The structure-directed effect of Al-based metal–organic frameworks on fabrication of alumina by thermal treatment

• We use Al-MOFs as precursor in the fabrication process of mesoporous alumina by thermal treatment.
• The obtained mesoporous alumina has dual pore system and five-fold aluminum.
• The aluminum building units in the precursor show structure-directed effect on the formation of alumina.

In this work, the block-shaped Al-based metal–organic frameworks (Al-MOFs) MIL-53 have been synthesized by hydrothermal method. To detect the correlation between the structure of Al-MOFs and the formation of alumina, the ligands are eliminated by thermal treatment. MIL-53 and the calcination products were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), transmission electron microscopy (TEM), nitrogen adsorption–desorption and solid-state 27Al nuclear magnetic resonance (27Al NMR). It was found that after calcination, the block-shaped Al-MOFs precursor turns into high-crystallinity mesoporous alumina nanosheets, and the thermal treatment product γ-alumina possesses a dual pore system and a large surface area (146 m2/g), with five-fold aluminum. During the thermal treatment process, the structure of MIL-53 and its secondary building units have structure-directed effect in the formation of alumina.

Figure optionsDownload as PowerPoint slide