Solvent-Free Synthesis of MIL-101(Cr) for CO2 Gas Adsorption: The Effect of Metal Precursor and Molar Ratio

MIL-101(Cr), a subclass of metal-organic frameworks (MOFs), is a promising adsorbent for carbon dioxide (CO2) removal due to its large pore volume and high surface area. Solvent-free synthesis of MIL-101(Cr) was employed in this work to offer a green alternative to the current approach of synthesizing MIL-101(Cr) using a hazardous solvent. Characterization techniques including XRD, SEM, and FTIR were employed to confirm the formation of pure MIL-101(Cr) synthesized using a solvent-free method. The thermogravimetric analysis revealed that MIL-101(Cr) shows high thermal stability up to 350 degrees C. Among the materials synthesized, MIL-101(Cr) at the molar ratio of chromium precursor to terephthalic organic acid of 1:1 possesses the highest surface area and greatest pore volume. Its BET surface area and total pore volume are 1110 m(2)/g and 0.5 cm(3)/g, respectively. Correspondingly, its CO2 adsorption capacity at room temperature is the highest (18.8 mmol/g), suggesting it is a superior adsorbent for CO2 removal. The textural properties significantly affect the CO2 adsorption capacity, in which large pore volume and high surface area are favorable for the adsorption mechanism.

Automated summary

This study investigates the solvent-free synthesis of MIL-101(Cr) as a green alternative to the hazardous solvent method. MIL-101(Cr) demonstrates high thermal stability and its CO2 adsorption capacity is influenced by its surface area and pore volume.