| 1. |
- Afewerki, Samson, et al.
(författare)
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Combined Catalysis for Engineering Bioinspired, Lignin-Based, Long-Lasting, Adhesive, Self-Mending, Antimicrobial Hydrogels
- 2020
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 14:12, s. 17004-17017
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Tidskriftsartikel (refereegranskat)abstract
- The engineering of multifunctional biomaterials using a facile sustainable methodology that follows the principles of green chemistry is still largely unexplored but would be very beneficial to the world. Here, the employment of catalytic reactions in combination with biomass-derived starting materials in the design of biomaterials would promote the development of eco-friendly technologies and sustainable materials. Herein, we disclose the combination of two catalytic cycles (combined catalysis) comprising oxidative decarboxylation and quinone-catechol redox catalysis for engineering lignin-based multifunctional antimicrobial hydrogels. The bioinspired design mimics the catechol chemistry employed by marine mussels in nature. The resultant multifunctional sustainable hydrogels (1) are robust and elastic, (2) have strong antimicrobial activity, (3) are adhesive to skin tissue and various other surfaces, and (4) are able to self-mend. A systematic characterization was carried out to fully elucidate and understand the facile and efficient catalytic strategy and the subsequent multifunctional materials. Electron paramagnetic resonance analysis confirmed the long-lasting quinone-catechol redox environment within the hydrogel system. Initial in vitro biocompatibility studies demonstrated the low toxicity of the hydrogels. This proof-of-concept strategy could be developed into an important technological platform for the eco-friendly, bioinspired design of other multifunctional hydrogels and their use in various biomedical and flexible electronic applications.
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| 2. |
- Kong, Xueying, et al.
(författare)
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All-cellulose-based freestanding porous carbon nanocomposites and their versatile applications
- 2022
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Ingår i: Composites Part B. - : Elsevier. - 1359-8368 .- 1879-1069. ; 232
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Tidskriftsartikel (refereegranskat)abstract
- Porous carbons are key functional materials in a range of industrial processes such as gas adsorption and separation, water treatment, and energy conversion and storage. It is, however, important from a sustainability perspective for porous carbons to be synthesized from naturally abundant biopolymers. Nanoengineering of porous carbons using facile binder-free techniques presents significant challenges, but is deemed beneficial for broadening their field of use and improving their application performance. This paper discusses the processing of cellulose-based porous carbons interwoven with cellulose nanofibers to fabricate freestanding nanopapers and aerogels, aiming at developing processable, fully sustainable, and all-cellulose-based carbon nanocomposites. The aerogels, which have cellular networks, low density and high mechanical strength, were investigated as sorbents for CO2 capture and removal of various organics. The presence of rich ultramicropores allows the aerogels to adsorb relatively high amounts of CO2, with high selectivity of CO2-over-N-2 (up to 111). More importantly, the sorbents have high CO2 working capacities and excellent recyclability under temperature swing adsorption conditions. In addition, the aerogels can adsorb various organic solvents remarkably well, corresponding to 100-217 times their own weight. The nanopapers are active photothermal materials that can be applied as solar absorbers for interfacial solar vapor generation, providing a high evaporation rate (1.74 kg m(-2) h(-1) under one sun illumination). The nanopapers were also employed as electrodes in flexible, foldable super capacitors with high areal capacitances. This study may provide a basis for further development of and new application areas for all-cellulose-based nanocomposites.
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| 3. |
- Kong, Xueying, et al.
(författare)
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Ambient Aqueous Synthesis of Imine-Linked Covalent Organic Frameworks (COFs) and Fabrication of Freestanding Cellulose Nanofiber@COF Nanopapers
- 2023
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 146:1, s. 742-751
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Tidskriftsartikel (refereegranskat)abstract
- Covalent organic frameworks (COFs) are usually synthesized under solvothermal conditions that require the use of toxic organic solvents, high reaction temperatures, and complicated procedures. Additionally, their insolubility and infusibility present substantial challenges in the processing of COFs. Herein, we report a facile, green approach for the synthesis of imine-linked COFs in an aqueous solution at room temperature. The key behind the synthesis is the regulation of the reaction rate. The preactivation of aldehyde monomers using acetic acid significantly enhances their reactivity in aqueous solutions. Meanwhile, the still somewhat lower imine formation rate and higher imine breaking rates in aqueous solution, in contrast to conventional solvothermal synthesis, allow for the modulation of the reaction equilibrium and the crystallization of the products. As a result, highly crystalline COFs with large surface areas can be formed in relatively high yields in a few minutes. In total, 16 COFs are successfully synthesized from monomers with different molecular sizes, geometries, pendant groups, and core structures, demonstrating the versatility of this approach. Notably, this method works well on the gram scale synthesis of COFs. Furthermore, the aqueous synthesis facilitates the interfacial growth of COF nanolayers on the surface of cellulose nanofibers (CNFs). The resulting CNF@COF hybrid nanofibers can be easily processed into freestanding nanopapers, demonstrating high efficiency in removing trace amounts of antibiotics from wastewater. This study provides a route to the green synthesis and processing of various COFs, paving the way for practical applications in diverse fields.
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| 4. |
- Kong, Xueying, et al.
(författare)
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Aqueous synthesis and engineering of imine-linked covalent organic frameworks
- 2023
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Ingår i: One-day symposium: Sorption, Transport and Catalysis in Metal-Organic Frameworks. Uppsala 18/9 2023. - Uppsala.
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Konferensbidrag (refereegranskat)abstract
- Covalent organic frameworks (COFs) are typically synthesized through solvothermal methods, which necessitate the use of hazardous organic solvents, elevated reaction temperatures, and intricate procedures. Additionally, their insolubility and inability to melt present substantial challenges in the processing of COFs. In this study, we present an eco-friendly method for synthesizing imine-linked COFs by simply stirring the initial materials in an aqueous solution at room temperature. A key element of this approach involves the pre-activation of aldehyde monomers using acetic acid, significantly enhancing their reactivity in aqueous solutions. This innovative strategy results in the rapid formation of highly crystalline COFs formed at relatively high yields, with substantial surface areas, within minutes. Remarkably, this method performs exceptionally well on a gram-scale, producing highly crystalline and porous COFs in scaled-up reactions.We successfully synthesized a total of 15 COFs using monomers with diverse molecular sizes, geometries, pendant groups, and core structures, underscoring the versatility of this approach. Furthermore, our use of cellulose nanofibers (CNFs) as a substrate during the syntheses allows for the growth of COF nanolayers on the CNF surface. These CNF@COF hybrid nanofibers can be effortlessly transformed into freestanding nanopapers.Significantly, both COF powders and CNF@COF nanopapers exhibit remarkable efficiency in removing trace amounts of antibiotics from wastewater. This research offers a promising avenue for the green synthesis and processing of various COFs, paving the way for practical applications in diverse fields.
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| 5. |
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| 6. |
- Kong, Xueying, 1993-
(författare)
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Porous Materials and Their Cellulose-Based Composites : Synthesis, Nanoengineering, and Applications
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Porous materials, such as porous carbons (PCs), metal-organic frameworks (MOFs), and covalent organic frameworks (COFs), show considerable potential across various fields because of their rich microporous and mesoporous structures and large surface areas, yet they grapple with challenges like environmentally unfriendly fabrication methods and poor processability. In this thesis, we investigated environmentally friendly fabrication methods for porous materials, nanoengineering techniques for processing these materials, and their potential applications.Cladophora cellulose (CC), a naturally abundant biopolymer, was used to prepare PC via a one-step physical carbonization/activation method without using any corrosive activation agents. The obtained CC-derived PC (CPC) showed a high specific surface area (507.2 m2 g−1) and rich microporous structure. Additionally, we introduced a simple and environmentally friendly method for synthesizing imine-linked COFs at room temperature using water as the solvent. The method involves a key step in which aldehyde monomers are pre-activated by acetic acid, which promotes the aldehyde monomers to dissolve in water, enhancing their reactivity with amine monomers, and ensuring the formation of crystalline COFs. Consequently, we synthesized 16 distinct imine-linked COFs with high crystallinity and specific surface areas. Furthermore, this thesis focusses on improving the poor processability of these materials caused by the infusible and insoluble nature of their powders. The poor processability of these porous materials makes them difficult to process into desired structures and shapes. Here, we introduce two nanoengineering methods: i) Interweaving porous materials with CC nanofibers (CNFs) to form CNF-porous material aqueous solutions; and ii) Interfacial synthesis of porous materials on the surface of carboxylated CNFs to form CNF@porous materials with nanofiber structures in aqueous solutions. The obtained composite suspensions can be fabricated into freestanding and flexible composite nanopapers via a vacuum filtration and drying process. In addition, they can be processed into freestanding aerogels through a freeze-drying process. Consequently, we have successfully prepared freestanding and flexible CC-CPC nanopapers and CC-CPC aerogels, c-CNT@COF/CNT/CNF nanopapers (c-CNT: carboxylated carbon nanotube), CNF@MOF nanopapers, and CNF@COF nanopapers and demonstrated their potential in various applications, from efficient CO2 capture and organic pollutant removal to advanced energy storage and solar vapor generation. In summary, we used environmentally friendly methods to synthesize PC and imine-linked COFs, circumventing the need for corrosive chemical agents and toxic organic solvents, respectively. Furthermore, by combining CNFs with porous materials, we successfully created freestanding and flexible nanopapers and aerogels, thereby addressing the issue of poor processability associated with porous materials.
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| 7. |
- Kong, Xueying, et al.
(författare)
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Redox active covalent organic framework-based conductive nanofibers for flexible energy storage device
- 2021
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Ingår i: Carbon. - : Elsevier BV. - 0008-6223 .- 1873-3891. ; 171, s. 248-256
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Tidskriftsartikel (refereegranskat)abstract
- Covalent organic frameworks (COFs) constitute a family of crystalline porous polymers that are being studied for electrochemical energy storage. However, their low electrical conductivity and poor processability have largely limited their electrochemical performances and practical applications. Here, we develop an interfacial synthesis method to grow few-layered 2D redox-active COFs (DAAQ-TFP COF) on the surface of carboxylated carbon nanotubes (c-CNTs) in order to fabricate core-shell c-CNT@COF nanofibers, for which the thickness and the morphology of the COF nanolayers can be finely controlled. When using the c-CNT@COFs as electrode material, the tailored nanostructure with high electrical conductivity allows efficient electron transfer, while the few-layered structure of the COF promotes fast electrolyte ion diffusion in the near-surface region, which results in an efficient utilization of the redox active sites in COF. More significantly, c-CNT@COFs with nanofibrous structure show good processability and can be assembled into freestanding and flexible nanopapers with the assistance of Cladophora cellulose. Given the good electrochemical performance and excellent flexibility, the nanopaper electrodes are assembled into flexible hybrid capacitors, showing high areal capacitance and extremely long lifetime. This study provides a new pathway for the development of next generation sustainable and flexible energy storage devices based on COFs and cellulose materials.
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| 8. |
- Kong, Xueying, et al.
(författare)
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Synthesis of Porous Organic Polymers with Tunable Amine Loadings for CO2 Capture : Balanced Physisorption and Chemisorption
- 2019
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Ingår i: Nanomaterials. - : MDPI. - 2079-4991. ; 9:7
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Tidskriftsartikel (refereegranskat)abstract
- The cross-coupling reaction of 1,3,5-triethynylbenzene with terephthaloyl chloride gives a novel ynone-linked porous organic polymer. Tethering alkyl amine species on the polymer induces chemisorption of CO2 as revealed by the studies of ex situ infrared spectroscopy. By tuning the amine loading content on the polymer, relatively high CO2 adsorption capacities, high CO2-over-N2 selectivity, and moderate isosteric heat (Qst) of adsorption of CO2 can be achieved. Such amine-modified polymers with balanced physisorption and chemisorption of CO2 are ideal sorbents for post-combustion capture of CO2 offering both high separation and high energy efficiencies.
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| 9. |
- Xu, Chao, et al.
(författare)
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Interweaving metal-€“organic framework-templated Co-€“Ni layered double hydroxide nanocages with nanocellulose and carbon nanotubes to make flexible and foldable electrodes for energy storage devices
- 2018
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Ingår i: Journal of Materials Chemistry A. - 2050-7488. ; 6:47, s. 24050-24057
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Tidskriftsartikel (refereegranskat)abstract
- Metal–organic frameworks (MOFs) and nanocellulose represent emerging and traditional porous materials, respectively. The combination of these two materials in specific ways could generate novel nanomaterials with integrated advantages and versatile functionalities. This study outlines the development of hierarchical porous and conductive nanosheets based on zeolitic imidazolate framework-67 (ZIF-67, a Co-based MOF)-templated Co–Ni layered double hydroxide (LDH) nanocages, Cladophora cellulose (CC) nanofibers, and multi-walled carbon nanotubes (CNTs). The LDH–CC–CNT nanosheets can be used as flexible and foldable electrodes for energy storage devices (ESDs). The electrodes are associated with a high areal capacitance of up to 1979 mF cm−2 at a potential scan rate of 1 mV s−1. A flexible, foldable, and hybrid ESD is assembled from LDH–CC–CNT and CC–CNT electrodes with a PVA/KOH gel. The entire device has an areal capacitance of 168 mF cm−2 and an energy density of 0.6 mW h cm−3 (60 μW h cm−2), at a power density of 8.0 mW cm−3 (0.8 mW cm−2). These promising results demonstrate the potential of using MOFs and sustainable cellulose in flexible, foldable electronic energy storage devices.
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| 10. |
- Xu, Chao, et al.
(författare)
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Interweaving Metal-organic Frameworks Templated Co-Ni Layered Double Hydroxide Nanocages with Nanocellulose and Carbon Nanotubes as Flexible Electrodes for Solid-State Supercapacitors
- 2018
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Ingår i: Interweaving Metal-organic Frameworks Templated Co-Ni Layered Double Hydroxide Nanocages with Nanocellulose and Carbon Nanotubes as Flexible Electrodes for Solid-State Supercapacitors.
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Konferensbidrag (refereegranskat)abstract
- Metal-organic frameworks (MOFs) and nanocellulose represent emerging and traditional porous materials, respectively. The combination of these two materials in specific ways could generate novel nanomaterials with integrated advantages and versatile functionalities. This study outlines the development of hierarchical porous and conductive nanosheets based on zeolitic imidazolate framework-67 (ZIF-67, a Co-based MOF) templated Co-Ni layered double hydroxide (LDH) nanocages, Cladophora cellulose (CC) nanofibers, and multi-walled carbon nanotubes (CNTs). The strategy relies on evenly interweaving the hollow Co-Ni LDH nanocages with CC nanofibers and CNTs. Benefiting from the flexibility of nanocellulose, the electrochemical activity of the LDH structure, and the high conductivity of CNTs, the LDH-CC-CNT nanosheets can be used as flexible and foldable electrodes for supercapacitors. The electrodes are associated with high areal capacitance of up to 1979 mF cm−2 at a potential scan rate of 1 mV s−1. A flexible, foldable, and all-solid-state asymmetric supercapacitor (ASC) is assembled from LDH-CC-CNT and CC-CNT electrodes with PVA/KOH gel. The entire device has an areal capacitance of 168 mF cm−2 and an energy density of 0.6 mWh cm−3 (60 μWh cm−2), at a power density of 8.0 mW cm−3 (0.8 mW cm−2). These promising results demonstrate the potential of using MOFs and sustainable cellulose in flexible, foldable electronic energy-storage devices.
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