Co3O4对CO低温催化氧化的研究
关键词：Co3O4；低温催化氧化；氧空穴3818
The investigation of Co3O4 to CO low temperature
catalytic oxidation
Abstract: It is well known that CO is harmful to human healthy. During last decades, Co3O4 has attracted a mount of attentions in the scope of CO low- temperature catalytic oxidation. It showed the surprising catalytic activity for CO oxidation with 100% CO conversion at even -77 oC. It has also proved that the catalytic performance of Co3O4 depends on adsorption and activation not only to CO, but also to O2. In the present work, the catalysts of Co3O4 were prepared using the method of coprecipitation, which were pretreated in N2 atmosphere at different temperatures. At the same time, their activities for CO low temperature oxidation were tested and the surface species of catalysts and their adsorption performance were characterized with TG, IR, O2-TPD and CO-TPD. The results show that pretreating catalysts in N2 not only cleans the adsorbed water and carbonate species on the surface of the catalysts, but also promotes removal of surface oxygen species to form Co(II) and oxygen vacancies. The optimum performance of Co3O4 pretreated at 400℃ might be accounted for by the high content of oxygen species desorbed at low temperature as well as the low content of carbonate species decomposed at high temperature.
Key word: Co3O4 ；Low temperature catalytic；Oxygen vacancy
目 录
1．引言 1
1.1 前言 1
1.2 一氧化碳低温催化综述 1
1.3 Co3O4的催化特性 2
1.3.1 四氧化三钴的结构 2
1.3.2 四氧化三钴对一氧化碳的吸附 3
1.3.3 四氧化三钴对氧气的吸附 3
1.3.4四氧化三钴和助剂的催化研究 5
1.4其他催化剂的一氧化碳低温催化 8
1.4.1 金催化剂的特性 8
1.4.2 CuO-CeO2催化特性 8
1.5结论 9
1.6本课题研究目的和意义 9
1.7实验原理及方法 10
2.实验部分 11
2.1实验原料及仪器 11
2.2催化剂制备 11
2.3催化剂表征 12
2.3.1 催化剂活性测试 12
2.3.2氧气/一氧化碳程序升温脱附 12
2.3.3 FT-IR 12
3. 结果与讨论 13
4. 结论 19
5. 心得体会 20
致 谢 21
参考文献 22,3818
1.引言
1.1 前言
一氧化碳纯品为无色、无臭、无刺激性的气体。分子量28.01，密度1.250g/l，冰点为-207℃，沸点-190℃。在水中的溶解度甚低。空气混合爆炸极限为12.5%～74%。一氧化碳进入人体之后会和血液中的血红蛋白结合，进而使血红蛋白不能与氧气结合，从而引起机体组织出现缺氧，导致人体窒息死亡，所以一氧化碳是具有毒性的气体。并且由于一氧化碳是无色、无臭、无的气体，故易于忽略而致中毒。所以，对于一氧化碳的催化氧化研究成为近年来研究的热门课题之一。本文的课题是四氧化三钴作为催化剂对一氧化碳低温催化氧化的研究。四氧化三钴是具有标准尖晶石结构的过渡金属氧化物，是优良的磁性材料和催化剂材料。由于四氧化三钴在低温下具有良好的活性，并且具有相对高的表面积，气体分子很容易和充足的与催化剂相互作用。因此，四氧化三钴是一氧化碳低温催化氧化的最佳催化剂之一。