共查询到20条相似文献,搜索用时 125 毫秒
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在费托合成反应中,Ti通常起到助剂的作用,Ti的加入能够有效的改变催化剂的物理化学性质,进而改变催化剂费托合成反应的活性及选择性。本文研究了Ti的引入方式对钴基费托合成催化剂催化性能的影响。制备了Ti修饰载体Al2O3的钴基费托合成催化剂Co3/Ti-Al2O3和Ti修饰活性组分前驱体的钴基费托合成催化剂Co3-Ti/Al2O3,分别对其进行了FT-IR、BET、TG、XRD、TPR、TPD、TEM等表征,并研究了其费托催化性能。结果表明,以两种不同方式引入助剂钛后得到的两个催化剂Co3/Ti-Al2O3和Co3-Ti/Al2O3的选择性和活性情况基本一致。 相似文献
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氧化物助剂促进的钴基催化剂具有费托合成反应活性和长链烃选择性高等特点,是高选择性地获得馏分油的关键,具有良好的应用和研究价值。本文针对氧化物助剂对钴基催化剂的促进作用,综述了氧化物助剂对钴基催化剂的结构、稳定性以及费托合成反应性能的影响,详细分析了氧化物助剂对钴基催化剂的还原性能和分散度的影响, 同时介绍了影响氧化物助剂促进作用的因素,重点讨论了氧化物助剂的促进作用机理。并对如何更好地发挥氧化物助剂在钴基催化剂中的促进作用进行了展望:应加强氧化物助剂对钴基催化剂促进作用机理的基础研究,并且重视影响氧化物助剂促进作用的因素。 相似文献
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本研究使用机器学习方法对钴基费托合成催化剂相关文献数据进行分析,研究催化剂结构及反应条件对费托反应活性的影响。收集了近年钴基费托合成催化剂相关文献,对催化剂组成及其物理性质、制备条件、评价条件进行统计。基于机器学习方法,采用不同回归模型对数据进行分析。结果表明随机森林算法对数据的拟合程度最高,R2值达到0.984。特征重要性分析表明,催化剂中Co3O4颗粒直径对反应选择性影响最高。部分依赖图表明较小的Co3O4粒径有利于C2~C4的选择性,反之则有利于C5+产物的选择性。本研究为进一步理解钴基费托合成催化剂的结构与性能关系提供了理论依据。 相似文献
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综述了近十年来铁基催化剂在费托合成反应中的研究进展,探讨了铁基催化剂活性组分的确定及影响铁基催化剂活性组分的因素,对比了3种催化剂制备方法(熔融法、沉淀法、负载法)和5种催化剂载体(氧化物、分子筛、碳材料、双孔材料和核壳材料)对费托合成反应性能的影响,从反应活性、选择性和反应稳定性3个方面阐述了助催化剂在费托合成反应中的作用。分析认为:碳化铁是铁基费托合成催化剂的活性组分;在铁基催化剂的制备过程中,选择适宜的制备方法、载体、助催化剂,可以达到提高费托合成反应活性、目的产物选择性和反应稳定性的效果。提出合成特定结构碳化铁、进一步研究铁基催化剂反应机理仍是未来研究的重点。 相似文献
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Amalia Luz Costa Pereira Juan Maria González-Carballo Francisco José Pérez-Alonso Sergio Rojas José Luis Garcia Fierro Maria do Carmo Rangel 《Topics in Catalysis》2011,54(1-4):179-189
The effect of mesostructuration of beta zeolite and of metal loading on the properties of cobalt-based catalysts for Fischer–Tropsch synthesis was studied in this work. The most active catalyst was the mesostructured beta zeolite-supported cobalt (10%), which also showed a low selectivity to methane and the lowest olefin/paraffin ratio. 相似文献
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Jianmin Xiong Yunjie Ding Tao Wang Li Yan Weimiao Chen Hejun Zhu Yuan Lu 《Catalysis Letters》2005,102(3-4):265-269
The cobalt carbide (Co2C) species was formed in some activated carbon supported cobalt-based (Co/AC) catalysts during the activation of catalysts. It was found that the activity of Fischer–Tropsch reaction over Co-based catalysts decreased due to the formation of cobalt carbide species. Some promoters and pretreatment of activated carbon with steam could restrain the formation of cobalt carbide. 相似文献
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《Journal of Catalysis》2007,245(2):470-476
Cobalt metal nanoparticles ca. 4–5 nm in size synthesized in the core of reverse micelles and supported on surface-protected delaminated ITQ-2 zeolite display a very narrow particle size distribution and a high reducibility typical of larger particles. The methodological preparation approach presented here allows breaking of the dispersion–reducibility dependence inherent to very small cobalt particles supported on oxidic carriers, thereby overcoming long-lasting difficulties in studying particle size effects in highly dispersed cobalt-based Fischer–Tropsch catalysts. 相似文献
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Preparation and properties of supported cobalt catalysts for Fischer-Tropsch synthesis 总被引:1,自引:0,他引:1
J. van de Loosdrecht M. van der Haar A.M. van der Kraan A.J. van Dillen J.W. Geus 《Applied Catalysis A: General》1997,150(2):684-376
Alumina-supported cobalt catalysts have been prepared from different cobalt precursors to study the influence of the precursor on the ultimate metal particle size. Furthermore, the effect of the particle size on the catalytic performance (activity and selectivity) during Fischer-Tropsch synthesis has been investigated. The preparation of low-loaded cobalt catalysts (2.5 wt%) by incipient wetness impregnation using cobalt EDTA and ammonium cobalt citrate precursors resulted initially in very small cobalt oxide particles, as determined by XPS. The small oxide particles reacted during the thermal treatment in a reducing gas flow with the alumina support to cobalt aluminate, which was neither active nor selective during Fischer-Tropsch synthesis. The catalysts prepared with cobalt nitrate had larger particles that could be easily reduced to metallic cobalt. These catalysts were active under reaction conditions. High-loaded cobalt catalysts (5.0 wt%) prepared using ammonium cobalt citrate showed a larger particle size than the low-loaded catalyst prepared from the citrate precursor. The extent of reduction to metallic cobalt that could be achieved with the high-loaded catalyst was significantly higher than that with the low-loaded catalyst, as shown by magnetic measurements. Accordingly, the high-loaded catalyst exhibited a reasonable activity and, in addition, an interesting and remarkably high selectivity toward higher hydrocarbons, and also a very high Schultz-Flory parameter. 相似文献
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Suk-Hwan Kang Jae-Hong Ryu Jin-Ho Kim P. S. Sai Prasad Jong Wook Bae Joo-Young Cheon Ki-Won Jun 《Catalysis Letters》2011,141(10):1464-1471
Abstract
Fischer–Tropsch synthesis (FTS) reaction for the direct production of gasoline range hydrocarbons (C5–C9) from syngas was investigated on cobalt-based FTS catalyst supported on the ZSM-5 possessing a four different Si/Al ratio. The FTS catalysts were prepared by impregnation method using cobalt nitrate precursor in a slurry of ZSM-5, and they were characterized by surface area, XRD, H2-TPR and NH3-TPD. Cobalt supported catalyst on ZSM-5 having a low Si/Al ratio of 15 was found to be superior to the other catalysts in terms of better C5–C9 selectivity due to the formation of small cobalt particle and the presence of larger number of weak acidic sites. It also exhibited the highest catalytic activity because of the higher reducibility and the small cobalt particle size. 相似文献20.