Precise Introduction of Single Vanadium Site into Indium-Organic Framework for CO2 Capture and Photocatalytic Fixation.

The capture and fixation of CO2 under mild conditions is a cost-effective route to reduce greenhouse gases, but it is challenging because of the low conversion and selectivity issues. Metal-organic frameworks (MOFs) are promising in the fields of adsorption and catalysis because of their structural tunability and variability. However, the precise structural design of MOFs is always pursued and elusive. In this work, a metal-mixed MOF (SNNU-97-InV) was designed by precisely introducing single vanadium site into the isostructural In-MOF (SNNU-97-In). The single V sites clearly change the interactions between the MOF framework and CO2 molecules, leading to a 71.3% improvement in the CO2 adsorption capacity. At the same time, the enhanced light absorption enables SNNU-97-InV to efficiently convert CO2 into cyclic carbonates (CCs) with epoxides under illumination. Controlled experiments showed that the promoted performance of SNNU-97-InV may be that the V═O site can more easily combine with CO2 and convert them into an intermediate state under illumination, and the possible mechanism was thus speculated.

Design of a Multifunctional Indium-Organic Framework: Fluorescent Sensing of Nitro Compounds, Physical Adsorption, and Photocatalytic Degradation of Organic Dyes.

The detection of nitro compounds and removal of organic dyes remain urgent issues because they are poisonous to humans. Taking advantage of metal-organic framework (MOF) materials, we demonstrate herein an indium-organic framework (InOF) exhibiting sensitive fluorescence sensing of nitro compounds, prominent dye capture, and excellent photodegradation of dyes. By using 4,4',4″-s-triazine-1,3,5-triyltri-p-aminobenzoate (TATAB), an amino-functionalized BTB-like linker, the 3D SNNU-110 structure ({[In3OCl(H2O)2(TATAB)2]}n) is formed. SNNU-110 shows a 3,6-connected 3,6T22 topology with TATAB and [In3O(CO2)6] tricapped trigonal-prismatic clusters as 3- and 6-connected nodes. Thanks to the fluorescence properties and amine recognition sites of TATAB, SNNU-110 exhibits excellent performance of fluorescence quenching for six electron-deficient nitroaromatics. The intercrossing 1D channels in SNNU-110 formed from the a- and b-axis directions with dimensions of about 18 Å × 11 Å can capture diverse cationic, anionic, or neutral dyes effectively. What is more, the existence of an inorganic [In3O] cluster enable SNNU-110 to be a good photocatalyst. Upon irradiation with a 300 W xenon lamp, SNNU-110 shows outstanding photocatalytic activity toward rhodamine B (RhB) and methylene blue (MB), and there was almost no degradation. The catalytic activity can retain about 94.6% (RhB) and 93.1% (MB), respectively. Overall, SNNU-110 fully demonstrates the power of multicomponent MOFs, which provide a feasible route for the design of functional materials toward to pollutant identification and removal applications.

Channel partition into nanoscale polyhedral cages of a triple-self-interpenetrated metal-organic framework with high CO2 uptake.

Reported herein is a novel porous metal-organic framework (MOF) exhibiting unique nanoscale cages derived from the 3-fold self-interpenetration of chiral eta networks based on trifurcate {Zn2(CO2)3} building blocks and 1,3,5-tris(4-carboxyphenyl)benzene ligands. The attractive self-interpenetrated structural features contribute to the highest CO2 uptake capacity and CO2 binding ability among the interpenetrated MOFs.