A novel approach to prepare Cu(I)Zn@MIL-100(Fe) adsorbent with high CO adsorption capacity, CO/CO2 selectivity and stability via controlled host–guest redox reaction

Overview of Carbon Monoxide Adsorption Performance of Pristine and Modified Adsorbents

“…It was also observed that Ni 2+ increased the CO adsorption capacity even when solely impregnated in MIL-101(Cr), as shown in Figure 9b. Although Zn 2+ alone had a negligible effect on the the adsorption capacity, Zn 2+ showed a synergistic effect on the reduction of Cu 2+ (CuZn/ MIL100Fe (78) in Figure 9 and Table 5). 78 As discussed in section 3.3, Fe 2+ can act as a reducing agent.…”

“…When a Cu 2+ precursor is used, metals can be coimpregnated to facilitate the conversion of Cu 2+ to Cu + . 77,78,95 Specific impregnation methods, such as dry impregnation, wet impregnation, and double-solvent (DS) methods, are applied to load the copper component on the supporting porous material (step 2). The wet impregnation method is a conventional metal impregnation method.…”

“…Recently, transition metals such as Ni 2+ , Zn 2+ , Fe 2+ , Mn 2+ , and Co 2+ have been coimpregnated with Cu 2+ species in MOFs, and their effects are summarized in Table 5. 77,78,95 When Ni 2+ , Zn 2+ , Fe 2+ , Mn 2+ , and Co 2+ were selected as additives for MIL-101(Cr), 95 the order of the CO adsorption capacities was as follows: Ni 2+ > Zn 2+ > Fe 2+ > Mn 2+ > Co 2+ (Figure 9 a). It was also observed that Ni 2+ increased the CO adsorption capacity even when solely impregnated in MIL-101(Cr), as shown in Figure 9b.…”

“…In addition, the amount of unsaturated Fe 2+ contributed to increasing the stability at a sufficiently high activation temperature of 523 K. 69 As a result, MIL-100(Fe) adsorbents also showed relatively high CO adsorption capacities of 0.3−1.2 mmol/g among the pristine MOFs (Table S4). 48,53,69,74,75,78 MIL-101(Cr) adsorbents are also widely used for CO adsorption because of their large S BET and high hydrothermal stability. According to theoretical calculations using the generalized gradient approximation with dispersion-corrected density functional theory (DFT-D), CO adsorption occurs by charge transfer from CO to Cr as the strongest interaction along with four Lewis acid−Lewis base interactions between chemicals and CO. 93 As shown in Table 4, MIL101Cr(48) had a lower CO adsorption capacity at 101.3 kPa than MIL100Fe (48), which had a lower S BET , because of the contributions to CO adsorption by unsaturated Fe ions, weak acid surfaces, and smaller pore size.…”

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

“…The Cu(I)-loaded MOF adsorbents are reportedly highly efficient in selective adsorption toward CO. Very recently, Nhieu et al [11] fabricated bimetallic Cu(I)Zn(II)loaded MIL-100(Fe), showing high CO adsorption performance. Researches indicated that the use of MOF-based materials for loading Cu(I) could be a promising strategy for developing highly efficient CO-selective adsorbents.…”