APPLIED THERMAL ENGINEERING
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2020
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IF 4.725
Xiaoxiao Xia,Zhilu Liu,Song Li
Adsorption-driven heat pumps (AHPs) powered by low-grade waste heat and solar energy are promising to reduce the energy consumption for cooling and heating. Seeking novel high-performing adsorbents of AHPs is the key to improve their cooling/heating performance. Very recently, the potential use of covalent-organic frameworks (COFs) adsorbents of AHPs has won increasing research interests. However, the adsorption cooling/heating performance of COFs under varying working conditions is still unexplored. In this study, COF-5 was synthesized and tested to obtain the adsorption isotherms of ethanol working fluid. For comparison, three commonly used metal-organic frameworks (MOFs), including Cu-BTC, MIL-101(Cr), and ZIF-8, were also investigated. The cooling/heating performance of COF-5/ethanol and MOF/ethanol working pairs was evaluated by mathematical modelling based on the basic thermodynamic cycle of AHPs. The results demonstrated that COF-5 with the high coefficient of performance for cooling/heating (COP C /COP H ) under wide temperature lift (ΔT lift ) outperformed MOFs, especially for cooling.
研究领域:
材料科学
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能源工程
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DOI
高影响因子
ChemSusChem
·
2022
·Vol. 15
·期 7
·e202200184
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IF 9.14
Siyong Ou,Min Zhou,Wen Chen,Yuyao Zhang,Yueli Liu
Graphical Photocatalytic CO 2 reduction : A COF-5/CoAl-layered double hydroxide (LDH) heterojunction photocatalyst is developed for the CO 2 reduction reaction. CoAl-LDH incorporation enhances the visible-light response-ability of the photocatalyst and improves the separation efficiency of photogenerated electron–hole pairs through the role of a type-II heterojunction. Photocatalytic conversion of CO 2 into value-added chemical fuels is an attractive route to mitigate global warming and the energy crisis. Reasonable design of optical properties and electronic behavior of the photocatalyst are essential to improve their catalytic activity. Herein, the 1D/2D heterojunction by direct in-situ synthesis of the covalent organic framework (COF)-5 colloid on the surface of CoAl layered double hydroxide (LDH) was used as the prospective photocatalyst for CO 2 reduction. COF-5/CoAl-LDH nanocomposite achieved 265.4 μmol g −1 of CO with 94.6 % selectivity over CH 4 evolution in 5 h under visible light irradiation, which was 4.8 and 2.3 times higher than those of COF-5 colloid and CoAl-LDH, respectively. The enhanced catalytic activity was derived from the increased visible-light activity and the construction of type II-2 heterojunction, which greatly optimized visible light harvesting and accelerated the efficient separation of the photoinduced holes and electrons. This work paves the way for rational design of heterojunction catalysts in photocatalytic CO 2 reduction.
研究领域:
材料科学
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环境科学
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化学
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DOI
PubMed
高影响因子
LANGMUIR
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2025
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IF 3.9
Junting Dong,Guoliang Zhang,Fucong Liu,Houjun Qi,Kan Xing
COF-5 is an excellent choice as a lubricant additive due to its high specific surface area and regular layer stacking structure. In this paper, the porous covalent organic frameworks of the COF-5 nanomaterial were successfully synthesized as a lubricant additive via a method of sonochemical synthesis. Pure [BMIM][SCN] (BS) was used as the base oil, and the tribological properties of the COF-5-BS composite lubricant were evaluated by using a ball-on-disk wear tester. The results were demonstrated that the wear volume of BS with the addition of 0.1 wt % COF-5 was reduced by 46.64% as compared to that of the pure BS, and the corrosion on the friction interface was effectively inhibited by the addition of COF-5 nanomaterial. This phenomenon was ascribed to COF-5 with a large specific surface area, being adsorbed onto the friction interface, which could repair the wear-induced pits and prevent the direct contact between the metal substrate and the corrosive medium. The tribological properties of the COF-5-BS composite lubricant could be efficiently regulated under the applied electric current. The results of intelligent electric current-controlled friction were indicated that the average coefficients of friction (COF) under the current stimulation of 30 mA with on/off cycling were reduced by 12.05% as compared to that of a continuous current operated for 1 h. Moreover, the wear volume and depth were reduced by 11.69% and 8.75%, respectively. That is because the short duration of current regulation could enhance the rapid formation of a lubricant film composed of BS liquid and COF-5 nanosheets on the friction interface. Meanwhile, the temperature on the interface would not be high to produce the failure of lubricating film, resulting in an excellent low friction coefficient and excellent antifriction property.
研究领域:
材料科学
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摩擦学
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表面工程
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DOI
PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2024
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IF 8.1
Ting He,Shanshan Zhang,Yang Zhu,Jiangwei Chen,Xiaoyun Wang,Qingguo Li,Rizhi Chen,Wenbo Pei,Xin Chen,Haibao Duan,Zhaoliang Cui
Extracorporeal CO 2 removal (ECCO 2 R) is a type of extracorporeal life support (ECLS) technology. It aims to remove carbon dioxide (CO 2 ) from small flow of the blood and correct hypercapnia and related acidosis. The ECCO 2 R system removes CO 2 retained in the patient’s body through the gas-blood exchange membranes, which in use, blood flows on the outside of the membrane, and the inside of the membrane is for gas flow. Existing ECCO 2 R system generally improves the emission rate of CO 2 by the increase of the gas flow rate. However, there is a problem that O 2 is simultaneously taken out, which will reduce the blood O 2 concentration. Therefore, the gas-blood exchange membranes should not only increase the CO 2 removal rate by the improvement of CO 2 /O 2 selectivity, but also retain more O 2 in the blood and then maintain the oxygen saturation of the blood. In present work, a method was proposed to fabricate COF-5/Pebax mixed matrix membranes (MMMs) on the PMP surface for enhancing CO 2 /O 2 selectivity, which was increased from 0.96 to 5.57. The CO 2 removal ability of COF-5/Pebax MMM was tested by blood circulation, and it was found that the CO 2 removal effect was increased 10.9% than that of the pristine membranes. The O 2 concentration was maintained at a higher level, about 1.69 times that of the pristine membranes. In contrast to the pristine PMP membrane, blood compatibility of COF-5/Pebax MMMs was improved because protein adhesion decreased by 44.75%. The results of cytotoxicity test and rabbit pyrogen test exhibited that the prepared COF-5/Pebax MMM presented great biosafety. Overall, the proposed COF-5/Pebax MMM has good performance in ECCO 2 R system and attractive potential for medical application.
研究领域:
生物医学工程
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材料科学
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医疗器械
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产品关联
DOI
高影响因子
JOURNAL OF CHROMATOGRAPHY A
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2016
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IF 3.926
Tao Bao,Pingxiu Tang,Deying Kong,Zhenkun Mao,Zilin Chen
Covalent-organic frameworks (COFs) are attractive materials for their fascinating properties, such as rigid structures, exceptional thermal stabilities, low densities, and permanent porosity with specific surface areas, which indicate potential for application in chromatography similar to related metal-organic frameworks (MOFs). However, the utilization of COFs in analytical chemistry is far behind as compared to that of the MOFs due to the challenging work of their immobilization. Here, we have successfully demonstrated the growth of the boron COF-5 on the inner wall of the fused silica capillary by a developed polydopamine-supported method. Combined with the layer-by-layer strategy, multilayer COF-5-coated capillary was obtained. The formation of COF-5 on polydopamine-coated substrate has been confirmed by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction. A novel stationary phase of COF-5 was developed on the basis of successful growth of COF-5 on polydopamine for open-tubular capillary electrochromatography (OT-CEC). Baseline separation of neutral, acidic and basic analytes was achieved on multilayer COF-5-coated capillary column. The fabricated capillary columns showed high column efficiency (154,060 plates/m for methylbenzene), excellent stability and repeatability. The precision (relative standard deviation (RSD), n = 3) of retention time, peak height, and peak area for tested neutral compounds were in the range of 1.2–1.3%, 1.8–4.2%, and 0.9–2.4%, respectively. To the best of our knowledge, it was the first demonstration that COF-5 was developed as a novel stationary phase.
研究领域:
分析化学
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材料科学
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产品关联
DOI
PubMed
高影响因子
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