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Journal of Sol-Gel Science and Technology

, Volume 89, Issue 1, pp 29–36 | Cite as

Synthesis of hierarchically porous MgO monoliths with continuous structure via sol–gel process accompanied by phase separation

  • Xuanming Lu
  • Kazuyoshi Kanamori
  • Kazuki NakanishiEmail author
Brief Communication: Nano and macroporous materials (aerogels, xerogels, cryogels, etc.)
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Abstract

Hierarchically porous magnesium oxide, MgO, monoliths with a well-defined continuous macroporous structure have been synthesized via the sol–gel route accompanied by phase separation. Magnesium chloride hexahydrate was used as a precursor, and propylene oxide was used as an acid scavenger to raise the pH of a reaction solution homogenously. In order to obtain a crack-free monolith after heating in air, poly(vinylpyrrolidone), PVP, was employed as a scaffold of the skeleton as well as a phase separation controller to form the continuous macropores with higher homogeneity. Due to the moderate hydrogen-bonding interaction with magnesium hydroxide, PVP reinforces the gel network essentially composed of fine grained magnesium hydroxide. Even after the removal of all organic components by calcination, the porous gel samples maintained their monolithic form. On the other hand, an additional incorporation of 1,3,5-benzenetricarboxylic acid, H3BTC, was found to be effective in suppressing the oriented growth of the micrometer-sized crystalline phase. The polycrystalline MgO monoliths with specific surface area of 185, 64, and 48 m2 g−1 were prepared after heating at 400, 500, and 600 °C in air, respectively.

Appearances (upper) and SEM images(lower) of monolithic MgO-based gel before and after heat-treatment.

Keywords

Magnesium oxide Sol–gel Phase separation Hierarchical pore structure Monoliths 

Notes

Acknowledgements

The present study has been performed under financial supports from Advanced Low Carbon Technology Research and Development Program (ALCA, Japan Science and Technology Agency).

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

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Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2018

Authors and Affiliations

  • Xuanming Lu
    • 1
  • Kazuyoshi Kanamori
    • 1
  • Kazuki Nakanishi
    • 1
    Email author
  1. 1.Department of Chemistry, Graduate School of ScienceKyoto University, Kitashirakawa, Sakyo-kuKyotoJapan

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