催化分解被认为是目前工业氧化亚氮减排的最有前景的技术方法，而基于Co分子筛的催化材料是目前应用于该技术最有吸引力的一种催化剂体系。论文在系统考察了分子筛载体和Co负载量对Co分子筛催化分解氧化亚氮活性影响的基础上，揭示了反应的活性位，并合成了高活性、高稳定性的Co-MOR催化剂，研究了硝酸尾气中各种干扰气体对催化活性的影响和实际工业应用的潜质。特别是针对催化反应过程和机制进行了深入的探讨。主要内容如下： 1、分子筛结构和Co负载量对Co分子筛催化N2O分解性能的影响研究 采用离子交换法制备了一系列不同负载量的4种钴分子筛（Co-ZSM-5，Co-USY，Co-BEA，Co-MOR），通过 XRD、氮气吸脱附、H2-TPR 和 in-situ NO FTIR等表征手段深入研究了材料的物理化学性质，系统考察了催化材料对N2O催化分解反应的性能。明确分子筛结构和Co负载量对Co分子筛催化N2O分解反应影响，揭示Co分子筛催化N2O分解反应的活性位。 研究发现Co分子筛催化剂中分子筛载体结构对Co物种的形成和它们的活性有非常重要的影响。在Co-USY催化剂中主要形成钴氧化物，而在Co-ZSM-5、Co-BEA和Co-MOR中Co物种主要以离子交换位上孤立的Co2+离子为主，是N2O分解反应的活性位，并且它们的活性随着分子筛载体而变化。α位Co2+离子是Co-ZSM-5中的反应活性位，并且是Co-ZSM-5、Co-BEA 和Co-MOR三种分子筛催化剂中活性最高的。Co-MOR中大量的β位Co2+离子和分子筛的结构能够形成近邻的的Co2+离子对，促进了N2O在相邻Co离子上合作活化，提高了其活性，因此Co-MOR催化剂在Co-ZSM-5、Co-BEA 和Co-MOR催化剂中表现了最高的N2O转化率。 2、缓冲条件下制备的Co-MORBIE分子筛催化N2O分解性能研究 在pH为8的缓冲体系中成功制备了具有高的钴含量和高N2O分解活性的CoMOR-BIE催化剂。CoMOR-BIE催化剂活性显著高于传统的离子交换法和浸渍法制备的CoMOR催化剂。BIE法相对于传统的WIE制备的催化剂活性更高的原因是由于在缓冲条件下Co2+离子水解为Co(OH)+更有利于Co与分子筛离子交换，提高了钴含量，并且大部分钴存在于离子交换位上。并且CoMOR-BIE催化剂具有很强的抗O2，NO 和 H2O中毒能力，在模拟硝酸尾气条件下具有非常高的活性和稳定性，因此具有潜在的应用价值。NH3-TPD和H2-TPR表征结果表明CoMOR-BIE催化剂具有较高的Co2+/Al比和低的酸性，能够使大部分Co2+保持在离子交换位上，而WIE催化剂在反应中Co大部分团聚为非活性的CoOx团簇体。 3、CoFe-MOR双金属分子筛催化N2O分解性能研究 钴铁双金属交换可以使钴的高活性和铁的高稳定性优势互补。Co、Fe之间存在着强烈的相互作用，将Fe引入Co-MOR催化剂以后能够显著提高催化剂的活性和稳定性。所制备的CoFe-MOR催化剂能够在硝酸厂尾气条件下在420℃催化分解90%以上的N2O，并且活性保持100小时以上，具有较大应用价值。铁引入后，更多钴离子存在于β位上，促进了N-NO断裂的N2O活化过程，从而实现NO促进的N2O分解过程，提高反应活性。EXAFS结果表明，铁促进了β位上的钴离子与分子筛骨架的结合，阻碍其迁移到非活性的钴氧化物或团簇体相，从而保持其高活性。 4、第二离子引入对Co-MOR催化N2O分解性能影响 在所考查的第二离子（Ce、K、La、Ni、Mo和 In）中， In离子引入后，不仅在纯N2O气氛下Co-MOR催化N2O分解活性得到了促进，并且在水存在时其催化稳定性也得到了显著提高，而La, Mo和K对Co-MOR的稳定性表现出了显著促进作用。并且，K离子引入对催化分解反应活性具有抑制作用。根据表征结果，In引入对Co-MOR催化N2O分解活性和稳定性提高归因于铟引入后，更多钴离子存在于β位上，增加了反应活性位，并且与分子筛骨架结合更强。而K引入对Co-MOR催化N2O分解活性抑制作用主要归因于形成了更多的CoOx团簇体或者Co3O4纳米粒子。La 和Mo引入后，更多的钴离子分布于γ位上，与分子筛骨架结合更强，阻碍其迁移到非活性的钴氧化物或团簇体相，从而保持其高活性，因此稳定性得到显著提高。

      Catalytic decomposition of nitrous oxide is regard as the most promising technology applied in the nitric acid plant. Among various catalysts, Co-zeolite is the most attractive and prospective material in the catalytic decomposition of nitrous oxide. In this thesis, the effects of zeolite structure and Co loading on the activities of catalytic decomposition were studied and the active active sites were revealed. Efficient N2O decomposition Co-MOR catalysts, with high activity and stability were prepared and their activities of catalytic decomposition under the simulated emission conditions of nitric acid manufacture were evaluated. Furthermore, the factors to influence the catalytic activities are discussed and the reaction mechanisms are also studied. Some understandings are summerized as followed: 1) Decomposition of nitrous oxide over Co-zeolite catalysts: role of zeolite structure and active site A series of Co exchanged zeolite catalysts with ZSM-5, BEA, MOR and USY structures were prepared and investigated for N2O catalytic decomposition under identical reaction conditions. It is found that Co-zeolites with different structures show dramatic different catalytic activities, which could be attributed to various Co species formed in them. Co-ZSM-5, Co-BEA and Co-MOR exhibit much higher activities than Co-USY catalyst, which is ascribed to the predominantly formation of active isolated Co2+ ions on the ion exchange positions; while in Co-USY Co mainly exist as less active Co oxides. Moreover, it is observed that the activities of Co2+ ions in ZSM-5, BEA and MOR zeolites are quite different and are related to the specific Co ions sites presented in each zeolite structure. In Co-ZSM-5, the most active sites are the α type Co ions, which are weakly coordinated to framework oxygens in the straight channel. On the other hand, in Co-BEA and Co-MOR, the most active sites are β type Co ions, which are coordinated to the framework oxygens of the elongated six-member ring of BEA and the interconnected small channel of MOR, respectively. The main factors affecting the activities of these individual Co ions are indicated to be their locations in the zeolite structure, their chemical coordination and the distances between the Co ions. The highest activity of the α type Co ions in ZSM-5 could be attributed to their favorite location in the zeolite and weak coordination to framework oxygens, which make them easily accessible and coordinated to reactants. The large number of β sites and their structural arrangement in MOR allow the formation of unique two adjacent β Co ions in Co…Co pairs, which provide cooperation on N2O splitting and consequently yield the high activity of β Co ions in MOR. 2) CoMOR zeolite catalyst synthesized by buffered ion exchange for effective decomposition of nitrous oxide Co contained MOR zeolite catalysts with high Co loadings were successfully synthesized by buffered ion exchange at pH 8, and were tested for N2O catalytic decomposition. The high exchange level of synthesized CoMORx-BIE catalysts probably benefits from the maximizing hydroxycomplexes Co(OH)+ ion in the buffered solution, which is more preferred for the ion exchange with the zeolites. It has been found that the novel CoMORx-BIE catalysts exhibit excellent catalytic activities, which is attributed to the large population of isolated Co2+ ions on ion exchange positions. The most active CoMOR130-BIE catalyst shows high resistance to the inhibition of oxygen, NO and water vapor. Furthermore, stability tests indicate that the CoMOR130-BIE catalyst has no obvious deactivation under simulated emission conditions after reaction for more than 100 h. This extraordinary durability could be related to its high Co2+ content and low Brönsted acidity sites in the catalyst, which facilitate the stability of active isolated Co2+ on ion exchange positions. Thus, the CoMOR130-BIE shows a great potential as a cost-effective catalyst for N2O elimination in future applications. 3) Investigation of nitrous oxide decomposition over highly active and stable bimetallic CoFe-MOR zeolite catalyst In this chapter, monometallic Co-mordenite (MOR) and bimetallic CoFe-MOR catalysts were prepared via simple wet ion exchange and tested for N2O decomposition. Strong promotion effect of Fe on the activity and stability of Co ions in the zeolites were obtained. To explore the origin of this promotion effect, X-ray diffraction, H2-temperature programmed reduction, UV-vis spectroscopy, extended X-ray absorption fine structure analysis, and N2O temperature-programmed desorption were used to characterize the bimetallic and monometallic catalysts. The characteristic results indicated that higher content of Co ions located at β sites after Fe addition, which provided cooperation on N2O splitting by two neighbored Co ions. Consequently, a greater amount of surface NOx species were formed in situ and were more strongly bonded to the catalyst, facilitating the removal of O and making the activity increased. Moreover, extended X-ray absorption fine structure analysis indicated that β-type Co ions exhibited stronger coordination to framework oxygen after Fe addition, and higher exchange level was obtained in the bimetallistic CoFe-MOR. Both of them contribute to prevent the relocation of Co2+ ions to form cobalt oxides, thus, high activity maintained. Consequently, CoFe-MOR demonstrates a superior catalytic activity and a high durability in N2O decomposition, showing great potential as a cost-effective catalyst for N2O elimination in future applications. 4) Promotion effects and mechanism of Indium cation on activity and stability of isolated Co2+ ions in MOR for nitrous oxide decomposition Among the second components tested, the incorporation of In not only improves the activity of Co-MOR, but also significantly improves the durability of Co ions in MOR, while La, Mo and K introduced only enhanced the durability. Besides, K introduction had detrimental effect on the activity of Co-MOR. Based on the characteristic results the promotion effect of In on the activity of Co-MOR is mainly attributed to the higher content of Co ions located at the active β sites after In addition, which are the active sites for N2O decomposition. The promotion effect of La and Mo on the stability of Co-MOR is mainly attributed to the higher content of Co ions located at the γ sites after La and Mo addition. The EXAFS results indicate that these β type Co ions in CoIn-MOR and γ type Co ions in CoLa-MOR and CoMo-MOR exhibit stronger coordination to framework oxygens, preventing its relocation into CoOx clusters thus the activity could be kept.