Laboratorio de Materiales Avanzados, Departamento de Química Inorgánica - Instituto Universitario de Materiales de Alicante, Universidad de Alicante, Apartado 99, E-03080 Alicante, Spain.
J Colloid Interface Sci. 2012 Oct 1;383(1):148-54. doi: 10.1016/j.jcis.2012.06.026. Epub 2012 Jun 20.
Ni-based catalysts supported on Zn-modified alumina were investigated in the ethanol steam reforming reaction. A commercial γ-alumina was impregnated with different amounts of zinc nitrate (0, 2, 5, 10, 15, 20 wt.% on Zn basis), calcined, and then impregnated with nickel nitrate aqueous solutions. The samples were characterized by a number of techniques: N(2) adsorption at 77 K, X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray fluorescence (XRF), and temperature-programmed reduction (TPR). Their catalytic behavior in the ethanol steam reforming reaction was studied at 873 K, with a H(2)O/ethanol ratio of 5:1. Two effects of the presence of Zn were detected. On the one hand, zinc modifies the surface structure and the surface chemistry of the catalysts by formation of zinc aluminates, and on the other hand, zinc oxide can be reduced to metallic zinc under reaction conditions, thus modifying the catalytic properties of the active phase. The presence of Zn increases the ethanol conversion to gaseous compounds as compared with the catalyst supported on the Zn-free commercial alumina. The addition of a small amount of Pt (1 wt.%) causes a beneficial effect in the reaction. When Ni catalysts were used without a previous reduction treatment, ethylene was formed in high amounts; however, the Pt-Ni catalysts need no reduction pre-treatment to achieve high H(2) yields (close to 70%) and showed a high stability versus time on stream because of the control of the production of ethylene, a coke precursor.
在乙醇蒸汽重整反应中，研究了负载在 Zn 改性氧化铝上的 Ni 基催化剂。商业γ-氧化铝用不同量的硝酸锌（Zn 基 0、2、5、10、15、20wt.%）浸渍、煅烧，然后用硝酸镍水溶液浸渍。采用多种技术对样品进行了表征：77K 下的 N2 吸附、X 射线衍射（XRD）、透射电子显微镜（TEM）、X 射线荧光（XRF）和程序升温还原（TPR）。在 873K、H2O/乙醇比为 5:1 的条件下，研究了它们在乙醇蒸汽重整反应中的催化性能。检测到 Zn 存在的两个影响。一方面，锌通过形成锌铝酸盐来修饰催化剂的表面结构和表面化学性质，另一方面，氧化锌在反应条件下可还原为金属锌，从而修饰了活性相的催化性能。与负载在无 Zn 商业氧化铝上的催化剂相比，Zn 的存在提高了乙醇转化为气态化合物的转化率。添加少量 Pt（1wt.%）对反应有有益的影响。当使用未经还原预处理的 Ni 催化剂时，会形成大量的乙烯；然而，Pt-Ni 催化剂不需要还原预处理就可以获得高的 H2 产率（接近 70%），并且由于控制了乙烯（一种焦炭前体）的生成，表现出很高的稳定性。
