New Ca- and Sr-based coordination polymers (CPs) were mechanochemically synthesized by milling metal hydroxide samples (M = Ca, Sr) with tetrafluorophthalic acid (H2oBDC-F4) and isophthalic acid (H2mBDC). [Ca(oBDC-F4)(H2O)2] (1) exhibits a small surface area which is slightly increased after removing the crystal water. On the other hand, the hydrated sample of the nonfluorinated [Sr(mBDC)(H2O)3.4] (2) reveals a small BET surface area which remains unchanged even after the release of crystal water via thermal treatment. The new compounds 1 and 2 are similar to their Sr- and Ca-analogs, respectively. These findings are confirmed by thermal analysis, MAS NMR, and ATR-IR measurements, in addition to the Le Bail refinements for the measured powder X-ray data of 1 and 2. Ca- and Sr-CPs based on perfluorinated dicarboxylic systems and their nonfluorinated analogs diverse in structural and chemical properties depending on the geometries of the organic linkers and the presence of fluorine atoms. The fluorinations of organic ligands lead to the formation of fluorinated CPs with higher dimensionalities compared to their nonfluorinated counterparts. Conversely, the thermal stabilities of the latter are higher than those of the fluorinated CPs.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1039/c8dt00488a | DOI Listing |
Environ Sci Technol
January 2025
Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environment and Ecology, Jiangnan University, Wuxi 214122, PR China.
Thin-film composite (TFC) membrane has been extensively utilized and investigated for its excellent properties. Herein, we have constructed an active layer (AL) containing cave-like structures utilizing large meniscus interface. Furthermore, the impact of interface structure on the growth process, morphology, and effective surface area of AL has been fully explored with the assistance of sodium dodecyl benzenesulfonate (SDBS).
View Article and Find Full Text PDFDalton Trans
January 2025
Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming, China.
During the oxygen evolution reaction (OER), metal-organic framework (MOF) catalysts undergo structural reorganization, a phenomenon that is still not fully comprehended. Additionally, designing MOFs that undergo structural reconstruction to produce highly active OER catalysts continues to pose significant challenges. Herein, a bimetallic MOF (CoNi-MOF) with carboxylate oxygen and pyridine nitrogen coordination has been synthesized and its reconstruction behavior has been analyzed.
View Article and Find Full Text PDFJ Dent Sci
December 2024
School of Dentistry, College of Oral Medicine, Taipei Medical University, Taipei, Taiwan.
Background/purpose: The accuracy of intraoral scanners (IOSs) plays a crucial role in the success of final restorations in digital workflows. Previous studies have shown that numerous factors affect the accuracy of IOSs. Most studies have evaluated the accuracy of IOS under one restoration condition.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Hunan University, Chemistry and Chemical Engineering, Lushan South Road, Yuelu District, 410082, Changsha, CHINA.
Site density and turnover frequency are the two fundamental kinetic descriptors that determine the oxygen reduction activity of iron-nitrogen-carbon (Fe-N-C) catalysts. However, it remains a grand challenge to simultaneously optimize these two parameters in a single Fe-N-C catalyst. Here we show that treating a typical Fe-N-C catalyst with ammonium iodine (NH4I) vapor via a one-step chemical vapor deposition process not only increases the surface area and porosity of the catalyst (and thus enhanced exposure of active sites) via the etching effect of the in-situ released NH3, but also regulates the electronic structure of the Fe-N4 moieties by the iodine dopants incorporated into the carbon matrix.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
UK Catalysis Hub, Research Complex at Harwell, Science and Technology Facilities Council, Rutherford Appleton Laboratory, OX11 0FA, UK.
Methanol adsorption isotherms of fresh f-ZSM-5 and steamed s-ZSM-5 (Si/Al ≈ 40) are investigated experimentally at room temperature under equilibrium and by grand canonical Monte Carlo (GCMC) simulations with the aim of understanding the adsorption capacity, geometry and sites as a function of steam treatment (at 573 K for 24 h). Methanol adsorption energies calculated by GCMC are complemented by density functional theory (DFT) employing both periodic and quantum mechanics/molecular mechanics (QM/MM) techniques. Physical and textural properties of f-ZSM-5 and s-ZSM-5 are characterised by diffuse reflectance infrared Fourier transformed spectroscopy (DRIFTS) and N-physisorption, which form a basis to construct models for f-ZSM-5 and s-ZSM-5 to simulate methanol adsorption isotherms by GCMC.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!