Topotactic Synthesis of Phosphabenzene‐Functionalized Porous Organic Polymers: Efficient Ligands in CO 2 Conversion

Synthesis of Vinylene-Linked Thiopyrylium-, Pyrylium-, and Pyridinium-Based Covalent Organic Frameworks by Acid-Catalyzed Aldol Condensation

The development of new vinylene-linked covalent organic frameworks (COFs) with special ionic structure and high stability is challenging. Herein, we report a facile, general method for constructing ionic vinylene-linked thiopyrylium-based COFs from 2,4,6-trimethylpyrylium tetrafluoroborate and other common reagents by means of acid-catalyzed Aldol condensation. Besides, pyrylium-, and pyridinium-based COFs also can be prepared from the same monomer under slightly different reaction conditions. The COFs exhibited uniform nanofibrous morphologies with excellent crystallinities, special ionic structures, well-defined nanochannels, and high specific surface areas.

What Fluorine Can Do in CO2 Chemistry: Applications from Homogeneous to Heterogeneous Systems

CO₂ chemistry including capture and fixation has attracted great attention towards the aim of reducing the consumption of fossil fuels and CO₂ accumulation in the atmosphere. "CO₂ -philic" materials are required to achieve good performance owing to the intrinsic properties of the CO₂ molecule, that is, thermodynamic stability and kinetic inertness. In this respect, fluorinated materials have been deployed in CO₂ capture (physical and chemical pathway) or fixation (thermo- and electrocatalytic procedure) with good performances, including homogeneous (e. g., ionic liquids and small organic molecules) and heterogeneous counterparts (e. g., carbons, porous organic polymers, covalent triazine frameworks, metal-organic frameworks, and membranes). In this Minireview, these works are summarized and analyzed from the aspects of (1) the strategy used for fluorine introduction, (2) characterization of the targeted materials, (3) performance of the fluorinated systems in CO₂ chemistry, and comparison with the nonfluorinated counterparts, (4) the role of fluorinated functionalities in the working procedure, and (5) the relationship between performance and structural/electronic properties of the materials. The systematic summary in this Minireview will open new opportunities in guiding the design of "CO₂ -philic" materials and pave the way to stimulate further progress in this field.

Photocatalytic Reduction of CO2 to CO over Quinacridone/BiVO4 Nanocomposites

Solar energy-driven photoreduction of CO₂ to energy-rich chemicals is of significance for sustainable development but challenging. Herein, quinacridone (QA)/nBiVO₄ (n=0.2-20, in which n stands for the mass ratio of BiVO₄ to QA) nanocomposites were developed for photoreduction of CO₂ . Characterization of the materials with Fourier-transform (FT)IR spectroscopy and X-ray photoelectron spectroscopy (XPS) pointed to QA/nBiVO₄ preparation via hydrogen-bonding-directed self-assembly of QA on BiVO₄ nanosheets. Using triethanolamine (TEOA) as a sacrifice reagent, QA/10BiVO₄ showed the best performance, affording CO with a production rate of 407 μmol g^-1  h^-1 , 24 times higher than those of pure QA. It was indicated that the Z-scheme charge-transfer mechanism of QA/nBiVO₄ could significantly improve the separation and transmission efficiency of photo-generated electrons and holes. This novel approach provides new insight for fabricating the composite photocatalytic materials of small molecule organic semiconductors and inorganic semiconductors with high efficiency for photocatalytic of reduction CO₂ .