Enhancing CO<sub>2</sub> Adsorption in MIL-53(Al) through Pressure–Temperature Modulation: Insights from Guest–Host Interactions
Jingyan Liu, Boqing Li, Vinícius Martins, Yining Huang, Yang Song
Abstract
Metal–organic frameworks (MOFs) have garnered significant attention for their exceptional CO 2 adsorption capabilities. Among them, MIL-53(Al) is uniquely known for its “breathing effect”, a reversible phase transition between large-pore and narrow-pore phases. While previous studies have explored the structural changes in MIL-53(Al) under varying conditions, this work represents an innovative investigation into the simultaneous effects of high pressure and high temperature on the CO 2 adsorption performance of MIL-53(Al). Utilizing a diamond anvil cell as the high-pressure device, we employed in situ Fourier transform infrared spectroscopy to examine the structural changes in activated MIL-53(Al) under compression and its CO 2 adsorption performance under specific simultaneous high-pressure and high-temperature conditions. Our findings reveal that heating serves as an effective strategy to augment CO 2 adsorption by enhancing the mobility of the CO 2 molecules under high pressure. Remarkably, the CO 2 adsorption capacity of MIL-53(Al) surged when subjected to pressures from 0.20 to 1.24 GPa and temperatures up to the melting point of CO 2 . Detailed spectral analysis further elucidated the chemisorptive nature of host–guest interactions between the framework and CO 2 . These findings significantly advance our understanding of MOFs’ potential for carbon capture across a broad pressure–temperature spectrum.