宽光谱响应钙钛矿型光催化材料的研究

发布时间：2019-01-11 08:25

【摘要】：近年来,环境污染日益严重,光催化技术作为一种环保的新技术,在治理环境方面有诸多优点。钙钛矿型光催化材料因其特殊的晶体结构、热稳定性和化学稳定性而成为光催化技术领域研究的热点。本课题正是基于钙钛矿型光催化材料良好的应用前景,展开对KSr2Nb3O10和SrTiO_3的改性研究,采用XRD、SEM、TEM、EDS、DRS、XPS等表征方法来分析材料的物化性质,并通过甲基橙的降解实验来研究光催化材料的活性,主要内容如下:1)高温固相法制备钙钛矿型光催化材料KSr2Nb3O10,对KSr2Nb3O10进行换酸改性后获得HSr_2Nb_3O_(10)。与KSr2Nb3O10相比,HSr_2Nb_3O_(10)的粒径大小和光吸收能力几乎不变,部分层状结构出现缝隙,光催化活性显著提升。接着对HSr_2Nb_3O_(10)进行正己胺柱撑后获得HSr_2Nb_3O_(10)/nC6H13NH2,块状颗粒的层间结构被柱撑开成片状,在可见光照射60 min后,甲基橙的降解达到77.9%,其光催化性能远优于KSr2Nb3O10和HSr_2Nb_3O_(10)。此外,还对KSr2Nb3O10进行Cr,Er,La离子掺杂改性实验,掺杂后又进一步进行换酸和柱撑改性,实验结果表明Cr掺杂的HSr_2Nb_3O_(10)/nC6H13NH2催化活性最高。2)固相法制备钙钛矿型光催化材料SrTiO_3,在此基础上与掺杂La的WO_3复合,水热法制备复合物La-WO_3/SrTiO_3,并通过调节复合物中SrTiO_3和La-WO_3的摩尔比来确定光催化活性最佳的比例。实验结果表明SrTiO_3和La-WO_3紧密结合形成异质结结构,禁带宽度减小,对可见光的吸收能力增强,光催化活性显著提高,其中La-WO_3/SrTiO_3-50%的光催化效果最佳,在可见光照射60 min后甲基橙完全降解。3)固相法制备钙钛矿型光催化材料SrTiO_3,在此基础上进一步与水热法制备的Bi2O_3光催化剂形成复合物SrTiO_3/Bi2O_3,通过调节SrTiO_3和Bi2O_3之间的摩尔比来探讨不同比例下复合物SrTiO_3/Bi2O_3的光催化活性高低。实验结果表明Bi2O_3与SrTiO_3紧密结合形成异质结,禁带宽度减小,对可见光的吸收能力提高,复合后的光催化活性明显优于单质Bi2O_3和SrTiO_3,其中SrTiO_3/Bi2O_3-150%的光催化效果最佳,可见光照射45 min后甲基橙完全降解。
[Abstract]:In recent years, environmental pollution is becoming more and more serious. Photocatalytic technology, as a new environmental protection technology, has many advantages in environmental control. Perovskite photocatalytic materials have become a hotspot in the field of photocatalysis due to their special crystal structure, thermal stability and chemical stability. Based on the good application prospect of perovskite photocatalytic materials, the modification of KSr2Nb3O10 and SrTiO_3 was studied, and the physicochemical properties of the materials were analyzed by XRD,SEM,TEM,EDS,DRS,XPS. The main contents are as follows: 1) perovskite photocatalytic material KSr2Nb3O10, was prepared by high temperature solid state method to modify KSr2Nb3O10 by acid exchange. HSr_2Nb_3O_ (10) was obtained. Compared with KSr2Nb3O10, the size of HSr_2Nb_3O_ (10) and the photoabsorption capacity of HSr_2Nb_3O_ (10) were almost unchanged, and some of the layered structure appeared cracks, thus the photocatalytic activity of HSr_2Nb_3O_ (10) was improved significantly. The interlaminar structure of HSr_2Nb_3O_ (10) / nC6H13NH2, bulk particles was then supported with n-hexylamine column for HSr_2Nb_3O_ (10). The interlaminar structure of HSr_2Nb_3O_ (10) / nC6H13NH2, particles was flake. After 60 min of visible light irradiation, the degradation of methyl orange reached 77.9%. Its photocatalytic performance is much better than that of KSr2Nb3O10 and HSr_2Nb_3O_ (10). In addition, the Cr,Er,La ion doping modification experiment was carried out on KSr2Nb3O10, and further acid exchange and pillared modification were carried out after doping. The experimental results show that Cr doped HSr_2Nb_3O_ (10) / nC6H13NH2 has the highest catalytic activity. 2) the perovskite-type photocatalytic material SrTiO_3, is prepared by solid phase method. On this basis, SrTiO_3, is compounded with La doped WO_3. La-WO_3/SrTiO_3, was prepared by hydrothermal method and the optimum ratio of photocatalytic activity was determined by adjusting the molar ratio of SrTiO_3 and La-WO_3 in the complex. The experimental results show that SrTiO_3 and La-WO_3 combine closely to form heterojunction structure, the band gap decreases, the absorption ability of visible light is enhanced, and the photocatalytic activity is improved significantly. The photocatalytic effect of La-WO_3/SrTiO_3-50% was the best, and the methyl orange was completely degraded after 60 min of visible light irradiation. 3) the perovskite photocatalytic material SrTiO_3, was prepared by solid phase method. On this basis, the complex SrTiO_3/Bi2O_3, was further formed with Bi2O_3 photocatalyst prepared by hydrothermal method. The photocatalytic activity of the complex SrTiO_3/Bi2O_3 was studied by adjusting the molar ratio between SrTiO_3 and Bi2O_3. The experimental results show that Bi2O_3 binds closely with SrTiO_3 to form heterojunction, the band gap decreases, and the absorption ability of visible light is improved. The photocatalytic activity of the composite is obviously superior to that of Bi2O_3 and SrTiO_3,. The photocatalytic effect of SrTiO_3/Bi2O_3-150% was the best, and methyl orange was completely degraded by visible light irradiation for 45 min.
【学位授予单位】：华侨大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36;O644.1

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