Highly efficient mechanochemical synthesis of an indium based metal-organic framework with excellent water stability

- An indium based metal-organic framework InOF-1 was successfully synthesized by mechanochemical method in 20 min.
- InOF-1 retains its structure and porosity after being soaked in water for 12 h.
- InOF-1 has not only high CO2 adsorption capacity of 4.03 mmol/g at 273 K and 100 kPa but also high CO2/CH4 and CO2/N2 adsorption selectivities.

Mechanochemical synthesis, induced by mechanical grinding, is demonstrated to be rapid and efficient for metal-organic frameworks (MOFs) synthesis. For this purpose, a mechanochemical synthesis route was proposed for the first time for preparation of water stable indium metal-organic frameworks InOF-1. The effects of preparation conditions such as the addition of solvents and grinding time were discussed, and the InOF-1 synthesized through optimized condition was used to investigate its selective CO2 adsorption. Results showed that using liquid-assisted grinding for 20 min with CH3CN (0.4 mL) could lead to highly crystalline and porous InOF-1 with a Brunauer-Emmett-Teller (BET) surface area of 707 m2/g. The addition of a small amount of solvent into the system could dramatically improve the crystallinity and porosity of InOF-1. More importantly, the synthesized product with the highest specific surface area retained its crystallinity and porosity after being soaked in water for 12 h. Its CO2 adsorption capacity reached as high as 4.03 mmol/g at 273 K and 100 kPa, and CO2/CH4 and CO2/N2 adsorption selectivities were up to 7.5 and 45, respectively. The superior performance of the mechanochemically synthesized InOF-1 makes it a potential candidate for CO2 adsorption and separation.

195