| 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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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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| 4. |
- Liu, Tianqi, et al.
(författare)
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Isolation and Identification of Pseudo Seven-Coordinate Ru(III) Intermediate Completing the Catalytic Cycle of Ru-bda Type of Water Oxidation Catalysts
- 2022
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Ingår i: CCS Chemistry. - : Chinese Chemical Society. - 2096-5745. ; 4:7, s. 2481-2490
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Tidskriftsartikel (refereegranskat)abstract
- Isolation of RuIII-bda (17-electron specie) complex with an aqua ligand (2-electron donor) is challenging due to violation of the 18-electron rule. Although considerable efforts have been dedicated to mechanistic studies of water oxidation by the Ru-bda family, the structure and initial formation of the RuIII-bda aqua complex are still controversial. Herein, we challenge this often overlooked step by designing a pocket-shape Ru-based complex 1. The computational studies showed that 1 possesses the crucial hydrophobicity at the RuV(O) state as well as similar probability of access of terminal O to solvent water molecules when compared with classic Ru-bda catalysts. Through characterization of single-crystal structures at the RuII and RuIII states, a pseudo seven-coordinate “ready-to-go” aqua ligand with RuIII...O distance of 3.62 Å was observed. This aqua ligand was also found to be part of a formed hydrogen-bonding network, providing a good indication of how the RuIII-OH2 complex is formed.
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| 5. |
- Liu, Tianqi, et al.
(författare)
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Promoting Proton Transfer and Stabilizing Intermediates in Catalytic Water Oxidation via Hydrophobic Outer Sphere Interactions
- 2022
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Ingår i: Chemistry - A European Journal. - : Wiley-VCH Verlagsgesellschaft. - 0947-6539 .- 1521-3765. ; 28:24
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Tidskriftsartikel (refereegranskat)abstract
- The outer coordination sphere of metalloenzyme often plays an important role in its high catalytic activity, however, this principle is rarely considered in the design of man-made molecular catalysts. Herein, four Ru-bda (bda=2,2 '-bipyridine-6,6 '-dicarboxylate) based molecular water oxidation catalysts with well-defined outer spheres are designed and synthesized. Experimental and theoretical studies showed that the hydrophobic environment around the Ru center could lead to thermodynamic stabilization of the high-valent intermediates and kinetic acceleration of the proton transfer process during catalytic water oxidation. By this outer sphere stabilization, a 6-fold rate increase for water oxidation catalysis has been achieved.
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| 6. |
- Wang, Zhaohui, et al.
(författare)
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Lightweight, Thin, and Flexible Silver Nanopaper Electrodes for High-Capacity Dendrite-Free Sodium Metal Anodes
- 2018
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Ingår i: Advanced Functional Materials. - : Wiley-Blackwell. - 1616-301X .- 1616-3028. ; 28:48
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Tidskriftsartikel (refereegranskat)abstract
- Owing to its resource-abundant and favorable theoretical capacity, sodium metal is regarded as a promising anode material for sodium metal batteries. However, uncontrolled Na plating/stripping, including Na dendrite growth during cycling, has hindered its practical application. Herein, a sodiophilic, thin, and flexible silver nanopaper (AgNP) is designed based on interpenetrated nanocellulose and silver nanowires and is used as a dendrite-free Na metal electrode. Due to a network of highly conducting silver nanowire (0.6 Ω sq?1, 8200 S cm?1), the sodiophilic nature of silver, and the reduced internal strain within the flexible AgNP, a compact Na metal layer can be uniformly deposited on and reversibly stripped from the AgNP electrode without any observations of Na dendrites during cycling at 1 mA cm?2 for 800 h. As the AgNP electrode is only 2 µm thick, with a low mass loading of 0.88 mg cm?2, the AgNP?Na anode deposited with a Na deposition charge of 6 mAh cm?2 exhibits a capacity of 995 mAh g?1AgNP?Na, approaching that of a Na metal anode (1166 mAh g?1Na). The present approach provides new possibilities for the development of lightweight and stable metal batteries.
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| 7. |
- 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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| 8. |
- 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.
-
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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| 9. |
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| 10. |
- Zhou, Shengyang, et al.
(författare)
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A mechanically robust spiral fiber with ionic-electronic coupling for multimodal energy harvesting
- 2024
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Ingår i: Materials Horizons. - : ROYAL SOC CHEMISTRY. - 2051-6347 .- 2051-6355.
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Tidskriftsartikel (refereegranskat)abstract
- Wearable electronics are some of the most promising technologies with the potential to transform many aspects of human life such as smart healthcare and intelligent communication. The design of self-powered fabrics with the ability to efficiently harvest energy from the ambient environment would not only be beneficial for their integration with textiles, but would also reduce the environmental impact of wearable technologies by eliminating their need for disposable batteries. Herein, inspired by classical Archimedean spirals, we report a metastructured fiber fabricated by scrolling followed by cold drawing of a bilayer thin film of an MXene and a solid polymer electrolyte. The obtained composite fibers with a typical spiral metastructure (SMFs) exhibit high efficiency for dispersing external stress, resulting in simultaneously high specific mechanical strength and toughness. Furthermore, the alternating layers of the MXene and polymer electrolyte form a unique, tandem ionic-electronic coupling device, enabling SMFs to generate electricity from diverse environmental parameters, such as mechanical vibrations, moisture gradients, and temperature differences. This work presents a design rule for assembling planar architectures into robust fibrous metastructures, and introduces the concept of ionic-electronic coupling fibers for efficient multimodal energy harvesting, which have great potential in the field of self-powered wearable electronics. In this work, a concept of ionic-electronic coupling fibers by integrating a 2D MXene and a polymer electrolyte to fabricate spiral metastructures is proposed to realize multimodal power generation from various sources simultaneously.
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| 11. |
- Zhou, Shengyang, et al.
(författare)
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Cellulose Nanofiber @ Conductive Metal–Organic Frameworks for High-Performance Flexible Supercapacitors
- 2019
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Ingår i: ACS Nano. - : American Chemical Society. - 1936-0851 .- 1936-086X. ; 13:8, s. 9578-9586
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Tidskriftsartikel (refereegranskat)abstract
- Conductive metal–organic frameworks (c-MOFs) show great potential in electrochemical energy storage thanks to their high electrical conductivity and highly accessible surface areas. However, there are significant challenges in processing c-MOFs for practical applications. Here, we report on the fabrication of c-MOF nanolayers on cellulose nanofibers (CNFs) with formation of nanofibrillar CNF@c-MOF by interfacial synthesis, in which CNFs serve as substrates for growth of c-MOF nanolayers. The obtained hybrid nanofibers of CNF@c-MOF can be easily assembled into freestanding nanopapers, demonstrating high electrical conductivity of up to 100 S cm–1, hierarchical micromesoporosity, and excellent mechanical properties. Given these advantages, the nanopapers are tested as electrodes in a flexible and foldable supercapacitor. The high conductivity and hierarchical porous structure of the electrodes endow fast charge transfer and efficient electrolyte transport, respectively. Furthermore, the assembled supercapacitor shows extremely high cycle stability with capacitance retentions of >99% after 10000 continuous charge–discharge cycles. This work provides a pathway to develop flexible energy storage devices based on sustainable cellulose and MOFs.
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| 12. |
- Zhou, Shengyang, et al.
(författare)
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Cladophora Cellulose : Unique Biopolymer Nanofibrils for Emerging Energy, Environmental, and Life Science Applications
- 2019
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Ingår i: Accounts of Chemical Research. - : American Chemical Society (ACS). - 0001-4842 .- 1520-4898. ; 52:8, s. 2232-2243
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Forskningsöversikt (refereegranskat)abstract
- ConspectusBecause of its natural abundance, hierarchical fibrous structure, mechanical flexibility, potential for chemical modification, biocompatibility, renewability, and abundance, cellulose is one of the most promising green materials for a bio-based future and sustainable economy. Cellulose derived from wood or bacteria has dominated the industrial cellulose market and has been developed to produce a number of advanced materials for applications in energy storage, environmental, and biotechnology areas. However, Cladophora cellulose (CC) extracted from green algae has unprecedented advantages over those celluloses because of its high crystallinity (>95%), low moisture adsorption capacity, excellent solution processability, high porosity in the mesoporous range, and associated high specific surface area. The unique physical and chemical properties of CC can add new features to and enhance the performance of nanocellulose-based materials, and these attributes have attracted a great deal of research interest over the past decade.This Account summarizes our recent research on the preparation, characterization, functionalization, and versatile applications of CC. Our aim is to provide a comprehensive overview of the uniqueness of CC with respect to material structure, properties, and emerging applications. We discuss the potential of CC in energy storage, environmental science, and life science, with emphasis on applications in which its properties are superior to those of other nanocellulose forms. Specifically, we discuss the production of the first-ever paper battery based on CC. This battery has initiated a rising interest in the development of sustainable paper-based energy storage devices, where cellulose is used as a combined building block and binder for paper electrodes of various types in combination with carbon, conducting polymers, and other electroactive materials. High-active-mass and high-mass-loading paper electrodes can be made in which the CC acts as a high-surface-area and porous substrate while a thin layer of electroactive material is coated on individual nanofibrils. We have shown that CC membranes can be used directly as battery separators because of their low moisture content, high mesoporosity, high thermal stability, and good electrolyte wettability. The safety, stability, and capacity of lithium-ion batteries can be enhanced simply by using CC-based separators. Moreover, the high chemical modifiability and adjustable porosity of dried CC papers allow them to be used as advanced membranes for environmental science (water and air purification, pollutant adsorption) and life science (virus isolation, protein recovery, hemodialysis, DNA extraction, bioactive substrates). Finally, we outline some concluding perspectives on the challenges and future directions of CC research with the aim to open up yet unexplored fields of use for this interesting material.
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| 13. |
- Zhou, Shengyang, et al.
(författare)
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Drawing Highly Ordered MXene Fibers from Dynamically Aggregated Hydrogels
- 2024
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Ingår i: Nano Reseach. - 1998-0124 .- 1998-0000.
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Tidskriftsartikel (refereegranskat)abstract
- Assembly of two-dimensional (2D) nanomaterials into well-organized architectures is pivotal for controlling their function and enhancing performance. As a promising class of 2D nanomaterials, MXene have attracted significant interest for use in wearable electronics due to their unique electrical and mechanical properties. However, facile approaches for fabricating MXenes into macroscopic fibers with controllable structures are limited. In this study, we present a strategy for easily spinning MXene fibers by incorporating polyanions. The introduction of poly(acrylic acid) (PAA) into MXene colloids has been found to alter MXene aggregation behavior, resulting in a reduced concentration threshold for lyotropic liquid crystal phase. This modification also enhances the viscosity and shear sensitivity of MXene colloids. Consequently, we were able to draw continuous fibers directly from the gel of MXene aggregated with PAA. These fibers exhibit homogeneous diameter and high alignment of MXene nanosheets, attributed to the shear-induced long-range order of the liquid crystal phase. Furthermore, we demonstrate proof-of-concept applications of the ordered MXene fibers, including textile-based supercapacitor, sensor, and electrical thermal management, highlighting their great potential applied in wearable electronics. This work provides a guideline for processing 2D materials into controllable hierarchical structures by regulating aggregation behavior through the addition of ionic polymers.
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| 14. |
- Zhou, Shengyang, et al.
(författare)
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Efficient Solar Thermal Energy Conversion and Utilization by a Film of Conductive Metal–Organic Framework Layered on Nanocellulose
- 2022
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Ingår i: ACS Materials Letters. - : American Chemical Society (ACS). - 2639-4979. ; 4, s. 1058-1064
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Tidskriftsartikel (refereegranskat)abstract
- Developing materials for efficient solar thermal energy conversion (STEC) is currently a promising field in energy research. Traditional STEC materials such as carbon and plasmonic nanomaterials have limited efficiency of solar heat utilization, despite their high photothermal conversion efficiency. This paper describes a film composed of hybrid nanofibers of a metal–organic framework layered on cellulose (MC film), resulting in both high photothermal conversion and heat utilization efficiency. The mechanically strong and flexible film can be designed as a solar-driven actuator, enabling large-angle actuation and high contractile power up to 2.5 times greater than that of human muscle. Furthermore, the gathered heat by a MC film-based apparatus can be manipulated to drive solar steam generation for highly efficient seawater desalination, generating clean water at rate of 2.25 kg m–2 h–1 under one-sun irradiation without surface salt accumulation. This work may provide a design rule for developing high-performance STEC systems.
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| 15. |
- Zhou, Shengyang, et al.
(författare)
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Elastic Aerogels of Cellulose Nanofibers@Metal–Organic Frameworks for Thermal Insulation and Fire Retardancy
- 2020
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Ingår i: Nano-Micro Letters. - : Springer Science and Business Media LLC. - 2150-5551 .- 2311-6706. ; 12:9
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Tidskriftsartikel (refereegranskat)abstract
- Metal–organic frameworks (MOFs) with high microporosity and relatively high thermal stability are potential thermal insulation and flame-retardant materials. However, the difficulties in processing and shaping MOFs have largely hampered their applications in these areas. This study outlines the fabrication of hybrid CNF@MOF aerogels by a stepwise assembly approach involving the coating and cross-linking of cellulose nanofibers (CNFs) with continuous nanolayers of MOFs. The cross-linking gives the aerogels high mechanical strength but superelasticity (80% maximum recoverable strain, high specific compression modulus of ~ 200 MPa cm3 g−1, and specific stress of ~ 100 MPa cm3 g−1).The resultant lightweight aerogels have a cellular network structure and hierarchical porosity, which render the aerogels with relatively low thermal conductivity of ~ 40 mW m−1 K−1. The hydrophobic, thermally stable MOF nanolayers wrapped around the CNFs result in good moisture resistance and fire retardancy. This study demonstrates that MOFs can be used as efficient thermal insulation and flame-retardant materials. It presents a pathway for the design of thermally insulating, superelastic fire-retardant nanocomposites based on MOFs and nanocellulose.
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| 16. |
- Zhou, Shengyang, et al.
(författare)
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Electrochemical Doping and Structural Modulation of Conductive Metal‐Organic Frameworks
- 2024
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Ingår i: Angewandte Chemie International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 63:14
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we introduce an electrochemical doping strategy aimed at manipulating the structure and composition of electrically conductive metal-organic frameworks (c-MOFs). Our methodology is exemplified through a representative c-MOF, Ni3(HITP)2 (HITP=2, 3, 6, 7, 10, 11-hexaiminotriphenylene), synthesized into porous thin films supported by nanocellulose. While the c-MOF exhibits characteristic capacitive behavior in neutral electrolyte; it manifests redox behaviors in both acidic and alkaline electrolytes. Evidence indicates that the organic ligands within c-MOF undergo oxidation (p-doping) and reduction (n-doping) when exposed to specific electrochemical potentials in acidic and alkaline electrolyte, respectively. Interestingly, the p-doping process proves reversible, with the c-MOF structure remaining stable across cyclic p-doping/de-doping. In contrast, the n-doping is irreversible, leading to the gradual decomposition of the framework into inorganic species over a few cycles. Drawing on these findings, we showcase the versatile electrochemical applications of c-MOFs and their derived composites, encompassing electrochemical energy storage, electrocatalysis, and ultrafast actuation. This study provides profound insights into the doping of c-MOFs, offering a new avenue for modulating their chemical and electronic structure, thereby broadening their potential for diverse electrochemical applications.
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| 17. |
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| 18. |
- Zhou, Shengyang, et al.
(författare)
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Highly Crystalline PEDOT Nanofiber Templated by Highly Crystalline Nanocellulose
- 2020
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Ingår i: Advanced Functional Materials. - : John Wiley & Sons. - 1616-301X .- 1616-3028. ; 30:49
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Packing conjugated conducting polymer chains into long-range order can significantly boost their carrier-transport properties, allowing the design and enhancing the performance of applications in next-generation flexible electronics, energy storage, etc. However, strategies for organizing molecular chains have hitherto been challenging and have been associated with poor reprocessability. This paper discusses the development and application of highly crystalline poly(3, 4-ethylenedioxythiophene) (PEDOT) nanofibers. These highly conductive PEDOT nanofibers possess well-defined quasi-one-dimensional topology combined with highly ordered molecular chain arrangements as a result of interface-induced morphological shaping followed by recrystallization induced by Cladophora cellulose. The nanofibers are also easily dispersible and able to be reprocessed in aqueous solution. The multiple functionalities of these PEDOT nanofibers are demonstrated by using them as building blocks for applications such as 1D assembled microfibers in an ultra-sensitive strain sensor, 2D papers for electrochemical energy storage, and 3D aerogels for simultaneous solar-thermal distillation and thermoelectricity generation. The methods discussed here can be the basis of a new avenue for regulating the molecular structure of, processing, and discovering applications for conjugated conducting polymers.
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| 19. |
- Zhou, Shengyang, et al.
(författare)
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Highly Transparent, Flexible, and Mechanically Strong Nanopapers of Cellulose Nanofibers @Metal–Organic Frameworks
- 2019
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Ingår i: Chemistry - A European Journal. - : Wiley. - 0947-6539 .- 1521-3765. ; 25:14, s. 3515-3520
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Tidskriftsartikel (refereegranskat)abstract
- Freestanding nanopapers are fabricated by the assembly of metal-organic frameworks (MOFs) onto cellulose nanofibers (CNFs). The CNFs are wrapped by continuously nucleated MOF layers (CNF@MOF) by interfacial synthesis, the charge density on the surface of the CNFs and the dosage of the surfactant polyvinylpyrrolidone (PVP) being carefully adjusted. The obtained CNF@MOF nanofibers with long-range, continuous, hybrid nanostructures are very different to the composites formed by aggregation of MOF nanoparticles on the substrates. Four typical MOFs (HKUST-1, Al-MIL-53, Zn-MOF-74, ZIF-CO3-1) are successfully grown onto CNFs in aqueous solutions and further fabricated into freestanding nanopapers. Because of the unique nanostructures and morphologies, the corresponding flexible nanopapers exhibit hierarchical meso-micropores, high optical transparency, high thermal stability, and high mechanical strength. A proof-of-concept study shows that the CNF@MOF nanopapers can be used as efficient filters to separate volatile organic compounds (VOCs) from the air. This work provides a new path for structuring MOF materials that may boost their practical application.
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| 20. |
- Zhou, Shengyang
(författare)
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Nanocellulose and Metal-Organic Framework-Based Composites : Synthesis, Characterization, and Applications
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Nanocellulose is one of the most promising of the green materials available for use in a sustainable economy because of its natural abundance and renewability. Compared to petroleum‒derived synthetic polymers, nanocellulose has many unparalleled advantages such as its unique nanofibrous structure, high thermal stability, mechanical flexibility, rich surface chemistry, biocompatibility, and biodegradability. The tremendous potential of nanocellulose has recently been realised in its use as a building block substrate for multifunctional applications such as energy storage devices, flexible electronic devices, and advanced filtration units. In future, more insight will be gained into the fundamental structure−function relationships of nanocellulose‒based functional materials, with subsequent advantages for the materials industry.Metal–organic frameworks (MOFs) are an emerging family of coordination polymers with unique crystalline porous features. Because of their diverse design principles and facile chemical synthesis processes, thousands of MOFs are currently under development. MOFs have found huge application value in many fields, including gas separation and storage, energy storage, industrial catalysis, and so on. However, control of the microscopic dimensions and crystal alignments of MOFs remains a big challenge. The insolubility and brittleness of MOF crystals have also resulted in problems with shaping and processing these substances. These problems have restricted the broader application of MOFs. This thesis explores the concept of nano‒composition with a focus on a previously little explored pathway for processing MOFs with the assistance of Cladophora cellulose (CC) extracted from green algae. Firstly, interfacial synthesis was developed through collaborative coordination of metal ions between the carboxyls on CC and the ligands in MOFs (Paper I). This approach enabled the continuous growth of MOF crystals along the CC to form core–shell hybrid CC@MOF nanofibers. These nanofibers were processable in aqueous solution, enabling facile fabrication of various bulk materials such as films (Paper I) and aerogels (Paper II). The CC@MOF composites had hierarchical porosity, good mechanical flexibility, low thermal conductivity, and high thermal stability. Various applications of the CC@MOF composites have subsequently been demonstrated; these include thermal insulation and fire retardancy (Paper II), electrochemical energy storage (Paper III), photothermal conversion evaporation for efficient water desalination (Paper IV), and solar‒driven ionic power generation (Paper V). This thesis covers the synthesis, structural characterization, and proof‒of‒concept applications of the CC@MOF composites, providing a basic understanding of the relationships between the structure and performance of composite materials.
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| 21. |
- Zhou, Shengyang, et al.
(författare)
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Solar-driven ionic power generation via a film of nanocellulose @ conductive metal-organic framework
- 2021
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry. - 1754-5692 .- 1754-5706. ; 14:2, s. 900-905
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Tidskriftsartikel (refereegranskat)abstract
- Solar energy fits well with the increasing demand for clean sustainable energy. This paper describes a freestanding hybrid film composed of a conductive metal-organic framework layered on cellulose nanofibres which enables efficient solar power generation. The working principle, which is different from the mechanisms of traditional photovoltaic or solid-state thermoelectric generation systems, is based on ionic thermophoresis and electrokinetic effects. Given the strong light absorption and low thermal conductivity of the film, a large thermal gradient can be produced on the surface under light illumination to induce fast water evaporation in an aqueous electrolyte. The thermal gradient and the water evaporation drive selective ion transport through the charged nanochannels, which generates ionic thermoelectric and streaming potentials, respectively. The assembled device can produce a sustained voltage output of ~1.1 V, with a high power density of up to 15 W m-2 under one sun illumination. This study provides a new route for solar power generation.
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| 22. |
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