The efficient separation of N2O/CO2 using unsaturated Fe2+ sites in MIL-100Fe

Abstract

It is a big challenge to separate N₂O from CO₂ using adsorption because they have similar physical properties. The Fe³⁺–F⁻ site in MIL-100Fe transforms to an unsaturated Fe²⁺ site under high-temperature activation (300 °C), and the target sorbent MIL-100Fe-300 exhibits the biggest difference in CO₂ and N₂O adsorption capacity, and the selectivity of N₂O/CO₂ (50%/50%) is up to 3.00 at 298 K. According to DFT calculations, the original Fe³⁺–F⁻ site has strong interaction with CO₂, but the open Fe²⁺ site has a stronger interaction with N₂O. Through a breakthrough experiment, it was confirmed that MIL-100Fe-300 has the best N₂O/CO₂ separation performance, making it potentially a useful material in industry.