Impact of surfactants and acids on the sol–gel synthesis of MgO aerogels

• A sol–gel synthesis of porous magnesium oxide aerogels from liquid precursors and supercritical drying of the wet gels is reported.
• We report the possibility to add structure directing agents to the magnesium methoxide precursor solution.
• The addition of structure directing agents has great influence on the morphology of the synthesized amorphous MgO aerogels.
• The interaction between structure directing agents and magnesium(II) ions and/or growing magnesia particles can be influenced by the addition of several acids.

AbtractMagnesium oxide (MgO) has been found to be an efficient solid base catalyst in heterogeneous catalytic reactions and an excellent adsorbent for the chemisorption of carbon dioxide. Both applications require materials with high specific surface areas and with accessible particle surface morphologies. Traditional synthesis methods can often not fulfill those requirements and new synthetic approaches are necessary. Sol–gel processing is known as an appropriate route for the controlled formation of homogeneous solid particles with high specific surface areas from liquid precursor solutions. In this work we report the influence of structure directing agents on the sol–gel synthesis of amorphous MgO aerogels. Specifically, we discuss the difference between non-ionic and ionic surfactants as well as the influence of several acids on the properties of the sol–gel products.

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