One-step green approach for synthesizing highly ordered pillaring materials via ultrafast transportation

• A one-pot approach was developed for synthesizing PCH in supercritical CO2 (scCO2).
• Low-solubility surfactant in scCO2 can be transfer into the clay interlayer.
• High diffusivity of scCO2 ensures facile transportation of CTAB into clay interlayer.
• Provide a general technique to synthesize multifunctional intercalation compounds

The intercalation of guest molecules into layered materials is an important strategy to develop multifunctional hybrid nanocomposites and porous materials. The unique mesoporous structure and the intrinsic acidity of metal oxide intercalated porous clay heterostructure (PCH) make it a promising catalytic material. In contrast to the current synthesis methods of PCH that have complex procedures and structure-controlling difficulties, a novel one-step approach with supercritical CO2 (scCO2) as medium was invented using montmorillonite (Mt) as the host matrix and cetyltrimethylammonium bromide as the structure-directing agent (SDA). In this simple and efficient approach, the high diffusivity of scCO2 ensures the facile transportation of cationic SDA into the interlayer space of Mt via ion exchange, which eliminates a requirement for the high solubility of a SDA in scCO2. As a result, the co-assembly of the SDA and the oxide precursor controlled in the interlayer space of Mt leads to the highly ordered PCH. Furthermore, this unique approach provides a general technique to synthesize multi-functional intercalation compounds.

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