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61.
以城市污水处理厂剩余污泥为原料制备了一种新型碳质催化剂。通过试验考察了催化剂在NH3选择催化还原NO中的应用效果。结果表明,催化性能较好,最佳的制备和催化反应条件为:锌铁物质的量比1∶0.5,热解温度750 ℃,反应温度400 ℃,O2浓度15%。在此条件下,NOx的最大转化率达98.3%。通过考察证明催化剂自身具有一定的还原性能。对催化剂进行了FTIR、TG、SEM和BET分析,结果表明,催化剂具有很丰富的孔结构、活性粒子和表面官能团,比表面积较大,最大可达307 m2·g-1,分析结果显示具有良好的催化条件。 相似文献
62.
Masashi Shou Hiroyuki Takekawa Dong-Ying Ju Tokio Hagiwara Da-ling Lu Ken-ichi Tanaka 《Catalysis Letters》2006,108(3-4):119-124
Catalytic activity of a 1 wt% Au/TiO2 catalyst is markedly improved by loading a large amount of FeOx, on which the oxidation of CO in excess H2 is selectively promoted at temperature lower than 60 °C. Oxidation of CO with O2 on the FeOx/Au/TiO2 catalyst is markedly enhanced by H2, and H2O moisture also enhances the oxidation of CO but its effect is not so large as the promotion by H2. We deduced that activation of Au/TiO2 catalyst by loading FeOx is not caused by the size effect of Au particles but a new reaction path via hydroxyl carbonyl intermediate is responsible
for the superior activity of the FeOx/Au/TiO2 catalyst. 相似文献
63.
A random walk Monte Carlo (RWMC) simulation model of catalytic particle was established on the basis of the structures of bismuth molybdate catalysts and mechanisms of catalytic reactions with propylene selective oxidation and ammoxidation. The simulation results show that rationality of the RWMC model is proved on the basis of pulse experimental data. One of the most remarkable factors affecting catalytic behavior is the transfer of bulk lattice oxygen, which decides the rate of ammonia-consuming and propylene-consuming. The selectivity of main products reaches the maximum after the reduction of catalysts to a certain degree. It is inferred that catalytic performance improves greatly if the ratio of capacity for dehydrogenation from adsorbed propylene molecule on catalytically active site of molybdenum metal-imido group (Mo=NH) to that on catalytically active site of molybdenum metal-oxo group (Mo=O) becomes much higher. 相似文献
64.
NH3-NO/NO2 SCR for diesel exhausts after treatment: mechanism and modelling of a catalytic converter
Nova Isabella Ciardelli Cristian Tronconi Enrico Chatterjee Daniel Weibel Michel 《Topics in Catalysis》2007,42(1-4):43-46
We review herein the key mechanistic and kinetic features of the reactions involved in the NH3-NO/NO2 SCR system investigated by dynamic reactive experiments over a V-based commercial powdered catalyst, eventually leading to
the proposal of an original redox scheme which accounts for stoichiometry, selectivity and intrinsic kinetics of the global
SCR process. 相似文献
65.
通过实验的方法收集了不同温度下纯尿素和尿素/TiO2混合物热解后的固体残留物,使用红外光谱(IR)及气相色谱质谱联机(GC-MS)方法对这些热解残留物进行成分分析;使用热重-红外联机(TG-FTIR)技术研究尿素及三聚氰酸在有无催化剂TiO2的情况下的热解特性及气体产物的生成规律;根据Coats-Renfern方法对尿素热解第一阶段的非等温热失重率曲线的数据进行动力学研究,建立动力学方程。结果表明,100~250℃的尿素热解残留物中主要为尿素和缩二脲,300~400℃的尿素热解残留物中主要为三聚氰酸等含氮杂环有机化合物;锐钛型TiO2能促进尿素和三聚氰酸的热解反应,缩短其反应进程,HNCO与水蒸气在TiO2表面易发生反应;尿素第一阶段热解的反应级数为2,单独热解时活化能为113.25kJ/mol,指前因子A为2.01×1011min-1,在催化剂TiO2的作用下,活化能E为77.42kJ/mol,指前因子A为4.82×107min-1。 相似文献
66.
轻质油品氧化脱硫技术进展 总被引:9,自引:1,他引:9
介绍了国内外轻质油品氧化脱硫技术的研究进展情况,分析了选择性氧化脱硫、超声波氧化脱硫、光催化氧化脱硫、等离子体液相氧化脱硫等技术的优缺点,展望了氧化脱硫技术应用前景。 相似文献
67.
68.
Ragnar Larsson 《Catalysis Letters》1991,10(3-4):317-324
Kinetic data on the exchange reaction betwee hexane and deuterium have recently been reported by Maier and coworkers [1]. The reaction was catalysed by a series of platinum or rhodium systems, some of which had the property that the upper surface was shielded by a silica overlayer. The data are reinterpreted to indicate an isokinetic temperature of 580 K. This observation indicates that all the catalysts behave in a similar manner, which means that the exchange reaction does not require a free metal surface. 相似文献
69.
70.
Michael Bowker 《Topics in Catalysis》1996,3(3-4):461-468
STM has been combined with molecular beam rate measurements to gain an understanding of the oxidative dehydrogenation of methanol to produce formaldehyde, both at the macroscopic and microscopic level. From this a model of the reaction is developed where the methanol initial reacts at very few active oxygen sites located at the short sides of oxygen islands on the Cu(110) surface. Such sites are very much rarer on a surface which is saturated with 0.5 monolayers of oxygen and the reaction rate is initially very low, but shows autocatalytic behaviour, rising in time as vacancies are created in the oxygen layer. 相似文献