固相法制备氧化物催化剂及其催化甲苯完全氧化

发布时间：2018-06-18 21:18

本文选题：室温固相反应 + 高能球磨法　；参考：《复旦大学》2011年硕士论文

【摘要】：随着政府、社会和公众对环境保护的要求越来越高,如何处理工业生产尾气中的挥发性有机物(VOCs)成为环保方面研究的热点。催化燃烧技术作为最有效的处理有机废气的方法受到了研究者的重视,开发高效、廉价催化剂是相关研究亟待解决的一个问题。贵金属催化剂虽然活性好,但是高昂的价格大大限制了它的应用,过渡金属氧化物催化剂作为贵金属催化剂的替代物引起了大家的关注。本文从改进催化剂制备方法以提高催化剂活性的角度出发,研究了简单、高效、低能耗的固相法在氧化物催化剂的制备中的应用,我们通过室温固相法制备了Co3O4、CeO2、Mn2O3,通过高能球磨法制备制备了铜钴复合氧化物,在催化甲苯完全氧化时均表现出很好的活性。具体如下：1、固相法制备四氧化钴催化剂及其催化甲苯完全氧化Co3O4是被广泛应用的催化剂,在催化氧化、电化学、传感器等方面有重要的应用。我们采用室温固相反应制备了Co3O4的前驱体,经过一定温度的焙烧,得到了纳米Co3O4,本方法过程简单,能耗低,环境友好。与常规的沉淀法、柠檬酸络合-燃烧法相比,固相法制备得到的Co3O4催化剂粒径小、表面缺陷较多、表面Co-O键较弱、表面吸附氧丰富,具有更好的活化氧的能力,表现出更好的催化甲苯完全氧化活性。催化剂前驱体的焙烧温度对催化剂的活性有很大影响,400℃C焙烧时催化剂的性能最优。对催化剂进行了60小时的老化测试,在230℃甲苯的转化率始终保持在95%以上。2、固相法制备氧化铈催化剂及其催化甲苯完全氧化氧化铈在催化中有非常广泛的应用,既可以作为催化剂助剂,也可以作为主要的活性组分,还是很好的催化剂载体。我们采用固相法制备的纳米氧化铈在催化甲苯的完全氧化反应中表现出了非常好的活性,BET、XRD、Raman、SEM、H2-TPR等表征表明,固相法制备得到的Ce02催化剂粒径小、表面缺陷较多、表面吸附氧丰富,活化氧的能力强。前驱体的焙烧温度对催化剂的活性有很大影响,500℃焙烧时催化剂的性能最优。对催化剂进行的100小时的老化表明,在215℃C甲苯的转化率始终保持在95%以上。3、固相法制备氧化锰催化剂及其催化甲苯完全氧化我们采用与前面相同的固相法制备得到了Mn203催化剂,与柠檬酸络合-燃烧法和沉淀法制备的锰氧化物相比,固相法制备得到的Mn203催化剂粒径小、表面缺陷较多、低温氧化还原性能好,具有更好的活化氧的能力,所以催化甲苯完全氧化的能力更强。同时,催化剂前驱体的焙烧温度对锰催化剂的活性有很大影响,3500C焙烧时催化剂的性能最优,同时前驱体已经分解完全,在246℃就可以达到95%的甲苯转化率。4、高能球磨法制备铜钴复合氧化物及其催化甲苯完全氧化高能球磨法利用球磨机的高速震动和转动使硬球对原料进行强烈的撞击、研磨和搅拌,从而使粉末颗粒产生塑性形变、颗粒内产生大量的缺陷,在颗粒的接触面达到局部高温诱发化学反应发生,这样得到的复合氧化物即处于纳米范畴之内,同时又在表面富集有很多缺陷位,为反应提供了活性中心。我们通过高能球磨法制备得到铜钴复合氧化物催化剂,与传统的共沉淀法相比,高能球磨法制备的催化剂活性更好,6小时碾磨制备的催化剂,在2220C时甲苯的转化率就可以达到50%,230℃时甲苯的转化率超过95%。通过表征表明高能球磨法制备的催化剂晶粒较小、表面缺陷丰富,这都有利于甲苯的完全氧化的反应。稳定性测试表明,固相法制备的催化剂的抗老化能力也更强。
[Abstract]:With the government, society and the public are becoming more and more demanding for environmental protection, how to deal with volatile organic compounds (VOCs) in industrial production exhaust has become a hot topic in environmental protection research. As the most effective method of treating organic waste gas, catalytic combustion technology has been re viewed by researchers. It is urgent to develop high efficiency and cheap catalysts. A solution to the problem. Although the noble metal catalyst has good activity, the high price greatly restricts its application. The transition metal oxide catalyst as a substitute for the noble metal catalyst has aroused the attention of everyone. This paper is simple, efficient and low in the view of improving the catalyst preparation method to improve the activity of the catalyst. The application of energy consumption solid phase method in the preparation of oxide catalysts, Co3O4, CeO2, Mn2O3 were prepared by solid-state method at room temperature. The co oxides of copper and cobalt were prepared by high energy ball milling, and they all showed good activity during the complete oxidation of toluene. 1, the solid phase method was used to prepare cobalt four catalyst and its catalytic armor. Benzene complete oxidation Co3O4 is a widely used catalyst. It has important applications in catalytic oxidation, electrochemistry, sensor and so on. We prepared the precursor of Co3O4 by solid state reaction at room temperature. After a certain temperature roasting, the nano Co3O4 was obtained. The process is simple, energy consumption is low, and the environment is friendly. Compared with the combined combustion method, the Co3O4 catalyst prepared by the solid-phase method has small particle size, more surface defects, weak surface Co-O bond, rich oxygen adsorption on the surface, better ability of activating oxygen, and better catalytic activity of toluene. The calcination temperature of the precursor catalyst has a great influence on the activity of the catalyst, when the catalyst is calcined at 400 C for C The performance of the catalyst is the best. The catalyst has been tested for 60 hours, and the conversion rate of toluene at 230 centigrade remains above 95%.2. The solid phase preparation of cerium oxide catalyst and its catalytic toluene oxide fully oxidize cerium oxide are widely used in the catalysis. It can be used as a catalyst agent and as the main active group. BET, XRD, Raman, SEM, H2-TPR and so on showed that the particle size of the Ce02 catalyst prepared by the solid phase method was small, the surface defects were more, the surface adsorbed oxygen was abundant and the ability of activating oxygen was strong. The calcination temperature of the precursor has a great influence on the activity of the catalyst, and the performance of the catalyst is the best when roasting at 500 C. The 100 hour aging of the catalyst shows that the conversion rate of toluene at 215 C is kept above 95%. The solid phase method for the preparation of manganese oxide catalyst and the complete oxidation of toluene we use the same solid as in front of the catalyst. The Mn203 catalyst was prepared by phase method. Compared with the manganese oxides prepared by the citric acid complex combustion method and the precipitation method, the Mn203 catalyst prepared by the solid phase method has small particle size, more surface defects, better oxidation reduction performance at low temperature and better ability of activating oxygen, so the ability to oxidize toluene to complete oxidation is stronger. At the same time, before the catalyst, the catalyst is more effective. The calcination temperature of the drive has a great influence on the activity of the manganese catalyst. At the same time, the performance of the catalyst is the best when 3500C is roasted. At the same time, the precursor has been completely decomposed, and the conversion rate of toluene can be up to 95% at 246 degrees C. The high energy ball milling method is used to prepare the copper cobalt complex oxide and the high velocity vibration of the complete oxidation of toluene by high energy ball milling. The hard ball has a strong impact on the raw material, grinding and stirring, so that the powder particles are plastic deformation, a large number of defects are produced in the particles, and the chemical reaction occurs in the contact surface of the particles. The compound oxide is in the nanometer category, and there are many defects on the surface. The catalyst was prepared by high energy ball milling. Compared with the traditional coprecipitation method, the activity of the catalyst prepared by high energy ball milling was better than that of the traditional co precipitation method. The conversion rate of toluene could reach 50% at 2220C and the conversion of toluene at 230 C was more than 95%. at 2220C. The results show that the catalysts prepared by high energy ball milling are small in grain and rich in surface defects, which are beneficial to the complete oxidation of toluene. The stability test shows that the anti-aging ability of the catalyst prepared by the solid phase method is also stronger.
【学位授予单位】：复旦大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：O643.364

【参考文献】