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本文介绍了合成尿素用CO2原料气除氢催化剂的理论设计依据。结合除氢催化剂的设计思想和负载型金催化剂的特性,对负载型金催化剂进行了除氢试验,结果表明负载型金催化剂具有广阔的应用前景,在催在性及耐硫性能上优于已工业应用的催化剂。 相似文献
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简要介绍了天然气高温催化燃烧的特征与机理,分别从催化剂的高温烧结、活性组分的迁移和流失、中毒、催化剂活性组分与载体的强相互作用、高温热震等引起的催化剂失活,概述了各种典型催化剂的高温失活机理,并对制备高温稳定的活泼催化剂提出了建议。 相似文献
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Catalytic performances of a series Ce/Zr oxides(CexZr1-xO2 )for soot combustion were investigated. The catalytic activities for soot combustion were affected by both the Ce/Zr ratio and the oxygen storageinvestigated. Thecapability of Ce/Zr oxides. O2-TPD and TG-DTA results indicate that CexZr1-xO2 can release its lattice oxygen continuously and promote soot combustion even no oxygen occurs in the reaction atmosphere. Among these Ce/Zr oxides, Ce0.5Zr0.5O2 has the best catalytic activity, and the ignition temperature of soot combustion was about 410℃, which is close to the practical exhaust temperature of the diesel engine. 相似文献
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用于轻型柴油车尾气排放的氧化催化剂研究进展 总被引:1,自引:0,他引:1
为满足愈加严格的柴油车尾气排放标准,不但需要对柴油车的发动机技术进行改进,同时需要采用尾气后处理技术。在柴油车尾气后处理技术中,氧化催化剂是当前实际应用最广泛的技术措施。本文介绍了轻型柴油车的欧洲排放标准及尾气排放特点,综述了轻型柴油车氧化催化剂技术的研究和开发进展。 相似文献
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CeO2-Co3O4 Catalysts for CO Oxidation 总被引:1,自引:0,他引:1
CeO2-Co3O4 catalysts for low-temperature CO oxidation were prepared by a co-precipitation method. In combination with the characterization methods of N2 adsorption/desorption, XRD, temperature-programmed reduction (TPR), and FT-IR, the influence of the cerium content on the catalytic performance of CeO2-Co3O4 was investigated. The results indicate that the prepared CeO2-Co3O4 catalysts exhibit a better activity than that of pure CeO2 or pure Co3O4. The catalyst with the Ce/Co atomic ratio 1 : 16 exhibits the best activity, which converts 77% of CO at room temperature and completely oxidizes CO at 45 ℃. 相似文献
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用碳酸铵水溶液共沉淀法制备Ba1-xLaxFeAl11O19-δ六铝酸盐型催化剂,以甲烷燃烧为探针反应考察催化剂的氧化活性.甲烷催化燃烧的结果表明,La部分取代Ba可以提高催化剂的甲烷燃烧活性,随La取代量的增加,催化剂的起燃温度发生规律性变化,镧、钡之间存在最佳配比,其中活性最好的催化剂为Ba0.2La0.8FeAl11O19-δ,其催化甲烷燃烧的起燃温度仅有495℃(V(CH4)/V(O2)/V(N2)=1/4/95).XRD和SEM结果表明,不同含量镧搀杂的材料经1200℃/5h焙烧呈现典型的六铝酸盐结构特征,不同温度的焙烧实验表明,搀杂镧能够促进六铝酸盐相的形成.Diffuse UV-Vis表征催化剂结构中铁呈+3价,DiffuseUV-Vis和FTIR表征结果表明,Ba、La、Fe之间存在协同作用. 相似文献
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Effect of calcination temperature and reaction conditions on methane partial oxidation using lanthanum-based perovskite as oxygen donor 总被引:1,自引:0,他引:1
We investigated the effect of calcination temperature, reaction temperature, and different amounts of replenished lattice oxygen on the partial oxidation of methane (POM) to synthesis gas using perovskite-type LaFeO3 oxide as oxygen donor instead of gaseous oxygen, which was prepared by the sol-gel method, and the oxides were characterized by XRD, TG/DTA, and BET. The results indicated that the particle size increased with the calcination temperature increasing, while BET and CH4 conversion declined with the calcination temperature increasing using LaFeO3 oxide as oxygen donor in the absence of gaseous oxygen. CO selectivity remained at a high level such as above 92%, and increased slightly as the calcination temperature increased. Exposure of LaFeO3 oxides to methane atmosphere enhanced the oxygen migration of in the bulk with time online owing to the loss of lattice oxygen and reduction of the oxidative stated Fe ion simultaneously, The high reaction temperature was favorable to the migration of oxygen species from the bulk toward the surface for the synthesis gas production with high CO selectivity. The product distribution and evolution for POM by sequential redox reaction was determined by amounts of replenished lattice oxygen with gaseous oxygen. The optimal process should decline the total oxidation of methane, and increase the selectivity of partial oxidation of methane. 相似文献
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以多壁碳纳米管和椰壳活性炭为载体,分别采用溶胶固载法和等体积浸渍法制备负载型纳米金催化剂。采用N_2吸附-脱附、XRD、TEM和XPS等对碳载体和纳米金催化剂样品进行表征,并研究纳米金催化剂在肉桂醛选择性加氢反应中的催化性能。结果表明,HNO_3-H_2SO_4预处理可以增加碳载体表面的含氧基团和含氮基团,在肉桂醛加氢反应中,溶胶固载法得到的更小尺寸的纳米金催化剂对C=C双键加氢选择性高,等体积浸渍法制备的纳米金催化剂对C=O双键加氢选择性高,椰壳活性炭为载体催化剂的C=C加氢催化活性优于多壁碳纳米管。 相似文献