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烧结型制氢催化剂中Mg和Ni组份以什么形式的物相存在,对催化剂的性能有影响。由于MgO和NiO易形成MgNiO_2固溶体,且它们的X射线衍射数据很相近,一般分析难以确定。本文通过X射线衍射法分别对用共沉法和干混法制得的MgO-NiO体系样品与催化剂样品进行对比试验,测定了这些样品中MgO和NiO对应的高角衍射区(420)衍射峰及衍射角位置的变化。并与粉末衍射卡片的MgNiO_2标准数据进行对比分析。由实验结果可得,共沉法制的MgO-NiO体系和催化剂的样品经不同温度处理时,其(420)衍射都只有一个峰,所对应的衍射角2θ与MgNiO_2固溶体的2θ值相一致。而干混法制的MgO-NiO体系,无论是未煅烧还是经煅烧的样品,都有两个对应于MgO和NiO的衍射峰,且向处于中间位置的固溶体峰靠拢。说明催化剂在热处理过程中,Mg、Al复盐分解成MgO和NiO的同时就开始形成固溶体,且随温度增高其晶型逐步完善。证实了在共沉法制备条件下制氢催化剂中的MgO和NiO形成了MgNiO_2固溶体。
The sintering type hydrogen production catalyst Mg and Ni components in what form the existence of the phase, the performance of the catalyst. Because MgO and NiO tend to form MgNiO 2 solid solution, and their X-ray diffraction data are similar, the general analysis is difficult to determine. In this paper, by contrasting the MgO-NiO system sample and the catalyst sample prepared by coprecipitation method and dry-mixing method by X-ray diffraction method, the diffraction peak of high angle diffraction (420) and diffraction Change in angular position. And compared with the standard data of MgNiO_2 powder diffraction card. From the experimental results, it can be seen that there is only one peak of the (420) diffraction in the samples of the co-precipitation MgO-NiO system and the catalyst after being treated at different temperatures, and the corresponding diffraction angle 2θ is consistent with the 2θ value of the MgNiO 2 solid solution. However, the MgO-NiO system prepared by dry blending has two diffraction peaks corresponding to MgO and NiO, both uncalcined and calcined, and moves closer to the solid solution peak in the middle. This shows that during the heat treatment, the Mg and Al complex salts decompose into MgO and NiO, and the solid solution begins to form. With the increase of temperature, the crystal form gradually improves. It is confirmed that MgO and NiO in the hydrogen production catalyst under the conditions of coprecipitation have formed MgNiO 2 solid solution.