二氧化钛纳米复合材料的制备及其光催化性能研究
发布时间：2019-01-29 21:24
【摘要】：随着现代社会的不断发展,环境污染问题变得越来越严重。光催化技术作为一种新型污染物降解技术,其能耗低、使用范围广,成为解决环境污染问题的有效方法。二氧化钛是一种广泛使用的光催化材料,拥有无毒、无污染、价格低廉、催化效率高等优点。然而理论研究发现二氧化钛自身存在两个严重缺陷,一是光生电子-空穴对复合速率过快;二是在可见光范围内没有响应(禁带宽度为3.2 eV)。为了更好的利用二氧化钛的光催化性能,科研人员设计了一系列改进方法,包括表面修饰等方法。本论文通过降低二氧化钛光生电子-空穴复合速率、提高二氧化钛比表面积和降低二氧化钛带隙能等方法,设计出三种新型二氧化钛复合材料,并通过XRD、Raman、SEM、TEM、Uv-Vis和XPS等测试对材料的晶格结构、微观形态、质构特性、带隙能、表面化学状态等进行表征;通过光催化降解、光电流测试对材料光催化性能进行表征,其主要研究内容如下:(1)还原氧化石墨烯-二氧化钛复合光催化剂:通过水热法将氧化石墨烯与二氧化钛纳米颗粒(NP)相复合,制备得到纳米尺寸的石墨烯-二氧化钛复合物。石墨烯与二氧化钛纳米颗粒的界面效应能降低催化剂带隙能;同时石墨烯的高导电性能提高催化剂中电子转移速率。在所制备的还原氧化石墨烯-二氧化钛复合物中,25%还原氧化石墨烯-二氧化钛复合物拥有最佳的光催化性能,其吸附有机物能力和光降解有机物能力都超过其它复合物催化剂,并且拥有高循环利用性能,循环降解甲基橙30次后降解率仍然能达到93%。(2)二氧化钛纳米颗粒-二氧化铈纳米棒复合光催化剂:采用合成的大比表面积二氧化铈纳米棒,通过简单的水热法将二氧化钛纳米颗粒负载在二氧化铈纳米棒上,制备了一种新型二氧化钛复合光催化剂。二氧化铈纳米棒的大比表面积提高催化剂对于污染物的吸附能力,同时二氧化铈纳米棒与二氧化钛纳米颗粒之间的界面效应能有效降低催化剂带隙能。在所制备的二氧化钛纳米颗粒-二氧化铈纳米棒复合材料中,30%二氧化钛纳米颗粒-二氧化铈纳米棒复合物拥有最佳的光催化性能,其光降解有机物能力超过其它复合物催化剂。(3)硫化镉纳米颗粒-二氧化钛纳米棒复合物光催化剂:采用制备的硫化镉纳米颗粒,通过简单的水热法将硫化镉纳米颗粒负载到二氧化钛纳米棒表面,制备出了一种新型二氧化钛复合催化剂。硫化镉纳米颗粒较低的带隙能(2.42 eV)能提高催化剂对于可见光的响应范围,同时利用硫化镉纳米颗粒较低的尺寸可提高催化剂吸附污染物能力。在所制备的硫化镉纳米颗粒-二氧化钛纳米棒复合材料中,40%硫化镉纳米颗粒-二氧化钛纳米棒复合物拥有最佳的光催化性能,其光降解有机物能力超过其它复合物催化剂,在太阳光下光催化性能比纯品二氧化钛光催化性能提高了2倍以上。
[Abstract]:With the development of modern society, the problem of environmental pollution becomes more and more serious. Photocatalytic technology, as a new pollutant degradation technology, has low energy consumption and wide range of application, so it has become an effective method to solve the problem of environmental pollution. Titanium dioxide is a widely used photocatalytic material, which has the advantages of non-toxic, pollution-free, low price and high catalytic efficiency. However, the theoretical study found that there are two serious defects in titanium dioxide itself, one is that the photoelectron / hole pair recombination rate is too fast, and the other is that there is no response in the visible light range (bandgap is 3.2 eV). In order to make better use of the photocatalytic properties of titanium dioxide, researchers have designed a series of improved methods, including surface modification. In this paper, three new titanium dioxide composites were designed by reducing the photogenerated electron-hole recombination rate, increasing the specific surface area of titanium dioxide and reducing the band gap energy of titanium dioxide. The lattice structure, microstructure, texture, band gap energy and surface chemical state were characterized by Uv-Vis and XPS. The photocatalytic properties of the materials were characterized by photocatalytic degradation and photocurrent test. The main research contents are as follows: (1) reduced graphene oxide / TIO _ 2 composite photocatalyst: graphene oxide and TIO _ 2 nanoparticles (NP) phase were synthesized by hydrothermal method. Nano-sized graphene-titanium dioxide composites were prepared. The interfacial effect between graphene and TIO _ 2 nanoparticles can reduce the band gap energy of the catalyst, and the high conductivity of graphene can improve the electron transfer rate in the catalyst. The 25% reductive graphene oxide titania composite has the best photocatalytic activity among the reduced graphene oxide titanium dioxide complexes. The ability of adsorption and photodegradation of organic compounds is higher than that of other complex catalysts, and has high recycling performance. The degradation rate of methyl orange can still reach 933 after 30 cycles. (2) Titanium dioxide nanoparticles and cerium dioxide nanorods composite photocatalyst: the synthesized cerium oxide nanorods with large specific surface area, A new type of TIO _ 2 composite photocatalyst was prepared by a simple hydrothermal method with TIO _ 2 nanoparticles loaded on cerium oxide nanorods. The large specific surface area of cerium oxide nanorods improves the adsorption ability of the catalyst to pollutants, and the interfacial effect between cerium oxide nanorods and titanium dioxide nanoparticles can effectively reduce the band gap energy of the catalyst. Among the prepared TIO _ 2 nanoparticles and cerium dioxide nanorods composites, 30% TIO _ 2 nanoparticles and cerium dioxide nanorods composites have the best photocatalytic properties. The photodegradation of organic compounds is superior to that of other complex catalysts. (3) cadmium sulphide nanoparticles-titanium dioxide nanorods composite photocatalysts: the preparation of cadmium sulfide nanoparticles, A new titanium dioxide composite catalyst was prepared by simply loading cadmium sulfide nanoparticles onto the surface of titanium dioxide nanorods. The low band gap energy (2.42 eV) of cadmium sulfide nanoparticles can increase the response range of the catalyst to visible light, and the adsorption ability of the catalyst can be improved by using the lower size of cadmium sulfide nanoparticles. Among the prepared cadmium sulfide nanoparticles and titanium dioxide nanorods composites, 40% cadmium sulfide nanocrystalline titania nanorods composite has the best photocatalytic performance, and its photodegradation ability is superior to that of other composite catalysts. The photocatalytic performance of pure titanium dioxide is more than 2 times higher than that of pure titanium dioxide under sunlight.
【学位授予单位】：南昌航空大学
【学位级别】：硕士
【学位授予年份】：2018
【分类号】：TB33;O643.36
本文编号：2417876
[Abstract]:With the development of modern society, the problem of environmental pollution becomes more and more serious. Photocatalytic technology, as a new pollutant degradation technology, has low energy consumption and wide range of application, so it has become an effective method to solve the problem of environmental pollution. Titanium dioxide is a widely used photocatalytic material, which has the advantages of non-toxic, pollution-free, low price and high catalytic efficiency. However, the theoretical study found that there are two serious defects in titanium dioxide itself, one is that the photoelectron / hole pair recombination rate is too fast, and the other is that there is no response in the visible light range (bandgap is 3.2 eV). In order to make better use of the photocatalytic properties of titanium dioxide, researchers have designed a series of improved methods, including surface modification. In this paper, three new titanium dioxide composites were designed by reducing the photogenerated electron-hole recombination rate, increasing the specific surface area of titanium dioxide and reducing the band gap energy of titanium dioxide. The lattice structure, microstructure, texture, band gap energy and surface chemical state were characterized by Uv-Vis and XPS. The photocatalytic properties of the materials were characterized by photocatalytic degradation and photocurrent test. The main research contents are as follows: (1) reduced graphene oxide / TIO _ 2 composite photocatalyst: graphene oxide and TIO _ 2 nanoparticles (NP) phase were synthesized by hydrothermal method. Nano-sized graphene-titanium dioxide composites were prepared. The interfacial effect between graphene and TIO _ 2 nanoparticles can reduce the band gap energy of the catalyst, and the high conductivity of graphene can improve the electron transfer rate in the catalyst. The 25% reductive graphene oxide titania composite has the best photocatalytic activity among the reduced graphene oxide titanium dioxide complexes. The ability of adsorption and photodegradation of organic compounds is higher than that of other complex catalysts, and has high recycling performance. The degradation rate of methyl orange can still reach 933 after 30 cycles. (2) Titanium dioxide nanoparticles and cerium dioxide nanorods composite photocatalyst: the synthesized cerium oxide nanorods with large specific surface area, A new type of TIO _ 2 composite photocatalyst was prepared by a simple hydrothermal method with TIO _ 2 nanoparticles loaded on cerium oxide nanorods. The large specific surface area of cerium oxide nanorods improves the adsorption ability of the catalyst to pollutants, and the interfacial effect between cerium oxide nanorods and titanium dioxide nanoparticles can effectively reduce the band gap energy of the catalyst. Among the prepared TIO _ 2 nanoparticles and cerium dioxide nanorods composites, 30% TIO _ 2 nanoparticles and cerium dioxide nanorods composites have the best photocatalytic properties. The photodegradation of organic compounds is superior to that of other complex catalysts. (3) cadmium sulphide nanoparticles-titanium dioxide nanorods composite photocatalysts: the preparation of cadmium sulfide nanoparticles, A new titanium dioxide composite catalyst was prepared by simply loading cadmium sulfide nanoparticles onto the surface of titanium dioxide nanorods. The low band gap energy (2.42 eV) of cadmium sulfide nanoparticles can increase the response range of the catalyst to visible light, and the adsorption ability of the catalyst can be improved by using the lower size of cadmium sulfide nanoparticles. Among the prepared cadmium sulfide nanoparticles and titanium dioxide nanorods composites, 40% cadmium sulfide nanocrystalline titania nanorods composite has the best photocatalytic performance, and its photodegradation ability is superior to that of other composite catalysts. The photocatalytic performance of pure titanium dioxide is more than 2 times higher than that of pure titanium dioxide under sunlight.
【学位授予单位】：南昌航空大学
【学位级别】：硕士
【学位授予年份】：2018
【分类号】：TB33;O643.36
【参考文献】
相关期刊论文 前1条
1 王建强,辛柏福,于海涛,谢玉涛,赵冰,付宏刚;二氧化钛系列光催化剂的拉曼光谱[J];高等学校化学学报;2003年07期
，本文编号：2417876
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