Covalent organic frameworks (COFs) have emerged as an important class of organic semiconductors and photocatalysts for the hydrogen evolution reaction (HER)from water. To optimize their photocatalytic activity, typically the organic moieties constituting the frameworks are considered and the most suitable combinations of them are searched for. However, the effect of the covalent linkage between these moieties on the photocatalytic performance has rarely been studied. Herein, we demonstrate that donor-acceptor (D-A) type imine-linked COFs can produce hydrogen with a rate as high as 20.7 mmol g h under visible light irradiation, upon protonation of their imine linkages. A significant red-shift in light absorbance, largely improved charge separation efficiency, and an increase in hydrophilicity triggered by protonation of the Schiff-base moieties in the imine-linked COFs, are responsible for the improved photocatalytic performance.
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http://dx.doi.org/10.1002/anie.202104870 | DOI Listing |
Chem Sci
January 2025
Hunan Key Laboratory of Micro & Nano Materials Interface Science, College of Chemistry and Chemical Engineering, Central South University Changsha 410083 P. R. China
The layer-stacking mode of a two-dimensional (2D) material plays a dominant role either in its topology or properties, but remains challenging to control. Herein, we developed alkali-metal ion-regulating synthetic control on the stacking structure of a vinylene-linked covalent triazine framework (termed spc-CTF) for improving hydrogen peroxide (HO) photoproduction. Upon the catalysis of EtONa in Knoevenagel polycondensation, a typical eclipsed stacking mode (spc-CTF-4@AA) was built, while a staggered one (spc-CTF-4@AB) was constructed using LiOH.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Henan University, Colleg of Chemistry and Molecular Sciences, Jingmin, 475004, Kaifeng, CHINA.
Cycloparaphenylenes (CPPs) represent a significant challenge for the synthesis of mechanically interlocked architectures, because they lack heteroatoms, which precludes traditional active and passive template methods. To circumvent this problem and explore the fundamental and functional properties of CPP rotaxanes and catenanes, researches have resorted to unusual non-covalent and even to labor-intensive covalent template approaches. Herein, we report a ring-in-ring non-covalent template strategy that makes use of the surprisingly strong non-covalent inclusion of crown ethers into suitably sized CPPs.
View Article and Find Full Text PDFRapid Commun Mass Spectrom
April 2025
State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, Hong Kong SAR, China.
Rational: People are widely exposed to parabens in their daily life, but parabens are endocrine disrupting chemicals that pose a threat to human health. Therefore, establishing a rapid screening method to enhance monitoring of parabens is necessary. Herein, a covalent organic framework (COF) nanofilm-assisted laser desorption ionization mass spectrometry (LDI-MS) method was established to screen parabens in personal care products (PCPs).
View Article and Find Full Text PDFFood Chem
December 2024
Institute of Food Safety, Chinese Academy of Inspection and Quarantine, Beijing 100176, China; Key Laboratory of Food Quality and Safety for State Market Regulation, Chinese Academy of Inspection and Quarantine, Beijing 100176, China. Electronic address:
An innovative core-shell covalent organic framework (COF), FeO@COF (ETTBA-ND), was synthesized through a facile and energy-efficient method. This adsorbent facilitated magnetic solid phase extraction (MSPE) of six AFs prior to LC-MS/MS analysis, achieving one-step purification and enrichment in food matrices. The successful synthesis of the adsorbent was confirmed using various techniques, with adsorption capacities ranging from 46.
View Article and Find Full Text PDFJ Hazard Mater
January 2025
State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, PR China; The Key Laboratory of Water and Sediment Sciences, Ministry of Education, School of Environment, Beijing Normal University, Beijing 100875, PR China. Electronic address:
An in situ self-cleaning covalent organic framework featuring arylbiguanide arms (Aryl-BIG-COF) was first developed to remove emerging organic pollutants such as propranolol (PRO) from water. The main breakthroughs addressed the scarcity of functional active sites, the impracticality of ex situ regeneration, and the rapid recombination of electronhole pairs in the application of COFs. Owing to the directional capture ability and electronic structure regulation of the arylbiguanide arms, the adsorption capacity and photocatalytic degradation rate of the newly synthesized COF increased by nearly four and seven times, respectively.
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