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研究了制备参数对用于甘油蒸汽重整反应的Ni基催化剂性能的影响.采用过量浸渍法、等体积浸渍法和改进的平衡沉积过滤(EDF)法制备了一系列Al2O3负载的8 wt%Ni催化剂,运用X射线衍射(XRD)、电感耦合等离子体光谱仪、N_2吸附-脱附、扫描电镜(SEM)、透射电镜和H2程序升温还原(TPR)表征了催化剂的表面和体相性质;采用CHN分析仪和SEM表征了使用后催化剂以测定其表面沉积的碳及其形貌.结果表明,制备方法对所制催化剂的织构、结构和表面性质影响很大,导致氧化铝表面Ni物种的分散和种类的不同.即使XRD和TPR结果证实形成了铝酸镍晶相,但Ni/Al-edf催化剂中β峰的贡献大于其它两个催化剂的,表明在这种情况下铝酸镍更容易还原.在550 ℃以上CO_2选择性增加和CO选择性不变,表明Ni/Al-wet和Ni/Al-edf催化剂可成功催化水汽变换反应.另外,650 ℃时Ni/Al-edf催化剂上甘油生成气相产物的转化率、氢气产率以及烯丙醇、乙醛和乙酸选择性最高,且它在所有催化剂中的积炭量也最低.将催化剂结构性质、分散度和还原性与其催化性能相关联,发现EDF法制得的催化剂比表面积和活性相分散度更高,更易被还原,因而其活性和生成H_2的选择性更高,也更抗积碳.
The effects of preparation parameters on the performance of Ni-based catalysts for steam reforming of glycerol were studied.The results showed that a series of 8 wt% NiO supported on Al2O3 were prepared by over impregnation method, equal volume impregnation method and modified equilibrium deposition filtration (EDF) The surface and bulk properties of the catalysts were characterized by X-ray diffraction (XRD), inductively coupled plasma (ICP), N 2 adsorption-desorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and temperature programmed reduction (TPR) Analyzer and SEM characterization of the catalyst after use to determine the surface deposition of carbon and its morphology.The results show that the preparation method of the catalyst has a great influence on the texture, structure and surface properties, resulting in dispersion of the surface of the alumina species of Ni And species differences.While the XRD and TPR results confirm the formation of a nickel aluminate crystalline phase, the contribution of the β peak in the Ni / Al-edf catalyst is greater than that of the other two catalysts, indicating that the nickel aluminate is easier to reduce in this case . The increase of CO 2 selectivity and the selectivity of CO over 550 ℃ show that Ni / Al-wet and Ni / Al-edf catalysts can successfully catalyze the water vapor shift reaction. In addition, Gas phase product Conversion, hydrogen yield, and the highest selectivity for allyl alcohol, acetaldehyde, and acetic acid, and its lowest amount of carbon in all the catalysts.Changing the catalyst structure, dispersibility, and reducibility to its catalytic performance, it was found that EDF The catalyst prepared by the specific surface area and active phase dispersion degree is higher, more easily reduced, so its activity and the selectivity of generating H_2 higher, but also more resistant to carbon deposition.