Fluorine-Induced Electric Field Gradient in 3D Porous Aromatic Frameworks for Highly Efficient Capture of Xe and F-Gases

Abstract

The development of robust and efficient porous adsorbents is essential for capturing xenon (Xe) and perfluorinated electron specialty gases (F-gases) in semiconductor exhaust gases, as toxic and corrosive gases coexist in high-temperature plasma degradation off-gases. Herein, two three-dimensional (3D) fluorinated porous aromatic frameworks (PAFs) with abundant fluorine (labeled PAF-4F and PAF-8F) were synthesized. The two PAFs exhibit high IAST selectivity in capturing Xe and F-gases from semiconductor off-gases, as well as excellent physicochemical stability and reusability, which have been collaboratively verified by single-component gas adsorption and regeneration tests, etc. Density functional theory (DFT) simulation revealed that the entry of strongly electronegative fluorine atoms into PAFs causes localized charge separation on the polymer pore surface, resulting in the preferential adsorption of high-polarizability Xe and F-gases via induced electric field gradients. Systematic studies have sufficiently manifested the great potential of fluorine-functionalized porous materials to effectively capture Xe and F-gases, which provides practical insights into the fabrication of highly stable porous adsorbents for harsh operating conditions.

Amino-Functionalized Microporous MOFs for Capturing Greenhouse Gases CF4 and NF3 with Record Selectivity

“…This is because NH 2 –Ni-MOF possesses a smaller ultra-micropore and stronger affinity to CF 4 molecules, thus leading to higher selectivity. To the best of our knowledge, this selectivity of CF 4 /N 2 (1/9) in NH 2 –Ni-MOF is the highest in all reported porous materials for CF 4 /N 2 separation (Figure e and Table S2), such as PAF-4F (4.68), F-cage (4.04), New-PAF-1 (∼5), and Cu­(peba) 2 (2.25), notably higher than that of the benchmark C-PVDC-600 (18.6) Figure e).…”

Machine Learning-Enabled Framework for High-Throughput Screening of MOFs: Application in Radon/Indoor Air Separation

“…It is elucidated that the electron delocalization characteristic of benzene rings may contribute to Rn adsorption because it enhances van der Waals forces , between Rn and MOFs via the increment of induced dipoles. The DFT calculation for Xe and Kr gases conducted by Zhang et al , determined that electrostatic potential at the location of aromatic ring sites is relatively high, making it easy for noble gases to generate dipole–dipole interactions, as shown in Figure .…”

Long‐Cycle‐Life Cathode Materials for Sodium‐Ion Batteries toward Large‐Scale Energy Storage Systems

“…Zhang et al investigated the effects of Mg doping on Na 3.12 Fe 2.44 (P 2 O 7 ) 2 . [154] The introduction of Mg 2+ could increase the inherent conductivity of the Na 3.12 Fe 2.44 (P 2 O 7 ) 2 material and facilitate the formation of a uniform and robust CEI during cycling, resulting in excellent rate performance and stable cycling performance. Capacity retention of 79.1% was maintained in Mg-doped Na 3.12 Fe 2.44 (P 2 O 7 ) 2 after 3000 cycles, as well as excellent high-temperature electrochemical performance (95.3% capacity retention after 400 cycles at 60 °C).…”