Facile synthesis and characterization of CuCl@MIL‐101(Cr)‐NH₂ framework for carbon monoxide adsorption

Abstract

The development of a highly efficient CO‐selective adsorbent with high CO adsorption and selectivity is a challenging task. In this work, a novel adsorbent CuCl@MIL‐101(Cr)‐NH2 [Cu(I)@MIL‐101(Cr)‐NH2] with varied Cu(I) loads was fabricated for CO adsorption. An equimolar mixture of CuCl2 and Cu(HCOO)2 was first impregnated into MIL‐101(Cr)‐NH2 host, followed by reduction at a low temperature of 150 oC. The obtained material was characterized by XRD, FT‐IR, XPS, FE‐SEM, TGA, and N2 sorption methods. CO adsorption experiments revealed that the Cu(I)@MIL‐101(Cr)‐NH2 showed considerably improved CO‐adsorbing capacity owing to the formation of π‐complex between Cu+ and CO. At 25 oC and 100 kPa, the prepared adsorbent contained 30 wt% of CuCl exhibited a maximum CO uptake capacity of ~2.40 mmol.g‐1, exceeding many other Cu(I)‐containing adsorbents that used conventional host materials, such as CuCl/γ‐Al2O3, CuCl/MCM‐41, CuZSM‐5, Cu(I)‐loaded porous organic polymer, CuCl/AlOOH, and CuCl@γ‐Al2O3. Furthermore, Cu(I)@MIL‐101(Cr)‐NH2 exhibited a higher isosteric heat of CO adsorption than MIL101(Cr)‐NH2. The findings suggest that incorporating Cu(I) into metal‐organic frameworks could be a promising strategy for developing CO‐selective materials.