Carbon Dioxide Adsorption in Amine‐Functionalized Mixed‐Ligand Metal–Organic Frameworks of UiO‐66 Topology

Abstract

A series of mixed-ligand [1,4-benzenedicarboxylic acid (BDC)/2-amino-1,4-benzenedicarboxylic acid (ABDC)] UiO-66 metal-organic frameworks (MOFs) synthesized through two different methods (low (LT) and high temperature (HT)) have been investigated for their carbon dioxide adsorption properties from 0 to 1 bar to clarify the role of amino loading on carbon dioxide uptake. Volumetric CO2 isotherms show that the CO2 capacity (normalized to the Langmuir surface area) increases with a degree of functionalization of about 46%; for similar NH2 contents, the same values are found for both synthetic procedures. Microcalorimetric isotherms reveal that amino-functionalized materials have a larger differential heat of adsorption (q(diff) ) towards CO2 ; reaching 27(25) and 20(22) kJ mol(-1) on HT(LT)-UiO-66-NH2 and UiO-66, respectively, at the lowest equilibrium pressures used in this study. All experimental results are supported by values obtained through quantum mechanical calculations.

Metal–Organic Gel Material Based on UiO‐66‐NH2 Nanoparticles for Improved Adsorption and Conversion of Carbon Dioxide

“…In addition, the adsorption is far from saturation at 0.1 MPa. Interestingly,t he present adsorptionc apability is 38 %h igher than that reported for the corresponding crystalline MOF UiO-66-NH 2 (68 cm 3 g À1 at 273 K, 0.1 MPa), [11,29] even thoughZ rBDC-NH 2 -1:1-0.2 has as urfacea rea similart ot hat of UiO-66-NH 2 . [8] We suppose that defects (open metal sites) in the present gel material help to improve the CO 2 adsorption capability,a sd ot he high surface area and amino moieties.…”

“…[7][8][9][10] The amino groups of UiO-66-NH 2 significantly enhance CO 2 adsorp-tion. [11,12] UiO-66-NH 2 has high catalytic activity for cycloaddition reactions of CO 2 ,b ecauseb oth acidic and basic sites coexist in close proximity. [13][14][15] Metal-organic gels (MOGs) have recently been developed as anew type of soft materials.…”

When defects turn into virtues: The curious case of zirconium-based metal-organic frameworks

“…Such superior stability has been attributed to the strength of the carboxylate-Zr bond and to the high degree of connectivity of the metal clusters and is extremely attractive for practical applications. These applications include gas sorption/separation [12][13][14][15][16], heterogeneous catalysis [17][18][19][20][21], drug delivery [22][23][24][25][26], sensing [27][28][29][30][31][32] and electrochemistry [33][34][35][36].…”

“…Two types of defects were discovered in Zr-MOFs: missing-linkers and missing-clusters ( Figure 3). replacement of one Zr 6 O 6 (bdc) 12 12unit with twelve monocarboxylic groups, generating one missingcluster defect per unit cell (c). Colour code: ZrO 8 polyhedra, pink O, red; C, grey.…”

Gated Channels and Selectivity Tuning of CO2 over N2 Sorption by Post‐Synthetic Modification of a UiO‐66‐Type Metal–Organic Framework

“…Chemically and thermally stable networks have recently attracted attention in the field of MOF chemistry. The UiO‐66 MOF, a three‐dimensional framework of Zr IV ‐carboxylate clusters, Zr 6 (μ 3 ‐O) 4 (CO 2 ) 12 , and linking 1,4‐benzenedicarboxylate (BDC) 2− units, is characterized by exceptional stability, high adsorption volumes, and good functional‐group tolerance during the MOF synthesis . The surface area of unfunctionalized UiO‐66 was determined to be greater than 1100 m 2 g −1 .…”