Pore Size Modulation in Flexible Metal-Organic Framework Enabling High Performance Gas Sensing

Pore size plays a critical role in determining the performance of metal-organic frameworks (MOFs) in catalysis, sensing, and gas storage or separation. However, revealing the pore-size/property relationship remains extremely challenging because ideal structure models possessing different pore sizes but having the same components are lacking. In this work, a solvent-coordination directed structure swelling method was developed for modulating the ratio between the large and narrow pore phases of a flexible MOF, MIL-88B. Pore-size-dependent gas sensitivity and selectivity were studied for the first time in the MIL-88B samples. The optimized MIL-88B-20 % sample showed one of the best sensing performances among all the reported MOF-based H2S-sensing materials. This work not only provides a method to synthesize ideal structure models for revealing the relationship between pore-size and properties, but also may inspire the development of high-performance gas sensing materials.

Automated summary

Pore size is crucial in determining the performance of metal-organic frameworks (MOFs) in various applications. However, the relationship between pore size and properties is difficult to study due to the lack of ideal structure models. In this work, a method was developed to modulate the ratio between large and narrow pore phases in a flexible MOF, MIL-88B. Gas sensitivity and selectivity dependent on pore size were studied, and the optimized MIL-88B-20% sample showed excellent sensing performance. This study not only provides a method to synthesize ideal structure models for studying the relationship between pore size and properties, but also inspires the development of high-performance gas sensing materials.