Mixed monomer derived porous aromatic frameworks with superior membrane performance for CO2 capture

Advanced Porous Aromatic Frameworks: A Comprehensive Overview of Emerging Functional Strategies and Potential Applications

Porous aromatic frameworks (PAFs) are a fundamental group of porous materials characterized by their distinct structural features and large surface areas. These materials are synthesized from aromatic building units linked by strong carbon-carbon bonds, which confer exceptional rigidity and long-term stability. PAFs functionalities may arise directly from the intrinsic chemistry of their building units or through the postmodification of aromatic motifs using well-defined chemical processes. Compared to other traditional porous materials such as zeolites and metallic-organic frameworks, PAFs demonstrate superior stability under severe chemical treatments due to their robust carbon-carbon bonding. Even in challenging environments, the chemical stability and ease of functionalization of PAFs demonstrate their flexibility and specificity. Research on PAFs has significantly expanded and accelerated over the past decade, necessitating a comprehensive overview of key advancements in this field. This review provides an in-depth analysis of the recent advances in the synthesis, functionalization, and dimensionality of PAFs, along with their distinctive properties and wide-ranging applications. This review explores the innovative methodologies in PAFs synthesis, the strategies for functionalizing their structures, and the manipulation of their dimensionality to tailor their properties for specific potential applications. Similarly, the key application areas, including batteries, absorption, sensors, CO2 capture, photo-/electrocatalytic usages, supercapacitors, separation, and biomedical are discussed in detail, highlighting the versatility and potential of PAFs in addressing modern scientific and industrial challenges.

Advances in CO2 separation from the landscape of porous aromatic framework-based engineered membranes

Uncontrolled carbon emission contributes significantly towards global warming and climate change necessitating an urgent and effective remedy. CO2 is one of the major constituents of the greenhouse gas family. The main sources that contribute to CO2 emission are industries, transports, etc., where CO2 gets emitted with other gases. Before released into the environment, effective separation of CO2 from mixture gases can lessen its direct environmental exposure. Traditional techniques for CO2 separation include adsorption, absorption, cryogenic distillation, and membrane separation. Membrane technology is advantageous in CO2 separation due to its excellent properties like energy efficiency, affordability, durability, scalability, processing simplicity, and high separation efficiency. Advancements in membrane materials have introduced various advanced materials among which porous aromatic frameworks (PAFs) are proven highly applicable in gas separation. PAFs are a branch of engineered porous materials that offer excellent porosity, substantial surface area, homogeneous pore size, room for structural modification, and anti-aging properties. PAF-based membranes are widely used in various CO2 separation applications; mostly in natural gas purification and flue gas treatment. This review article has discussed synthetic routes of PAFs, structural modification techniques, membrane applications, and mechanisms in the context of CO2 separation. The current status of PAF-based membranes is briefly highlighted from an economic and industrial point of view. Future directions for PAF-based membranes such as functionalization or integration of PAFs with other materials/nanomaterials to create hybrid materials with greater CO2-phillicity are discussed. Moreover, potential aspects to consider in the near future associated with PAF syntheses are also highlighted.

Donor-acceptor type triphenylamine-based porous aromatic frameworks (TPA-PAFs) for photosynthesis of benzimidazoles

The development of efficient and recyclable photocatalysts for organic synthesis is of great interest. This study presents the synthesis of triphenylamine-based porous aromatic frameworks (TPA-PAFs) in an alternating donor-acceptor (D-A) manner. The light absorption range and the optical band gaps of TPA-PAFs are effectively tuned by changing the electron acceptor units, which further determine their photocatalytic properties. As a result, TPA-PAFs exhibit excellent catalytic performance for the photosynthesis of benzimidazoles in high yields (up to 99%), broad substrate scope (18 examples), and good recyclability (up to 10 cycles). This work provides a feasible approach toward the facile design and synthesis of efficient and stable PAF-based photocatalysts, which further broadens the application of PAFs catalytic materials in photocatalytic organic synthesis.