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以类水滑石为前驱体,采用共沉淀法制备了不同Ru含量的xRu/Mg(Al)O催化剂(x=1,2,4),采用XRD、H2-TPR和CO脉冲吸附等表征催化剂结构和Ru金属分散度,并评价Ru含量对CH4-CO2重整反应活性与稳定性的影响。XRD与CO脉冲吸附结果表明,Ru含量增加时,还原后Ru金属颗粒的表面活性位数目增加,但分散度降低,Ru金属的粒径增大。活性测试结果表明,Ru质量分数为2%时,催化剂活性最高。Ru质量分数为1%时,催化剂具有较好的稳定性,归属于高分散Ru金属颗粒与Mg(Al)O载体之间的强相互作用。 相似文献
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Multiple-metal catalysts (Ni-Mn-Ce-K/bauxite) for Water-Gas Shift (WGS) reaction were prepared by impregnation, and the catalytic structure and properties were investigated by N2 physical, XRD, H2-TPR, and CO-TPD. The results indicated that the addition of 7.5% CeO2 improved the activity of the WGS reaction obviously, and also increased the specific surface area and pore volume of the catalysts. The addition of CeO2 decreases the reduction temperature, enhanced the adsorption and activation of H2O2, and improved the adsorption content of CO. Besides, active sites were not changed and the number of active sites on catalysts did not increase obviously. 相似文献
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采用内循环无梯度反应器,对工业原粒度矿制CO耐硫变换催化剂进行了宏观动力学研究。实验采用ψ4-5mm不定型颗粒催化剂,反应温度240℃-300℃,常压,体积空速为400h^-1-600h^-1。建立了简化的双曲函数型宏观动力学模型,采用麦夸特法,由实验数据获得了模型中的参数值。统计检验表明该动力学模型是适定的。 相似文献
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High thermally stable mesoporous alumina doped with lanthanum was synthesized using inorganic nitrates as precursors and employing pluronic P123 (P123, (EO20PO70EO20, EO=ethylene oxide, PO=propylene oxide)) as a structure-directing agent. After calcination at 400 oC, the resultant lanthanum doped alumina exhibited aγ-Al2O3 phase, which was the same as pure alumina. After the thermal treatment up to 1200 oC, La-doped Al2O3 generated only one phase ofθ-Al2O3 rather than two mixed phase ofθ-Al2O3 andα-Al2O3 and the surface area could still maintain 101 m2/g with a keeping pore volume of 0.66 cm3/g. The excellent thermal sta-bility was explained by the titration of strong Lewis acid sites ofγ-Al2O3 with the assistance of highly dispersed lanthanum species covering on alumina. Furthermore, the lanthanum modified mesoporous alumina was preliminarily employed as a stable support for Pd in the catalytic oxidation of C3H8. 相似文献
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采用等温管式积分反应器,在(550~750) K、(2.0~3.5) MPa和空速(15~30) L·(g·h)-1条件下,对新型钴钼系耐硫变换催化剂进行变换反应本征动力学研究。建立了包含压力项的幂函数型动力学模型,根据实验测定数据,结合具有全局寻优能力微粒群算法和求解微分方程的龙格-库塔法,通过迭代寻优对变换反应动力学模型进行参数估计,获得高度显著、可信的动力学模型。结果表明,在催化剂上进行变换反应时,反应速率对CO组分分压变化的敏感性较低,H2O组分分压对反应速率的影响较大,高汽气比下催化活性较高。 相似文献
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氨是一种无碳富氢的能源载体,体积能量密度高,易液化储存,是理想的储氢介质。以氨直接作为燃料,在低温碱性膜燃料电池中通过氨氧化反应实现化学能到电能的转化,是氨能源高效利用的理想路径之一。然而,低温氨氧化反应动力学缓慢、催化剂价格昂贵、易中毒等问题严重影响氨燃料电池性能,限制其大规模的商业化应用。因此,设计高效、廉价、稳定的催化剂是发展低温氨燃料电池技术的关键。本文首先综述了近些年研究者在氨氧化反应机理方面的探索,在深入理解反应体系的基础上,重点介绍了含贵金属和非贵金属催化剂设计制备及其在氨氧化反应中的进展,并总结了氨氧化催化剂在氨燃料电池中的性能。最后针对氨氧化催化剂目前存在的问题和未来的发展方向提出了建议,旨在为氨氧化催化剂的设计及低温氨燃料电池技术的发展提供研究思路。 相似文献
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