酸刻蚀制备CoOxLaCoO3及甲苯催化氧化研究毕业论文
2022-01-16 19:50:31
论文总字数：22506字
摘 要
挥发性有机物逐渐成为最主要的大气污染物，对人们的日常生活产生一定的困扰。治理VOCs是当今治理环境保护的关键。催化氧化法治理VOCs不仅仅效率高，而且产物大多为无污染的简单化合物。催化氧化法的效率取决于催化剂的选择。钙钛矿催化剂对VOCs催化效果优异，且具有良好的耐高温、耐腐蚀性。
本文对LaCoO3催化剂进行酸刻蚀处理，改变La / Co比例，制备得到一系列CoOx/LaCoO3催化剂。再利用ICP、XRD等表征手段研究CoOx/LaCoO3催化剂的理化性质，并考察LCO催化剂催化氧化甲苯的活性测试。结果表明，所有改性后的LaCoO3催化剂的孔容、孔径、比表面积都有所提升，低温还原性能和氧的流动性得到了改善。其中，LCO-2（刻蚀20 min）催化剂表现出了最优异的甲苯催化氧化性能，这是由于它具有最大的比表面积、孔容、孔径和最多的表面氧物种和最多的Co2 。LCO-2催化剂有着最小的Ea值，仅有46.2 kJ/mol，表明相较于其他LCO催化剂，甲苯更易在LCO-2发生活化作用，促进催化氧化反应的进行。
关键词： VOCs 催化燃烧 酸刻蚀法 构效关系
Preparation of CoOx/LaCoO3 by Acid Etching and the Research in Catalytic Oxidation of Toluene
ABSTRACT
Volatile organic compounds have gradually become the most important atmospheric pollutants, which would be detrimental to people's daily lives. Treating VOCs is the key to managing environmental protection today. Catalytic oxidation of VOCs is not only efficient, but also produce mostly simple, non-polluting products. The efficiency of the catalytic oxidation process depends on the choice of catalyst. The perovskite catalyst has exhibited excellent catalytic performances on eliminating VOCs, and has better high temperature stability and corrosion resistance.
In this study, LaCoO3 catalyst was etched to prepare CoOx/LaCoO3 catalyst. A series of CoOx/LaCoO3 catalysts were synthesized by changing the CoOx content by changing the acid etching time. The physicochemical properties of CoOx/LaCoO3 catalysts were studied by ICP and XRD. The catalytic properties of VOCs were also investigated by employing toluene as a reactant probe molecule. The results showed that the pore volume, pore diameter and specific surface area of all modified LaCoO3 catalysts were improved, and the reduction performance and oxygen fluidity were also improved. Among these catalysts, LCO-2 (etched 20 min) catalyst showed the most excellent catalytic oxidation performance of toluene, due to its largest specific surface area, pore volume, pore diameter, the most surface oxygen species and the most Co2 . Moreover, the LCO-2 catalyst has the lowest Ea value (46.2 kJ /mol), indicating that toluene is more easily activated over the LCO-2 catalyst compared to other LCO catalysts.
Keywords: VOCs catalytic combustion acid etching
目录
摘 要 I
ABSTRACT II
目录 I
第一章 绪论 1
1.1课题背景 1
2.1 VOCs简介及其常规处理技术 2
1.2.1 VOCs简介 2
1.2.2 VOCs的处理技术 2
1.3 催化剂进展研究 4
1.3.1 贵金属催化剂 4
1.3.2 过渡金属催化剂 4
1.4 钙钛矿型催化剂 5
1.5 本文实验思路 5
第二章 实验部分 6
2.1 实验原料及仪器 6
2.2 催化剂的制备 7
2.3 催化剂的表征 7
2.3.1 ICP 7
2.3.1 XRD 7
2.3.2 N2吸附-脱附 7
2.3.3 H2-TPR 8
2.3.4 O2-TPD 8
2.3.5 SEM 8
2.3.6 XPS 8
2.4 催化剂性能评价 8
第三章 催化氧化甲苯性能研究 10
3.1催化剂制备 10
3.2 表征结果分析 10
3.2.1 ICP 10
3.2.2 XRD 11
3.2.3 N2吸附-脱附测试 12
3.2.4 SEM 13
3.2.5 H2-TPR 14
3.2.6 O2-TPD 14
3.2.7 XPS 16
3.3 催化剂性能评价 18
3.3.1 活性评价 18
总 结 21
参考文献 22
致 谢 25
第一章 绪论
1.1课题背景
随着工业发展，现在的生活环境中存在着对人们的身体健康有着危害的污染物，严重影响着人们的日常生活。其中危害较大的一种就是挥发性有机物(VOCs)。
VOCs是一类有机物的统称，它们的特点是常温下饱和蒸气压大于133.32 Pa、标准大气压(101 kPa)下沸点处于50 °C~260 °C或者常温常压下挥发性较大[1-3]。常见的VOCs见下表1-1[4-6]。
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