过程,成功制备出TiO_2/g-C_3N_4(s)纳米复合纤维。FTIR、TGA和XRD谱图显示出复合材料由g-C_3N_4(s)和TiO_2组成,SEM照片显示g-C_3N_4(s)紧密粘附在TiO_2短纤维上。紫外-可见漫反射曲线证明复合材料具有更好的吸光性能,纳米复合纤维相对于纯的TiO_2和g-C_3N_4(s)而言模拟太阳光光降解性能显著提高,可见光光降解性能也有略微提高。最后,以三聚氰胺为氮源和造孔剂,采用静电纺丝法结合高温煅烧过程合成出N-TiO_2纤维,再通过单层分散法结合热处理过程,成功制备出N-TiO_2/g-C_3N_4(s)纳米复合纤维。FTIR、TGA和XRD谱图显示出复合材料由g-C_3N_4(s)和N-TiO_2组成,SEM照片显示N-TiO_2呈多孔短纤维结构,并且与g-C_3N_4(s)紧密结合在一起。光催化实验结果表明,N-TiO_2/g-C_3N_4(s)纳米复合纤维相对于纯的N-TiO_2和g-C_3N_4(s)而言模拟太阳光光降解性能进一步显著提高,可见光光降解性能也明显提高,N-TiO_2纤维也表现出一定的可见光光降解性能,且光降解性能相对于TiO_2而言有一定的提高,说明多孔结构、N掺杂和半导体复合,综合改善了光催化性能。
[Abstract]:Graphite-phase carbon nitride nanocrystals are one of the most important materials in recent years. They have many excellent properties, such as the special flake structure similar to graphene, the band gap suitable for visible light absorption, and the metal-free properties.Very good stability shows potential application value in many aspects, but at the same time, due to the limitations of its own structure and properties, there are still some problems in the field of photocatalytic degradation that inhibit its application.For example, the whole absorption of sunlight is weak, photogenerated electrons and holes are easy to recombine, and nanochips are easy to reunite.The composition, structure, morphology and photocatalytic properties of the composites were measured by photocatalytic reaction apparatus and UV-Vis spectrophotometer.First of all, in the spinning solution system with PVP concentration of 12 wt% and containing Zn(Ac)_2, a small amount of g-C _ 3N _ 4 / S) was mixed by electrostatic mixing, and then the PVP / Zn / Zn / PVP / PVP / Zn / Zn / C _ 3 / C _ 3 / C _ 3N _ 4 / S composite fiber membrane was obtained by adding a small amount of g-C _ 3N _ 4 / S) into the spinning liquid system containing Zn(Ac)_2.Secondly, the PAN fiber membrane was prepared by electrostatic spinning method, and then the suspension drop immersion method was used to combine the high temperature carbonization process.The surface of the carbon fiber was successfully loaded with g-C _ 3N _ 4s). FTIR and XRD spectra showed that g-C _ 3N _ 4s) and C _ () were clearly observed on the surface of the C fiber by the SEM photos of g-C _ 3N _ 4s).The results of photocatalytic experiments showed that the C / g-C _ 3N _ 3N _ 4 / S composite fibers obtained at different carbonization temperatures had the strongest adsorption performance at 600 鈩，

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