experiment怎么读税收分类甲苯催化燃烧钴基催化剂的制备与反应性能研究
摘要
催化燃烧技术是将挥发性有机物（VOCs）氧化为无污染的CO2和H2O 的有效途径，其首要问题是设计开发高活性、高稳定性的催化剂。负载型催化剂中，载体自身与活性组分之间产生的相互作用可增强催化剂性能。Co催化剂由于其优异的低温还原能力、高浓度的氧空穴及亲电氧物种等特点，表现出良好的催化活性。为了进一步改善Co催化剂的活性，将钴负载在载体上或者在钴催化剂上负载其他活性组分，通过钴与其他组分间的协同作用增强催化性能。
石墨相氮化碳（g-C3N4）由于其密度低、热稳定性好以及表面化学性质丰富等特点而被认为是一种优异的催化剂载体。因此，本文中，一方面设计开发g-C3N4负载氧化钴催化剂，并将其应用于甲苯催化燃烧反应中，探究g-C3N4载体对催化燃烧甲苯性能的影响。另一方面，基于催化剂的形貌效应，合成氧化钴纳米棒，并将其作为载体负载活性金属Ag，研究氧化钴纳米棒负载Ag催化剂甲苯催化氧化性能。本文的研究结果如下：（1）热聚合盐酸胍合成g-C3N4，并采用浸渍法制备CoOx/g-C3N4催化剂。作为对比，制备SBA-15、γ-Al2O3、AC负载CoOx催化剂。催化氧化甲苯发现，催化活性随着CoOx载量增加而提高，载量为10%时，实现最优的催化活性。和其他载体负载CoOx催化剂相比，10% CoOx/g-C3N4催化剂也具有最好的催化活性，279 °C实现甲苯完全转化，并且具有优异的稳定性和循环使用性。
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（2）10% CoOx/g-C3N4催化剂拥有最高的催化活性是由于表面Co3+含量高、表面吸附氧物质密度高、及Co3+低温还原能力强。
（3）与其他载体相比，氮化碳可以促进氧化钴的还原能力，并且其富N结构导致催化剂表面电子丰富，这可能是氧物种和Co物种丰富存在的原因。因此，g-C3N4可以作为良好的催化氧化VOCs催化剂载体。
（4）水热法成功制备了Co3O4纳米棒，并采用浸渍法制备Co3O4纳米棒负载Ag催化剂，探讨了Ag载量对其催化氧化性能的影响。甲苯催化氧化实验发现，Co3O4纳米棒具有良好的甲苯催化活性，随Ag负载量的增大而提高，当Ag载量达到7%时，具有最高的催化活性，其T50和T90分别为244.3 °C和256.5 °C。当Ag载量提高至10%时，甲苯的催化活性出现轻微的下降。
（5）7% Ag/Co3O4样品拥有最优的催化氧化甲苯的活性。这可能是由于Co3O4纳米棒表面Ag分散度高、表面Co3+相对含量高、表面吸附氧物质密度高，以及Co3+低温还原能力强。
关键词：石墨相氮化碳，Co3O4纳米棒，催化氧化，钴基催化剂，甲苯
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STUDIES ON PREPARATION AND REACTION PROPERTIES OF COBALT CATALYSTS FOR CATALYTIC COMBUSTION OF北京瑞思学科英语
TOLUENE
新东方外语学校ABSTRACT
Catalytic combustion technology is an effective way to oxidize volatile organic compounds (VOCs) into non-polluting CO2and H2O. The primary problem is to design and develop catalysts with high activity and stability. In a supported catalyst, the interaction generated between the support itlf and the active component enhances catalyst performance. Cobalt catalyst exhibits good catalytic activity due to its excellent low temperature reducing ability, high concentration of oxygen vacancies and electrophilic oxygen species. In order to further improve the activity of the cobalt catalyst, cobalt is supported on the support or other active components are supported on the cobalt catalyst, and the catalytic performance is enhanced by the synergy between cobalt and other components.
Graphitic carbon nitride (g-C3N4) is considered to be an excellent catalyst support due to its low density, good thermal stability and rich surface chemical properties. In this paper, the g-C3N4supported cobalt oxide catalyst was designed and developed, and it was applied to the catalyti
c combustion reaction
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of toluene. The effect of g-C3N4on the catalytic combustion of toluene was investigated. On the other hand, bad on the morphological effect of the catalyst, cobalt oxide nanorods were synthesized and ud as a carrier to support the active metal Ag. The catalytic oxidation performance of the cobalt oxide nanorod-supported Ag catalyst was studied. The results of this work are as follows:
(1) Thermal polymerization of guanidine hydrochloride to synthesize g-C3N4, and preparation of CoOx/g-C3N4 catalyst by impregnation method. For comparison, SBA-15, γ-Al2O3, AC supported CoOx catalysts were prepared. Catalytic oxidation of toluene showed that the catalytic activity incread with the increa of CoOx loading, and the optimal catalytic activity was achieved when the loading was 10%. Compared with other supported CoOx catalysts, the 10% CoOx/g-C3N4catalyst also has the best catalytic activity, achieving complete conversion of toluene at 279 °C, and excellent stability and recycling.物主代词
(2)The highest catalytic activity of 10% CoOx/g-C3N4 catalyst is due to the existence of high surface
时代周刊谈2020年Co3+content, high density surface adsorbed oxygen species, and reducibility of Co3+ at low temperature.
(3) Compared with other supports, carbon nitride can promote the reducing ability of cobalt oxide, and its N-rich structure leads to electron richness on the surface of the catalyst, which may be the reason for the abundant prence of oxygen and Co species. Therefore, g-C3N4 can be ud as a catalyst support for good catalytic oxidation of VOCs.forover
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(4)The Co3O4nanorods were successfully prepared by hydrothermal method, and the Co3O4nanorod-supported Ag catalyst was prepared by impregnation method. The effect of Ag loading on its catalytic oxidation performance was discusd. The catalytic oxidation of toluene showed that Co3O4nanorods have good toluene catalytic activity and increa with the increa of Ag loading. When the Ag loading reaches 7%, it has the highest catalytic activity, T50 and T90 are 244.3 °C, 256.5 °C. When the Ag loading was incread to 10%, the catalytic activity of toluene showed a slight decrea.
(5) The 7% Ag/Co3O4 sample has the best catalytic activity for oxidizing toluene. This may be due to
the high dispersion of Ag on the surface of Co3O4 nanorods, the high relative content of Co3+ and adsorbed oxygen species on the surface, and reducibility of Co3+ at low temperature.在先翻译
KEY WORDS: g-C3N4, Co3O4nanorod,catalytic combustion, cobalt-bad catalyst, toluene
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