钒酸铁、钼酸铁和钒酸镉掺杂石墨相氮化碳材料的光催化性能研究

发布时间：2019-02-11 09:42

【摘要】：自上世纪七十年代以来,半导体光催化技术备受科学研究者的青睐。出于充分利用太阳能的需要,科学家把可见光响应光催化剂材料的研发作为光催化材料发展的首要问题。g-C3N4是近年来报道一种新型的有机聚合物半导体,具有可响应可见光,化学与热稳定性好、无毒且制备简易等优点,受到全世界科研究人员的关注,应用前景广阔。本论文主要是以g-C3N4基础,通过钒酸铁、钼酸铁和钒酸镉的修饰来改性g-C3N4,从而获得了三种高效的可见光响应光催化剂。首先,采用简单的水热和研磨焙烧法制备出可响应可见光的FeVO4/g-C3N4复合型光催化剂。通过对复合催化剂进行一系列的表征,得出其光催化反应的机理。由诸多表征的结果我们可以得到结论,即催化剂活性的增加的根本原因是FeVO4/g-C3N4之间形成了异质结,抑制光生电子-空穴对的复合。而且,FeVO4/g-C3N4掺杂含量是影响催化剂活性的一个重要因素,其中当FeVO4实际含量为5.0wt%时,该复合催化剂的催化活性最高。其次,采用研磨-焙烧法制备了g-C3N4/Fe2(MoO4)3复合相催化剂,该催化剂对可见光有很好的响应,可吸收波长小于560nm的可见光。在可见光下表现出极好的催化效果,其中10.6wt%g-C3N4/Fe2(MoO4)3的催化效果最佳,根本原因是g-C3N4和Fe2(MoO4)3具有匹配的能带结构,可构成异质结结构提高了电子和空穴的分离效率,延长了载流子的寿命,从而提高了催化剂活性。最后,采用同样的方法制备了CdV2O6/g-C3N4复合型光催化剂,考察了该催化剂对罗丹明B在可见光照射下降解性能。通过X射线粉末衍射(XRD),N2物理吸附(BET),傅里叶变换红外光谱(FT-IR),紫外可见漫反射(UV-vis DRS),热重(TG),扫描电子显微镜(SEM),透射电子显微镜(TEM),化学需氧量(COD)测定等技术对催化剂进行了表征,对该催化剂的性质、结构、形貌和光催化活性的进行研究。结果表明,该催化剂催化活性高和稳定性好,具有较广阔的前景。
[Abstract]:Since the 1970s, semiconductor photocatalysis technology has been favored by scientific researchers. In order to make full use of solar energy, scientists regard the research and development of visible light responsive photocatalyst materials as the most important problem in the development of photocatalytic materials. G-C3N4 is a new type of organic polymer semiconductor reported in recent years. It has the advantages of visible light, good chemical and thermal stability, nontoxic and simple preparation, and has attracted the attention of researchers all over the world, and has a broad application prospect. In this paper, based on g-C3N4, three kinds of high efficient visible light responsive photocatalysts were obtained by modifying g-C _ 3N _ 4 with the modification of ferrovanadate, ferromolybdate and cadmium vanadate. Firstly, a simple hydrothermal and grinding roasting method was used to prepare FeVO4/g-C3N4 composite photocatalyst which can respond to visible light. The mechanism of photocatalytic reaction was obtained by a series of characterization of the composite catalyst. From the results of many characterizations we can draw a conclusion that the fundamental reason for the increase of catalyst activity is the formation of heterojunctions between FeVO4/g-C3N4 and the inhibition of photogenerated electron-hole pairs. Moreover, the doping content of FeVO4/g-C3N4 is an important factor affecting the activity of the catalyst. When the actual content of FeVO4 is 5.0 wt%, the catalytic activity of the composite catalyst is the highest. Secondly, g-C3N4/Fe2 (MoO4) 3 composite phase catalyst was prepared by grinding and calcination method. The catalyst has a good response to visible light and can absorb visible light with a wavelength less than 560nm. 10.6wt%g-C3N4/Fe2 (MoO4) 3 has the best catalytic effect under visible light. The fundamental reason is that g-C3N4 and Fe2 (MoO4) 3 have matched band structure. The structure of heterojunction improves the efficiency of electron and hole separation, prolongs the lifetime of carriers, and improves the activity of catalyst. Finally, the CdV2O6/g-C3N4 composite photocatalyst was prepared by the same method, and the degradation performance of Rhodamine B under visible light irradiation was investigated. (BET), Fourier transform infrared spectroscopy (FT-IR), UV-vis DRS), thermogravimetric (TG), scanning electron microscope (SEM),) and X-ray powder diffraction (XRD), N2) physical adsorption on (BET), The catalytic properties, structure, morphology and photocatalytic activity of the catalyst were investigated by transmission electron microscopy (TEM), (TEM), chemical oxygen demand (COD) and other techniques. The results show that the catalyst has high catalytic activity and good stability and has a broad prospect.
【学位授予单位】：浙江师范大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O643.36;O644.1

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