With the rapid development of modern society, environmental problems, including excessive amounts of CO₂ released in the atmosphere, are becoming more and more serious. It is necessary to develop new materials and technologies to reduce pollution. Among them, metal–organic frameworks (MOFs) have shown potential for application in the area of catalysis due to their ultra-high specific surface area, structural versatility, and designability as well as ease of modification and post-synthesis. Herein, we summarize recent research advances by use of MOFs for boosting CO₂ conversion. Furthermore, challenges and possible research directions related to further exploration are also discussed.

Two novel high-nuclearity manganese clusters, [Mn₁₄(BSC4A)₃(tBuPO₃)₆(μ₄-OH)₃Cl(H₂O)(CH₃OH)]·1.5CH₃OH (1) and [Mn₁₆(BSC4A)₃(PhPO₃)₇(HPO₄)(μ₄-OH)₃Cl(H₂O)(CH₃OH)₄]·4.5CH₃OH (2) (H₄BSC4A = p-tert-butylsulfonylcalix[4]arene; tBuPO₃H₂ = tert-butylphosphonic acid; PhPO₃H₂ = phenylphosphonic acid) have been solvothermally obtained and structurally characterized. Crystal structural analyses reveal that the phosphonate ligands have a large influence on the structures of the polynuclear manganese clusters: complex 1 possesses a drum-like Mn^II ₁₄ core, which is constructed from three Mn₄–BSC4A molecular building blocks (MBBs) and six tBuPO₃ ²⁻ ligands and capped by two Mn^II ions; while complex 2 has a diamond-like Mn^II ₁₆ core, which also consists of three Mn₄–BSC4A MBBs, but connected by seven PhPO₃ ²⁻ linkers and a tetrahedral Mn₄ cluster housing a phosphate anion generated in situ. To the best of our knowledge, complex 2 gives the first calixarene-based cluster linked by both organic phosphonate and inorganic phosphate ligands, and also presents the highest nuclearity manganese complex with the H₄BSC4A ligand to date. Magnetic measurements suggest the presence of antiferromagnetic interactions between the adjacent Mn^II spin carriers for both complexes.

Wastewater containing organic dyes has become one of the important challenges in water treatment due to its high salt content and resistance to natural degradation. In this work, a novelty adsorbent, PEI-SMA, was prepared by grafting polyethyleneimine (PEI) onto styrene-maleic anhydride copolymer (SMA) through an amidation reaction. The various factors, such as pH, adsorbent dosage, contact time, dye concentration, and temperature, which may affect the adsorption of PEI-SMA for Reactive Black 5 (RB5), were systematically investigated by static adsorption experiments. The adsorption process of PEI-SMA for RB5 was more consistent with the Langmuir isotherm model and the pseudo-second-order model, suggesting a single-layer chemisorption. PEI-SMA exhibits excellent adsorption performance for RB5 dye, with a maximum adsorption capacity of 1749.19 mg g^–1 at pH = 2. Additionally, PEI-SMA exhibited highly efficient RB5 competitive adsorption against coexisting Cl⁻ and SO₄²⁻ ions and cationic dyes. The adsorption mechanism was explored, and it can be explained as the synergistic effect of electrostatic interaction, hydrogen bonding and π–π interaction. This study demonstrates that PEI-SMA could act as a high performance and promising candidate for the effective adsorption of anionic dyes from aqueous solutions.

A 2-fold interpenetrating Zn-MOF constructed from mixed ligands and a paddle-wheel cluster not only exhibits good IAST selective separation of C ₂ H ₆ /CH ₄ and CO ₂ /N ₂ , but also exhibits good selective detection of Fe ³⁺ , [Co(NH ₃ ) ₆ ] ³⁺ and Cu ²⁺ in water.