A sustainable one-pot route for the synthesis of hierarchical porous carbons (HPCs) from cornstalk without pith is developed. Calcium carbonate (CaCO
3
) as a hard template can promote the activation ...process and manipulate the pore structure. The interaction of CaCO
3
and the activating agent (potassium oxalate) gives rise to an etching effect and gasification, which can tailor the porosity of the carbon. The removal of loose and spongy pith can improve the meso/micropore ratio, significantly increasing the electrochemical capacitance and rate capability. The as-prepared cornstalk rind-based hierarchical porous carbon (CRHPC) with an interconnected pore structure exhibits a high capacitance of 461 F g
−1
at 0.5 A g
−1
in 1 M H
2
SO
4
. Meanwhile, it displays good cycling stability, with a high capacitance retention of 90.4% at 10 A g
−1
after 10 000 cycles. Furthermore, the symmetric supercapacitor shows a high energy density of 42.5-33.3 W h kg
−1
at a power density of 0.4-9.3 kW kg
−1
and superior rate capability (78.0% capacitance retention at 20 A g
−1
). The simple removal of loose pith endows the carbon materials with an increased mesopore ratio and graphitization degree, which greatly contribute to rapid ion transportation, low internal resistance and high capacitance and energy density. This low-cost strategy holds great promise in the large-scale production of highly porous carbons from lignocellulose for advanced and efficient energy storage.
A sustainable one-pot route for the synthesis of hierarchical porous carbons (HPCs) from cornstalk without pith is developed.
The application of porous carbon microspheres derived from pure biomass in supercapacitors is restricted due to their limited reactive groups. MXene owns a combination of redox Faradic surface with ...good metallic conductivity and hydrophilicity, which assists to obtain high pseudocapacitance and energy density. Herein, Ti3C2Tx MXene was introduced to chitosan-based porous carbon microsphere (CPCM) to fabricated sandwich-like structure (CPCM/MXene) through electrostatic interaction. The Ti3C2Tx protected the spherical structure of CPCM. Meanwhile, CPCM hindered the reaggregation of Ti3C2Tx by inserting in the Ti3C2Tx layers, promoting the electrolyte migration kinetics. The synergistic effect endowed CPCM/MXene high specific capacitance of 362 F/g at current density of 0.5 A/g and acceptable cycling stability with 93.87% capacitance retention at a high current density of 10 A/g after 10,000 cycles. Furthermore, CPCM/MXene displayed a high energy density of 27.8 W/(h•kg) at 500.0 W/kg of power density. These satisfactory performances prove that combining Ti3C2Tx MXene nanosheets with porous carbon microspheres is a considering method to construct a new generation electrode material of supercapacitor.
Inorganic salts are able to simultaneously control the microstructure and composition of biomass carbon materials; however, researchers always pay attention to the microstructure but ignore the ...composition. In this study, lignin derived hierarchical porous carbons (LHPCs) with embedded carbon quantum dots (CQDs) and a high mesopore ratio were synthesized by a salt template-assisted method, followed by activation. ZnCl
2
/KCl salt was introduced into the hydrothermal process, which acted as a pore padding agent and temperature-conducting medium. As a consequence, the pore structure was optimized, and at the same time the CQDs were protected from re-aggregation, resulting in plentiful accessible storage sites and excellent ion migration ability and stability. Eventually, an integral conductive network was formed, which significantly enhanced the transfer kinetics and capacitance effect. Thus, LHPCs exhibited an ultrahigh meso-porosity of 90.17% and a superior specific capacitance of 458.7 F g
−1
. After 10 000 cycles, they also displayed excellent cycling stability with 103% capacitance retention at a current density of 20 A g
−1
. This method provides a simple and efficient strategy to prepare hierarchical porous carbon for high performance supercapacitors.
Lignin-based hierarchical porous carbon with self-embedded carbon quantum dots for supercapacitor electrodes.
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•Surface functionalization endow MXene with superhydrophobicity and stability.•Superhydrophobic MXene-based composite film (FMX-T) with nanocellulose was prepared.•Sandwich-like ...structure of FMX-T film solves brittleness of MXene-based film.•FMX-T film shows self-cleaning and high photothermal conversion capacity.•FMX-T film achieves light-driven motion and long-lasting antibacterial properties.
Although Ti3C2Tx MXene has been widely investigated for diverse applications due to its excellent performance, it has long faced challenges such as hydrophilicity, oxidation susceptibility and poor mechanical properties. In this work, surface functionalization using perfluorosilane (PFOTS) was applied to endow MXene with super-hydrophobicity, improving its stability, and the resulting materials remained unaltered after at least 150 days. Superhydrophobic composite film with a sandwich-like structure was prepared from superhydrophobic MXene and TEMPO-oxidized nanocellulose through layer-by-layer self-assembly method. The resulting hybrid film exhibits exceptional flexibility and strength, which could be fold into various shapes and easily support a considerable weight (ca. 1 kg). The superhydrophobic composite film displays a high-water contact angle of over 153°, showing excellent self-cleaning ability, water repellency and durability. The composite film also shows high photothermal conversion capacity and stability, being able to rapidly increase the temperature over 100 °C under NIR laser irradiation, maintaining it during long time. Interestingly, the combination of super-hydrophobicity and photothermal conversion ability of the composite film successfully achieves controllable light-driven motion and enhanced antibacterial properties by the simultaneous integration of super-hydrophobicity, antiadhesion and long-lasting photothermal sterilization properties. The resulting multifunctional film not only expands knowledge of superhydrophobic surfaces, but also provides valuable new options and strategies for potential applications in light-sensitive robotics, free-standing flexible electronic solids, and improved antibacterial materials.
Super strength and high barrier properties are the bottleneck of the application of cellulose film materials. Herein, it is reported a flexible gas barrier film with nacre-like layered structure, in ...which 1D TEMPO-oxidized nanocellulose (TNF) and 2D MXene self-assembled to form an interwoven stack structure with 0D AgNPs filling the void space. The strong interaction and dense structure endowed TNF/MX/AgNPs film with mechanical properties far superior to PE films and acid-base stability. Importantly, the film presented ultra-low oxygen permeability confirmed by molecular dynamics simulations and better barrier properties to volatile organic gases than PE films. It is here considered the tortuous path diffusion mechanism of the composite film responsible for the enhanced gas barrier performance. The TNF/MX/AgNPs film also possessed antibacterial properties, biocompatibility and degradability (completely degraded after 150 days in soil). Collectively, the TNF/MX/AgNPs film brings innovative insights into the design and fabrication of high-performance materials.
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•The TNF/MX/AgNPs barrier film with a nacre-like layered structure was prepared.•The film showed excellent mechanical strength and could withstand a weight of 1 kg.•Dense structure gave the film ultra-low O2 permeability compared to PE film.•The film had better barrier properties to several organic volatiles than PE film.•The film possessed excellent antibacterial property and biodegradability.
Carbon-based aerogels are difficult to accomplish satisfactory mechanical strength and fatigue resistance due to the brittleness of framework, limiting their application in piezoresistive sensors. In ...this work, inspired by tracheid structure in plants, flexible piezoresistive sensors were prepared based on stable and elastic carbon-based aerogels with a long-range oriented multiscale matrix structure. The carbon-based aerogel was generated by bidirectional freezing and further assembled to i) 2D morphology Ti3C2Tx MXene as conductive framework and ii) cellulose nanofibers (CNF) offering abundant hydroxyl groups as flexible substrate. Besides, positively charged chitosan was introduced to serve as “bridging junction reinforcement element”, which tightly connects CNF and Ti3C2Tx, contributing to improved strength and stability of the carbon-based aerogel. According to finite element simulation, the bonding and supporting effect of chitosan is confirmed, and the aligned carbon layer and elastic supporting microstructure can be directly modulated. Interestingly, the piezoresistive sensor exhibits super-compressibility which can withstand 10,000 cycles under 50% strain, showing a fast response time (6.3 ms) and high sensitivity (177.08 kPa−1). Briefly, this work provides an innovative strategy to obtain nanoarchitecture functional materials integrating multiscale microstructures into carbon-based aerogels, demonstrating their potential to improve the sensing characteristics and functionality of wearable piezoresistive sensors.
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•A tracheid-like carbon aerogel was synthesized by a bidirectional freezing method.•Chitosan served as a “bridge junction” to tightly connect each component.•Finite Element Simulation proved the carbon aerogel with ultra-compressibility.•The carbon aerogel-based sensor was sensitive (177.08 kPa−1) and responsive (6.4 ms).•It also showed excellent signal stability under 50% strain after 10,000 cycles.
•Cornstalk derived hierarchical porous carbons (CHPCs) were synthesized.•LiCl/ZnCl2 as a green and non-toxic template led to tunable pore structure of CHPCs.•The subsequent activation further endowed ...the carbons with enlarged porosity.•High specific capacitance of 375 F g−1 at 0.5 A g-1 in 1 M H2SO4 solution was obtained.•The corresponding symmetric supercapacitor displayed a superior energy density.
An effective and sustainable two-step route including a pre-carbonization and the subsequent pyrolysis/activation to improve pre-carbonization process was developed for synthesizing cornstalk derived hierarchical porous carbons (CHPCs), which showed high porosity (1.498 cm3 g−1 pore volume) and were rich in oxygen groups (15.63 %). The addition of LiCl/ZnCl2 as a green and non-toxic template led to tunable pore structure of carbon materials, which could tailor the pore structure by acting as a pore padding agent and minimizing the collapse of pore channels. Moreover, the subsequent activation further endowed the carbons with enlarged porosity, significantly improving the supercapacitance. The obtained CHPCs exhibited a satisfying specific mass capacity of 375 F g-1 at 0.5 A g−1 in 1 M H2SO4, and the corresponding symmetric supercapacitor set out a superior energy density of 21.6 W h kg−1 while power density is equal to 300 W kg−1, which could make a green light emitting diode (LED) bright for more than 3 min. This salt-template assisted synthesis can effectively enhance the energy storage capacity of HPCs by regulating the pore structure.
Conventional oil-water separation membranes are difficult to establish a trade-off between membrane flux and separation efficiency, and often result in serious secondary contamination due to their ...fouling issue and non-degradability. Herein, a double drying strategy was introduced through a combination of oven-drying and freeze-drying to create a super-wettable and eco-friendly oil-water separating aerogel membrane (TMAdf). Due to the regular nacre-like structures developed in the drying process and the pores formed by freeze-drying, TMAdf aerogel membrane finally develops regularly arranged porous structures. In addition, the aerogel membrane possesses excellent underwater superoleophobicity with a contact angle above 168° and antifouling properties. TMAdf aerogel membrane can effectively separate different kinds of oil-water mixtures and highly emulsified oil-water dispersions under gravity alone, achieving exceptionally high flux (3693 L·m−2·h−1) and efficiency (99 %), while being recyclable. The aerogel membrane also displays stability and universality, making it effective in removing oil droplets from water in corrosive environments such as acids, salts and alkalis. Furthermore, TMAdf aerogel membrane shows long-lasting antibacterial properties (photothermal sterilization up to 6 times) and biodegradability (completely degraded after 50 days in soil). This study presents new ideas and insights for the fabrication of multifunctional membranes for oil-water separation.
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•A double drying strategy was introduced to fabricate the aerogel film (TMAdf).•The TMAdf aerogel film obtained regularly arranged porous structures with great strength.•The aerogel film exhibited superhydrophilicity and underwater superoleophobicity.•The aerogel film separated oily wastewater with exceptional high flux and efficiency.•TMAdf aerogel film showed circulating antibacterial properties and biodegradability.
The development of highly effective chitosan-based hemostatic materials that can be utilized for deep wound hemostasis remains a considerable challenge. In this study, a hemostatic antibacterial ...chitosan/N-hydroxyethyl acrylamide (NHEMAA)/Ti3C2Tx (CSNT) composite cryogel was facilely prepared through the physical interactions between the three components and the spontaneous condensation of NHEMAA. Because of the formation of strong crosslinked network, the CSNT cryogel showed a developed pore structure (~ 99.07 %) and superfast water/blood-triggered shape recovery, enabling it to fill the wound after contacting the blood. Its capillary effect, amino groups, negative charges, and affinity with lipid collectively induced rapid hemostasis, which was confirmed by in vitro and in vivo analysis. In addition, CSNT cryogel showed excellent photothermal antibacterial activities, high biosafety, and in vivo wound healing ability. Furthermore, the presence of chitosan effectively prevented the oxidation of MXene, thus enabling the long-term storage of the MXene-reinforced cryogel. Thus, our hemostatic cryogel demonstrates promising potential for clinical application and commercialization, as it combines high resilience, rapid hemostasis, efficient sterilization, long-term storage, and easy mass production.
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