Three Dimensionally Ordered Macroporous Layered Double Hydroxides: Preparation by Templated Impregnation/Coprecipitation and Pattern Stability upon Calcination

Three dimensionally ordered macroporous layered double hydroxides (3-DOM LDH) have been synthesized using sacrificial polystyrene (PS) colloidal crystal templates impregnated by divalent and trivalent metal salts. LDH spatially confined coprecipitation occurs during soaking in NaOH solution, and the PS template is subsequently removed by dissolution to preserve the hydroxyl structure. This synthetic process can be applied to a wide range of LDH compositions (MII: Mg, Ni, Co, Zn and MIII: Al, Cr). On the basis of XRD, SEM, TEM, chemical analysis, nitrogen adsorption, XAS experiments, and TGA, structural, textural, and thermal properties of these new nanostructured LDH particles are described. In particular, the study shows that both macro- and mesoporosity can be present and that the macroporosity is maintained after calcination at temperatures as high as 800 °C, giving rise to the presence of macroporous metal and mixed metal oxides. The photocatalytic activity experiments indicate that decatungstate intercalated into the 3-DOM LDH exhibits a higher photocatalytic activity for the photodegradation of 2,6-dimethylphenol than the decatungstate intercalated into the standard coprecipitated LDH parent material.