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1.
    
The covalent organic frameworks (COFs) possessing high crystallinity and capability to capture low-concentration CO2 (400 ppm) from air are still underdeveloped. The challenge lies in simultaneously incorporating high-density active sites for CO2 insertion and maintaining the ordered structure. Herein, a structure engineering approach is developed to afford an ionic pair-functionalized crystalline and stable fluorinated COF (F-COF) skeleton. The ordered structure of the F-COF is well maintained after the integration of abundant basic fluorinated alcoholate anions, as revealed by synchrotron X-ray scattering experiments. The breakthrough test demonstrates its attractive performance in capturing (400 ppm) CO2 from gas mixtures via O─C bond formation, as indicated by the in situ spectroscopy and operando nuclear magnetic resonance spectroscopy using 13C-labeled CO2 sources. Both theoretical and experimental thermodynamic studies reveal the reaction enthalpy of ≈−40 kJ mol−1 between CO2 and the COF scaffolds. This implies weaker interaction strength compared with state-of-the-art amine-derived sorbents, thus allowing complete CO2 release with less energy input. The structure evolution study from synchrotron X-ray scattering and small-angle neutron scattering confirms the well-maintained crystalline patterns after CO2 insertion. The as-developed proof-of-concept approach provides guidance on anchoring binding sites for direct air capture (DAC) of CO2 in crystalline scaffolds.  相似文献   

2.
    
With ever-increasing efforts to design sorbent materials to capture carbon dioxide from flue gas and air, this perspective article is provided based on nearly a decade of collaboration across science, engineering, and industry partners. A key point learned is that a holistic view of the carbon capture problem is critical. While researchers can be inclined to value their own fields and associated metrics, often, key parameters are those that enable synergy between materials and processes. While the role of water in the chemisorption of CO2 is well-studied, in this perspective, it is hoped to highlight the often-overlooked but critical role of water in assessing the potential of a physical adsorbent for CO2 capture. This is a challenge that requires interdisciplinarity. As such, this document is written for a general audience rather than experts in any specific discipline.  相似文献   

3.
    
Herein, the synthesis of Cu3(HAB)x(TATHB)2-x (HAB: hexaaminobenzene, TATHB: triaminotrihydroxybenzene) is reported. Synthetic improvement of Cu3(TATHB)2 leads to a more crystalline framework with higher electrical conductivity value than previously reported. The improved crystallinity and analogous structure between TATHB and HAB enable the synthesis of Cu3(HAB)x(TATHB)2-x with ligand compositions precisely controlled by precursor ratios. The electrical conductivity is tuned from 4.2 × 10−8 to 2.9 × 10−5 S cm−1 by simply increasing the nitrogen content in the crystal lattice. Furthermore, computational calculation supports that the solid solution facilitates the band structure tuning. It is envisioned that the findings not only shed light on the ligand-dependent structure–property relationship but create new prospects in synthesizing multicomponent electrically conductive metal-organic frameworks (MOFs) for tailoring optoelectronic device applications.  相似文献   

4.
    
Photoresponsive covalent organic frameworks (PCOFs) have emerged as attractive candidates for adsorption, but it is challenging to construct PCOF adsorbents due to structural order loss of covalent organic frameworks (COFs) after introducing photoresponsive motifs and/or tedious steps of postmodification. Here, a facile strategy is developed, by dispersing photoresponsive metal-organic polyhedra (PMOP) into COFs, to endow COFs with photoresponsive adsorption sites. As a proof-of-concept study, a COF with pore size of 4.5 nm and PMOP with suitable molecular size (4.0 and 3.1 nm for trans and cis configuration, respectively) are selected to meet the requirements of proper accommodation space, good guest dispersion, and free isomerization. The structure of COF is well preserved after introducing PMOPs. Interestingly, the obtained photoresponsive host–guest composite (PHGC) adsorbents exhibit photomodulated adsorption capacity on propylene (C3H6) and the change in adsorption capacity can reach up to 43.3% and is stable during multiple cycles. Density functional theory calculations reveal that visible-light irradiation drives the azobenzene motifs in PHGCs to the trans configuration and the adsorption sites are fully open and interact with C3H6. UV-light irradiation makes the azobenzene motifs transform to the cis configuration, leading to the shield of the adsorption sites and the consequent release of C3H6.  相似文献   

5.
金属有机骨架材料(MOFs)因具有超高比表面积、较大的孔隙率、多样化且可调的孔道结构及相对温和的制备条件等优势,目前已成为化学和材料等学科的研究热点之一。概述了MOFs材料的制备方法及其用于气体(含碳、含氮及含硫)吸附与分离方面的研究进展,并对其在该方面今后的发展趋势和应用前景进行了展望。  相似文献   

6.
CO2捕获,尤其低浓度CO2捕获,对人类在限域空间中长时间工作、降低天然气液化过程中CO2腐蚀及冻结效应极为重要.本文首次报道了一种具有一维孔道的ZU-16-Co(TIFSIX-3-Co)材料,该材料孔道中含大量电负性F原子,可实现400–10,000 ppm浓度下CO2的高效捕获.相比同构材料,孔径为3.62?的ZU...  相似文献   

7.
    
Direct removal of carbon dioxide (CO2) from the atmosphere, known as direct air capture (DAC) is attracting worldwide attention as a negative emission technology to control atmospheric CO2 concentrations. However, the energy-intensive nature of CO2 absorption-desorption processes has restricted deployment of DAC operations. Catalytic solvent regeneration is an effective solution to tackle this issue by accelerating CO2 desorption at lower regeneration temperatures. This work reports a one-step synthesis methodology to prepare monodispersed carbon nanospheres (MCSs) using trisodium citrate as a structure-directing agent with acidic sites. The assembly of citrate groups on the surface of MCSs enables consistent spherical growth morphology, reduces agglomeration and enhances water dispersibility. The functionalization-assisted synthesis produces uniform, hydrophilic nanospheres of 100–600 nm range. This work also demonstrates that the prepared MCSs can be further functionalized with strong Brønsted acid sites, providing high proton donation ability. Furthermore, the materials can be effectively used in a wide range of amino acid solutions to substantially accelerate CO2 desorption (25.6% for potassium glycinate and 41.1% for potassium lysinate) in the DAC process. Considering the facile synthesis of acidic MCSs and their superior catalytic efficiency, these findings are expected to pave a new path for energy-efficient DAC.  相似文献   

8.
    
Nanocomposites containing Ni or Co or NiCo alloy and nitrogen-doped carbon with diverse ratios have been prepared and utilized as active elements in supercapacitors. The atomic contents of nitrogen, nickel, and cobalt have been adjusted by the supplement amount of Ni and Co salts. In virtue of the excellent surface groups and rich redox active sites, the NC/NiCo active materials exhibit superior electrochemical charge-storage performances. Among these as-prepared active electrode materials, the NC/NiCo1/1 electrode performs better than other bimetallic/carbon electrodes and pristine metal/carbon electrodes. Several characterization methods, kinetic analyses, and nitrogen-supplement strategies determine the specific reason for this phenomenon. As a result, the better performance can be ascribed to a combination of factors including the high surface area and nitrogen content, proper Co/Ni ratio, and relatively low average pore size. The NC/NiCo electrode delivers a maximum capacity of 300.5 C g−1 and superior capacity retention of 92.30% after 3000 unceasing charge-discharge cycles. After assembling it into the battery-supercapacitor hybrid device, a high energy density of 26.6 Wh kg−1 (at 412 W kg−1) is achieved, comparable to the recent reports. Furthermore, this device can also power four light-emitting-diode (LED) demos, suggesting the potential practicability of these N-doped carbon compositing with bimetallic materials.  相似文献   

9.
    
Solid‐state batteries (SSBs) are promising for safer energy storage, but their active loading and energy density have been limited by large interfacial impedance caused by the poor Li+ transport kinetics between the solid‐state electrolyte and the electrode materials. To address the interfacial issue and achieve higher energy density, herein, a novel solid‐like electrolyte (SLE) based on ionic‐liquid‐impregnated metal–organic framework nanocrystals (Li‐IL@MOF) is reported, which demonstrates excellent electrochemical properties, including a high room‐temperature ionic conductivity of 3.0 × 10‐4 S cm‐1, an improved Li+ transference number of 0.36, and good compatibilities against both Li metal and active electrodes with low interfacial resistances. The Li‐IL@MOF SLE is further integrated into a rechargeable Li|LiFePO4 SSB with an unprecedented active loading of 25 mg cm‐2, and the battery exhibits remarkable performance over a wide temperature range from ?20 up to 150 °C. Besides the intrinsically high ionic conductivity of Li‐IL@MOF, the unique interfacial contact between the SLE and the active electrodes owing to an interfacial wettability effect of the nanoconfined Li‐IL guests, which creates an effective 3D Li+ conductive network throughout the whole battery, is considered to be the key factor for the excellent performance of the SSB.  相似文献   

10.
    
Adsorption, storage, and conversion of gases (e.g., carbon dioxide, hydrogen, and iodine) are the three critical topics in the field of clean energy and environmental mediation. Exploring new methods to prepare high-performance materials to improve gas adsorption is one of the most concerning topics in recent years. In this work, an ionic liquid solution process (ILSP), which can greatly improve the adsorption kinetic performance of covalent organic framework (COF) materials for gaseous iodine, is explored. Anionic COF TpPaSO3H is modified by amino-triazolium cation through the ILSP method, which successfully makes the iodine adsorption kinetic performance (K80% rate) of ionic liquid (IL) modified COF AC4tirmTpPaSO3 quintuple compared with the original COF. A series of experimental characterization and theoretical calculation results show that the improvement of adsorption kinetics is benefited from the increased weak interaction between the COF and iodine, due to the local charge separation of the COF skeleton caused by the substitution of protons by the bulky cations of ILs. This ILSP strategy has competitive help for COF materials in the field of gas adsorption, separation, or conversion, and is expected to expand and improve the application of COF materials in energy and environmental science.  相似文献   

11.
    
The “block‐on‐plate” nanocomposite structure material is realized with the zeolitic imidazolate framework (ZIF‐67) on graphene oxide (GO) with surface oxygen‐rich functional groups. Scanning electron microscopy, X‐ray photoelectron spectroscopy, X‐ray diffractograms, fourier transform infrared spectroscopy, and ZIF‐67/GO demonstrate a high capability of promoting the lubricating performance of [Choline][Proline] ([CH][P]) bio‐ionic liquid. Specifically, the wear volume of the disc by [CH][P]‐0.1 ZIF‐67/GO is only 52% of the one lubricated by pure [CH][P]. Moreover, ZIF‐67/GO shows a long time, high dispersion stability in [CH][P]. In addition, the combination of GO nanosheets and ZIF‐67 can make ZIF‐67/GO have better polishing effect between the steels during the friction process, which can effectively form a robust lubrication layer and improves overall lubricating properties. As a result, the interfacial lubrication can be significantly improved by these newly developed [CH][P]‐ZIF‐67/GO lubricants. This work offers a new promising application for ZIF‐67 nanocomposites with GO in advanced lubrication systems. This work also provides a new strategy of producing lubricants containing nanoparticles with high dispersion stability, which may solve the biggest challenge in this field.  相似文献   

12.
金属-有机骨架(MOF)是一种多孔、高比表面积的新型纳米材料.离子液体(IL)具有稳定性好、功能可设计的特点,将IL负载到MOF的孔中,实现离子液体和MOF材料的有效组合,开发新型功能化复合多孔材料,有利于充分发挥两种材料的优势.本文主要介绍IL/MOF复合材料合成方法、分子模拟及其应用的最新研究.总结目前IL/MOF...  相似文献   

13.
    
Water splitting technology can convert renewable energies such as solar and wind into hydrogen energy, which is key to achieving a low-carbon hydrogen economy cycle. However, Pt-based catalysts for hydrogen evolution reaction (HER) are too expensive, thus it needs to develop efficient non-noble metal catalysts as alternatives. Herein, Ni-BDC-loaded carbon cloth (CC) is co-pyrolyzed with urea to obtain a composite structure of carbon nanotubes (CNT) and porous carbon (PC) embedded with W-doped Ni nanoparticles on CC, resulting in NiW-CNT/PC/CC. Benefiting from the synergistic effect between Ni and W, the high conductivity of CNT, and the high mass transfer rate of PC, NiW-CNT/PC/CC exhibits excellent HER activity in KOH, which only requires a low overpotential of 45 mV to drive a current density of 10 mA cm−2 with stability exceeding 40 h. Simulation calculations confirm that the W doping in metal Ni can optimize its electronic structure by lowering the d-band center and weakening hydrogen adsorption, thus reducing its HER barrier.  相似文献   

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15.
    
Nanoscale metal-organic frameworks (NMOFs) have attracted increased attention in recent years for miniaturized and/or biological applications.However,the synthesis of ultrasmall NMOFs with good stability is a great challenge.In this study,sub-5-nm nano-HKUST-1 was prepared for the first time via a mild metalorganic gel route without surfactants or capping agents.Controlling the gelation process via anion-ligand self-assembly is the key to the formation of NMOFs.The Tyndall effect,zeta potential,and liquid adsorption indicated strong stability of the obtained nano-HKUST-1,even in water.Adsorption experiments were performed using different dyes (crystal violet and methylene blue) to demonstrate the size-dependent adsorption thermodynamics and kinetics of this famous MOF.The results of this study provide new insights regarding the synthesis of NMOFs and their efficient applications.  相似文献   

16.
    
Silicon (Si) anode suffers from huge volume expansion which causes poor structural stability in terms of electrode material, solid electrolyte interface, and electrode, limiting its practical application in high-energy-density lithium-ion batteries. Rationally designing architectures to optimize the stress distribution of Si/carbon (Si/C) composites has been proven to be effective in enhancing their structural stability and cycling stability, but this remains a big challenge. Here, metal-organic frameworks (ZIF-67)-derived carbon nanotube-reinforced carbon framework is employed as an outer protective layer to encapsulate the inner carbon-coated Si nanoparticles (Si@C@CNTs), which features dual carbon stress-buffering to enhance the structural stability of Si/C composite and prolong their cycling lifetime. Finite element simulation proves the structural advantage of dual carbon stress-buffering through significantly relieving stress concentration when Si lithiation. The outer carbon framework also accelerates the charge transfer efficiency during charging/discharging by the improvement of lithium-ion diffusion and electron transport. As a result, the Si@C@CNTs electrode exhibits excellent long-term lifetime and good rate capability, showing a specific capacity of 680 mAh g−1 even at a high rate of 1 A g−1 after 1000 cycles. This work provides insight into the design of robust architectures for Si/C composites by stress optimization.  相似文献   

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18.
在这项工作中,制备了一种以金属有机配位聚合物(MOFs)材料(HKUST-1)为载体,通过KCoFC(Co(NO3)2与K4Fe(CN)6反应产物)功能化修饰后的新型复合材料,并通过FTIR、SEM、XRD对其进行表征。研究初始Cs+浓度、吸附时间、溶液pH值对吸附效果的影响,用吸附动力学和吸附等温线模型研究HKUST-1/KCoFC对Cs+的吸附过程。实验表明:在40 min内,Cs+吸附量迅速增加,复合材料对Cs+吸附量最佳的pH为8;HKUST-1/KCoFC对Cs+吸附过程符合准二级动力学和Langmuir模型。  相似文献   

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