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首页> 外文会议>Symposium on Recent Advances in Catalytic Materials December 2-4, 1997, Boston, Massachusetts, U.S.A. >Surface characterization of W/Ni/Al_2O_3 catalysts
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Surface characterization of W/Ni/Al_2O_3 catalysts

机译：W / Ni / Al_2O_3催化剂的表面表征

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摘要

Catalysts containing tungsten and nickel oxides are important in hydrodesulfurization (HDS), hydrogenation (HY), and steam reforming of hydrocarbons. A series of W/Ni/Al_2O_3 catalysts was prepared by two different methods: (1) coprecipitation of nickel and aluminium hydroxicarbonate from their nitrates, followed by calcination and impregnation of turngsten; (2) precipitation of boehmite from aluminium nitrate, followed by impregnations of nickel, firstly, and tungsten. The nickel content was kept constant, while the amount of tungsten varied from 2.5 to 15.5 wt-percent . The resulting oxides were characterized by inductively coupled plasma spectroscopy (ICP), atomic absorption spectroscopy (AAS), X-ray diffraction (XRD), temperature programmed reduction (TPR), and X-ray photoelectron spectroscopy (XPS). ICP and AAS were used to determine the W, Ni, and Al concentrations. XRD detected two phases: NiO and NiAl_2O_4 (no phase containing metallic tungsten was detected). Increasing the amount of W, the quantity of NiAl_2O_4 rose, the quantity of NiO decreased, and the particle size of NiO enlarged. The TPR profiles presented three peaks: one at about 1000 deg C, associated to a very stable phase; for the samples prepared by coprecipitation, the other two peaks corresponded to "free NiO" and a nonstoichiometric aluminate. For the samples prepared by impregnation, those peaks corresponded to NiO and NiAl_2O_4. XPS identified Al_2O_3, NiAl_2O_4, and Al_2(WO_4)_3 for both preparation methods, Increasing the amount of tungsten in the impregnated samples, NiWO_4 was also observed.
机译：含钨和氧化镍的催化剂在烃的加氢脱硫（HDS），加氢（HY）和蒸汽重整中很重要。通过两种不同的方法制备了一系列W / Ni / Al_2O_3催化剂：（1）将镍和氢碳酸氢铝的硝酸盐共沉淀，然后煅烧和浸渍Turngsten。 （2）从硝酸铝中沉淀勃姆石，然后首先浸渍镍和钨。镍含量保持恒定，而钨的量为2.5至15.5 wt％。通过电感耦合等离子体光谱（ICP），原子吸收光谱（AAS），X射线衍射（XRD），程序升温还原（TPR）和X射线光电子能谱（XPS）对所得氧化物进行表征。 ICP和AAS用于确定W，Ni和Al的浓度。 XRD检测到两个相：NiO和NiAl_2O_4（未检测到含金属钨的相）。 W增加，NiAl_2O_4增加，NiO减少，NiO粒径增大。 TPR曲线呈现三个峰：一个在大约1000摄氏度，与一个非常稳定的相相关；另一个在1000摄氏度左右。对于通过共沉淀制备的样品，其他两个峰分别对应于“游离NiO”和非化学计量的铝酸盐。对于通过浸渍制备的样品，那些峰对应于NiO和NiAl_2O_4。 XPS识别了两种制备方法中的Al_2O_3，NiAl_2O_4和Al_2（WO_4）_3，增加了浸渍样品中的钨含量，还观察到了NiWO_4。

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