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Developing catalysts with excellent CO2capture capability and electrochemical CO2reduction reaction (CO2RR) at a wide potential range simultaneously is significant but remains a formidable challenge. Here, two novel InMg defective trinuclear cluster-based MOFs (SNNU-41 and SNNU-42) with abundant p-block unsaturated coordinated sites were reported and exhibited good CO2capture and CO2RR performance simultaneously. Due to the suitable micropores, SNNU-41 showed higher CO2capture ability at different adsorption pressure conditions. On account of the rigid framework and the closer pband center to Fermi level, SNNU-42 accelerated the conversion of CO2molecule to C1 efficiency. Notably, via adjusting the ratio of p-block metal (In) in the SNNU-42 framework, the performance of the CO2RR was promoted drastically. SNNU-42 with the InMg (1:1.8) mixed cluster delivered an excellent Faradaic efficiency of 91.3% for C1 products and high selectivity of 72.0% for HCOOH at −2.5 V (vs Ag/Ag+) with a total current density of 77.2 mA cm–2. This work provides a possibility for efficient CO2capture and CO2RR electrocatalysts through the modulation of electronic structures and composition in MOFs.

The construction of superstable metal–organic frameworks (MOFs) for selective gas uptake is urgently demanded but remains a great challenge. Herein, a unique bifunctional deformed [Ga3O(COO)6] inorganic secondary building unit (SBU) generated from the desymmetrical evolution of typical triangular prismatic trinuclear cluster was first introduced, which was extended by an isosceles triangular organic linker to produce a robust Ga-MOF (SNNU-63). Remarkably, SNNU-63can stabilize in water at 25 °C for 96 h and at 80 °C for more than 24 h, which surpasses nearly all other Ga-MOFs. The combined effects of open metal sites and hydrophobic pore environment provided by deformed [Ga3O] SBUs render SNNU-63with high C2H2storage capacity and efficient C2H2and natural gas purification performance. The ideal adsorbed solution theory calculation, column breakthrough tests, and grand canonical Monte Carlo simulations demonstrate that SNNU-63is a potential material for addressing the challenge of C2H2/CO2and C2H2/CH4mixture separation under ambient conditions.

The separation of a mixture of C2H2and CO2is a great challenge due to their similar molecular sizes and shapes. Al-based metal–organic frameworks (Al-MOFs) have great promise for gas separation applications due to their light weight, high stability, and low cost. However, the cultivation of suitable Al-MOF single crystals is extremely difficult and has limited their explorations up to now. Since In, Ga, and Al are all 3p-block metal elements, a systematic application of the periodic law to investigate 3p-MOFs will undoubtedly help in the understanding and development of worthy Al-MOF materials. Herein, we report the design of a robust 3p metal–organic framework platform (SNNU-150) and the systematic regulation of C2H2/CO2separation by open 3p-block metal sites. X-ray single-crystal diffraction analysis reveals that SNNU-150 is a 3,6-connected 3D framework consisting of [M3O(COO)6] trinuclear secondary building units (SBUs) and tritopic nitrilotribenzoate (NTB) linkers. Small {[M3O(COO)6]4(NTB)6} tetrahedral cages and extra-large {[M3O(COO)6]10(NTB)14} polyhedral cages connect with each other to generate a hierarchically porous architecture. These 3p-MOFs present very high water, thermal, and chemical stability, especially for SNNU-150-Al, which can maintain its framework at 85 °C in water for 24 h and in a room-temperature environment for more than 30 days. IAST calculations, breakthrough experiments, and GCMC simulations all show that SNNU-150 MOFs have top-level C2H2/CO2separation performance and follow the order Al-MOF > Ga-MOF > In-MOF.

Evaluating the effect of ligand substitution on metal ions and/or clusters during the MOF growth process is conducive to rational design of isoreticular MOFs with improved performance. Through topological direction and ligand substitution strategy, we herein constructed two Sc-soc-MOFs (Sc-EBTCand Sc-ABTC) based on two similar rectangular-planar diisophthalate ligands, linear-shaped H4EBTC (1,1′-ethynebenzene-3,3′,5,5′-tetracarboxylic acid) and zigzag-shaped H4ABTC (3,3′,5,5′-azobenzenetetracarboxylic acid), under solvothermal conditions with formic acid as a modulator. {Sc[(Sc3O)(H2O)3]3(EBTC)6} (Sc-EBTC) possesses two distinct clusters as SBUs, trinuclear [Sc3O(CO2)6] (SBU1) and mononuclear cluster [ScO6] (SBU2), which maintain the soc-topology except for the mononuclear [ScO6] instead of the corresponding trinuclear [Sc3O(CO2)6] in Sc-ABTC({(Sc3O)(H2O)3(ABTC)1.5(NO3)}). Notably, Sc-EBTCrepresents a rare soc-MOF with two distinct clusters as SBUs. Due to similar pore spaces, the two Sc-soc-MOF materials both exhibit enhanced and comparable gas sorption and selectivity performances. Specially, their remarkable C2H2, C2H4, and CO2storage capacity along with prominent CO2/CH4and C2-hydrocarbons/CH4separations indicate that these Sc-soc-MOFs are promising adsorbents for natural gas purification under ambient conditions.

Comprehensive understanding of substituent groups located on the pore surface of metal–organic frameworks (which we call substituent engineering herein) can help to promote gas adsorption and catalytic performance through ligand functionalization. In this work, pore-space-partitioned metal–organic frameworks (PSP MOFs) were selected as a platform to evaluate the effect of organic functional groups on CO2adsorption, separation, and catalytic conversion. Twelve partitioned acs metal–organic frameworks (pacs-MOFs, named SNNU-25-Rnhere) containing different functional groups were synthesized, which can be classified into electron-donor groups (−OH, −NH2, −CH3, and −OCH3) and electron-acceptor groups (−NO2, −F, −Cl, and −Br). The experimental results showed that SNNU-25-Rnwith electron donors usually perform better than those with electron acceptors for the comprehensive utilization of CO2. The CO2uptake of the 12 SNNU-25-RnMOFs ranged from 30.9 to 183.6 cm3g–1at 273 K and 1 bar, depending on the organic functional groups. In particular, SNNU-25-OH showed the highest CO2adsorption, SNNU-25-CH3had the highest IAST of CO2/CH4(36.1), and SNNU-25-(OH)2showed the best catalytic activity for the CO2cycloaddition reaction. The −OH functionalized MOFs with excellent performance may be attributed to the Lewis acid–base and hydrogen-bonding interactions between −OH groups and the CO2molecules. This work modulated the effect of the microenvironment of MOFs on CO2adsorption, separation, and catalysis in terms of substituents, providing valuable information for the precise design of porous MOFs with a comprehensive utilization of CO2.