不同形貌ZnO与Cu的相互作用及对醋酸异丙酯加氢性能的影响

发布时间：2018-05-09 20:07

本文选题：ZnO形貌 + 极性面　；参考：《高校化学工程学报》2017年01期

【摘要】：采用水热法并通过控制前驱体溶液的浓度合成了不同形貌的盘状和柱状ZnO晶体,并通过X射线衍射(XRD)、扫描电镜(SEM)、透射电子显微镜(TEM)、选区电子衍射(SAED)、拉曼光谱(Raman)及氢气程序升温还原(H2-TPR)等表征其形貌结构、生长习性及其与Cu之间的相互作用。发现随着前驱体溶液浓度的减小,ZnO晶体结构逐渐延长,六边形极性面直径减小,形状由盘状向柱状转变。然后分别将这些ZnO晶体作为助剂制备了不同形貌的Cu/ZnO催化剂,并用于醋酸异丙酯(IA)加氢合成乙醇和异丙醇的反应。结果发现:ZnO晶体的形貌结构对IA加氢催化性能有明显的影响,盘状Cu/ZnO-a催化剂具有最高的IA转化率和产物选择性;对催化活性与ZnO极性面所占比例进行了关联,得到了较好的线性关系,极性面比例越高,IA转化率越高。这归因于极性面比例较高的ZnO与Cu之间的相互作用更强,活性组分铜的分散更均匀、更容易还原,从而使催化加氢活性更高。
[Abstract]:Disk-like and columnar ZnO crystals with different morphologies were synthesized by hydrothermal method and by controlling the concentration of precursor solution. The morphology, growth habit and interaction with Cu were characterized by X-ray diffraction (XRDX), scanning electron microscopy (SEM), transmission electron microscope (TEM), selected area electron diffraction (SAEDN), Raman spectroscopy (Raman) and hydrogen temperature programmed reduction (H2-TPRR). It is found that with the decrease of the concentration of precursor solution, the crystal structure of ZnO increases gradually, the diameter of hexagonal polarity surface decreases and the shape of hexagonal polar plane changes from disk to columnar. Then these ZnO crystals were used as promoters to prepare Cu/ZnO catalysts with different morphologies and were used for the hydrogenation of isopropyl acetate to ethanol and isopropanol. The results showed that the morphology and structure of Cu/ZnO-a crystal had a significant effect on the catalytic performance of IA hydrogenation, the disk-like Cu/ZnO-a catalyst had the highest IA conversion and product selectivity, and the catalytic activity was correlated with the proportion of polar surface of ZnO. A better linear relationship was obtained, and the higher the ratio of polarity surface was, the higher the conversion rate of IA was. This is attributed to the stronger interaction between ZnO and Cu with higher polar surface ratio, the more uniform dispersion of active copper, and the easier reduction, resulting in higher catalytic hydrogenation activity.
【作者单位】：南京工业大学化学化工学院江苏省工业节水减排重点实验室;南京工业大学材料化学工程国家重点实验室;
【基金】：江苏高校优势学科建设工程资助项目(PADD)
【分类号】：O643.36

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