Comparative Study of Sol-Gel and Coprecipitated Ni-Al Hydrotalcites

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• 作者：Mihaela Jitianu ; Marina B?l?soiu ; Maria Zaharescu ; Andrei Jitianu and Alexandru Ivanov
• 关键词：hydrotalcite ; layered compounds ; sol ; gel ; mixed oxides ; temperature programmed reduction
• 刊名：Journal of Sol-Gel Science and Technology
• 出版年：2000
• 出版时间：2000
• 年：2000
• 卷：19
• 期：1/3
• 页码：453-457
• 全文大小：KB
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Chemistry
  Ceramics,Glass,Composites,Natural Materials
  Inorganic Chemistry
  Optical and Electronic Materials
  Nanotechnology
  
• 出版者：Springer Netherlands
• ISSN：1573-4846

文摘

Hydrotalcite is an anionic clay mineral (layered double hydroxide) whose general formula is [M(II)_1–xM(III)_x(OH)₂]x+X_x/nn–·mH₂O. Anionic clays with a hydrotalcite-type are widely used as useful precursors of multicomponent catalysts. Hydrotalcites with Ni/Al molar ratio 2.5 have been synthesised both by the coprecipitation method, starting with nickel and aluminium nitrates and by the sol-gel method, using nickel acetylacetonate and aluminium isopropylate as precursors. The NiO-Al₂O₃ oxidic forms have been obtained by the thermal treatment of the precursors at 450°C and 900°C, respectively, and were characterised by DTA, XRD, IR spectroscopy and temperature programmed reduction (TPR). TPR clearly demonstrated a higher reducibility of the oxidic forms derived from the sol-gel synthesised precursors.