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Although the catalytic activity is heavily reliant on the electronic structure of the catalyst, understanding the impact of electron spin regulation on electrocatalytic performance is still rarely investigated. This work presents a novel approach involving the single‐atom coordination of cobalt (Co) within metalloporphyrin‐based three‐dimensional covalent organic frameworks (3D‐COFs) to facilitate the catalytic conversion for sodium‐iodine batteries. The spin state of Co is modulated by altering the oxidation state of the porphyrin‐centered Co, achieving optimal catalysis for iodine reduction. Experimental results demonstrate that CoII and CoIII are incorporated into the 3D‐COFs, exhibiting spin ground states of S=1/2 and S=0, respectively. The low spin state of CoIII is favorable to hybridize with the sp 3d orbitals of I3−, thus facilitating the conversion of I3− to I−. Density‐functional theory (DFT) calculations further reveal that the presence of CoIII enhances iodide adsorption and accelerates the formation of NaI in 3D‐COFs‐CoIII, thereby promoting its rapid kinetic behaviors. Notably, the I2@3D‐COFs‐CoIII cathode achieves a high reversible capacity of 227.7 mAh g−1 after 200 cycles at 0.5 C and demonstrates exceptional cyclic stability, exceeding 2000 cycles at 10 C with a minor capacity fading rate of less than one 0.01 % per cycle. [ABSTRACT FROM AUTHOR]

• New [OH] x -BD-TFPM 3D-COFs with pore surface engineering was proposed. • Content-tunable OH groups on channel walls significantly promoted OA capture. • Hydrophobic and hydrophilic multiple groups realized high adsorption performance. • LOD of 0.005 μg/kg was exhibited for OA detection using 3D-COF coupled with LC-MS. • Accurate analysis of OA in shellfish was achieved with good recovery yields. A novel three-dimensional covalent organic framework (3D-COF) with content-tunable and active hydroxyl groups (OH) on the pore walls was developed and adopted for the high-performance capture of okadaic acid (OA) marine toxins. Using pore-surface engineering, the integration of linear building blocks (4,4′-diamino-3,3′-biphenyldiol, BD(OH) 2 and benzidine, BD) with the 3D structural building block backbone (4,4′,4′',4′''-methane-tetrayltetrabenzaldehyde, TFPM) was achieved. By adjusting the ratio of BD(OH) 2 , functional multicomponent-COFs [OH] x -BD-TFPM COFs (X = 25%) were synthesized, which offered ideal access to convert a conventional COF into a functional platform with multiple-mode interactions of hydrophobic and hydrophilic groups for OA capture. [OH] x -BD-TFPM was characterized using SEM, XRD, FT-IR, and BET. The adsorption features and analytical performance of OA were screened and evaluated. Optimization of dispersive solid-phase extraction using [OH] 25 -BD-TFPM was accomplished, and the method was verified for sensitive quantitative detection of OA in clam and mussel samples. Coupled with LC-MS/MS, the resultant [OH] 25 -BD-TFPM COF demonstrated the ability to analyze OA, and the limit of detection for OA in shellfish was determined to be 0.005 μg/kg. A significant improvement in trace OA detection was observed compared to previously reported SPE materials without adjustable hydrophilic interactions. The recoveries of OA in the fortified clam and mussel samples were in the ranges of 93.9‒105.1% and 96.7‒110.2%, respectively. This study highlights that OH-group surface engineering in channel walls is a facile and powerful strategy for developing functional 3D-COFs with multiple interactions for high-performance target capture. [ABSTRACT FROM AUTHOR]

[Display omitted] • Three-dimensional COFs was first introduced into the field of Th (IV) separation. • The adsorption capacity of COF-DL229 is higher than reported two-dimensional COF. • COF-DL229 exhibits excellent selectivity for Th (IV) compared to other materials. • The interaction mechanism was explored by characterizations and DFT calculations. A novel porous material tailored for Th (IV) entrapment with not only large capacity but also high selectivity is highly desired for the thorium fuel cycle. Here, a three-dimensional COF (covalent organic framework) material, named COF-DL229 was prepared for the efficiently selective entrapment of Th (IV). Batch sorption experiments indicated that the entrapment of Th (IV) was a pH-dependent, rapid (equilibrium was reached within 1 min) process. The maximum saturated entrapment capacity could reach 513 mg g−1, which is higher than that of the reported two-dimensional COF. The single-component batch experiments and muti-components dynamic experiments suggested that COF-DL229 has a strong affinity towards Th (IV), but little affinity with other ions, which makes COF-DL229 a promising material for selective thorium recovery from waste solution. The interaction mechanism was Th-N coordination, which was confirmed by characterizations (Fourier Transform infrared spectroscopy, FT-IR, X-ray photoelectron spectroscopy, XPS, energy dispersive spectrometer, EDS) and density functional theory (DFT) calculations. The density of states indicated that the doping of the Th (IV) can lower the band gap of the COF-DL229, indicating higher electrical conductivity and stronger adsorption energy. The differential charge exhibited an obvious charge transfer between Th (IV) and the N atom in COF-DL229. [ABSTRACT FROM AUTHOR]

• A novel three-dimensional covalent organic frameworks (3D COFs) TpTAM coated open-tubular capillary column was developed in a simple method. • Good separation of fluoroquinolones were achieved and the TpTAM-coated columns exhibited excellent reproducibility and stability. • This research expands the application of 3D COFs as stationary phases in CEC for antibiotic chromatographic separation. The Schiff-base reaction of 1,3,5-triformylphloroglucinol (Tp) and tetra(4-aminophenyl)methane (TAM) was performed for the synthesis of a three-dimensional covalent organic framework named 3D TpTAM, which was obtained by an ultrasound-assisted method for the first time. The morphology and structure of the synthesized TpTAM were characterized through various methods. Then, TpTAM-coated capillary columns were subsequently prepared by a covalent bonding method within a short time and applied for the separation of fluoroquinolones by capillary electrochromatography (CEC) with good resolution and reproducibility. The intraday relative standard deviations (RSDs) of the retention time and peak areas were 0.88%–0.95% and 2.27%–3.81%, respectively. The interday RSDs of retention time and peak areas were 0.71%–0.89% and 0.88%–3.60%, respectively. The column-to-column RSDs of retention time and peak areas were less than 1.90% and 13.56%, respectively. The interbatch RSDs of retention time and peak areas were less than 3.48% and 3.89%, respectively. The TpTAM-coated capillary columns could be used for no less than 100 runs with no observable changes in the separation efficiency. The separation mechanism was also studied, which indicated that π-π stacking effects, hydrophobic interactions and hydrogen bonding were the main factors. The results revealed that 3D TpTAM should have superior potential as the stationary phase in CEC for chromatographic separation. [ABSTRACT FROM AUTHOR]