Polyamide-imides (PAIs) are highly desired in many applications because of their superior thermal and mechanical properties. In this work, PAI was prepared from an amide-containing diamine and ...dianhydride by polycondensation and thermal treatment. Both PAI films and aligned electrospun nanofibers (ANFs) were fabricated. FT-IR was used to determine the structure formation of PAI at different annealing temperatures. DSC and TGA were used to evaluate the thermal properties of PAI, while tensile test was applied to evaluate the mechanical properties of PAI films and ANFs. The results indicated that the PAI possessed both outstanding thermal stability and mechanical properties, which provide opportunities for applications in gas separation, high temperature filtration, reinforcement, etc.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Superlithiation has been observed in some carbonyl-based organic electrodes, which leads to very high battery capacity. However, as typical carbonyl polymers, polyimides (PIs) exhibited a relatively ...low capacity (≤250 mA h g −1 ) in previous studies because their poor electrical conductivity restricts superlithiation. Therefore, to realize superlithiation, in this study, multilayer graphene (MG) as a conductive additive was incorporated in PI matrix through a blending precipitation and thermal imidization method. As an electrode in lithium-ion batteries, PI–MG exhibited outstanding capacity (612 mA h g −1 at 100 mA g −1 ) and stable long-term cyclability (89.3% capacity retention over 500 cycles at 500 mA g −1 ). Moreover, the battery could be operated stably at various temperatures, and it exhibited very high specific capacity, especially at the high operating temperature of 55 °C (873 mA h g −1 , 0.1C). We believe that this strategy of introducing conductive additives to promote superlithiation is highly applicable to other non-conductive carbonyl polymers for lithium-ion battery applications.
•A novel dual-ratiometric electrochemical sensor was proposed for CBZ detection.•AgNCs serve as both interlayer spacers for MXene and reference electrochemical probe.•The combination of MXene@AgNCs ...and NH2-MWCNTs displays a favorable synergetic effect.•This sensor achieved high sensitivity and selectivity for the detection of CBZ.•The method was successfully employed for CBZ detection in vegetable samples.
In this paper, a novel ratiometric electrochemical sensor for carbendazim (CBZ) detection was constructed by a composite of MXene@Ag nanoclusters and amino-functionalized multi-walled carbon nanotubes (MXene@AgNCs/NH2-MWCNTs). The Ag nanoclusters (AgNCs) embedded in the MXene not only could inhibit the aggregation of MXene flakes and enhance the electrocatalytic ability, but also serve as an internal reference probe for the ratiometric electrochemical detection. Moreover, the introduction of NH2-MWCNTs can further improve the electrochemical signals of CBZ and Ag, resulting in the enhanced signal amplification and higher sensitivity. Based on these characteristics of the MXene@AgNCs/NH2-MWCNTs composite, the proposed sensor exhibits a favorable linear relationship between ICBZ/IAgNCs and the concentration of CBZ ranging from 0.3 nM to 10 μM and a low limit of detection of 0.1 nM. Moreover, the proposed ratiometric electrochemical sensing platform also demonstrates high selectivity, good reproducibility, secular stability, and satisfactory applicability in vegetable samples.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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•Single PI/rGO composite nanofiber by in-situ polymerization and in-situ thermal conversion.•Tensile strength of single nanofiber up to 4.2 GPa (PI/rGO-1.0% single nanofiber).•Modulus ...of single nanofiber up to 121 GPa (PI/rGO-1.2% single nanofiber).•Homogeneous dispersion of rGO by in-situ strategies.•In-situ strategies enhance the interfacial interaction between rGO and PI fibrous matrix.
High mechanical performance electrospun polymeric nanofibers are highly desired for practical applications, especially as reinforcements for composites. However, most of the electrospun polymeric nanofibers present tensile strength < 3 GPa. To overcome such limitation, this work successfully prepared single rGO reinforced polyimide composite nanofiber with tensile strength up to 4.2 GPa (PI/rGO-1.0%) and modulus up to 121 GPa (PI/rGO-1.2%) by applying in-situ polymerization, electrospinning, and in-situ thermal conversion. These mechanical properties are higher than other polymer-based electrospun nanofibers, and 45% and 236% higher than those of neat PI single nanofiber, respectively. The in-situ strategies provide the homogeneous dispersion of rGO in single electrospun nanofibers and enhance the interfacial interaction between rGO and PI. In addition, the PI/rGO composite nanofibers also present excellent thermal stability with glass transition temperature (Tg) > 295 °C, and the 5% thermal decomposition temperature (T5%) > 539 °C. This work would open a new route for the preparation of high performance electrospun nanofibers for composites.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Excessive use of pesticides in modern agriculture results in large amounts of pesticide residues in agricultural production, greatly threatening human health. Herein, novel two-dimensional leaf-like ...zeolitic imidazolate framework-L decorated with multi-walled carbon nanotubes (MWCNTs/ZIF-L) was prepared by a facile solvent way and exploited as electrode material for sensitive electrochemical sensing of thiabendazole (TBZ). Two-dimensional ZIF-L presents high surface area, large pore volume, and abundant active sites, which exhibits high enrichment ability towards TBZ molecules, while the MWCNTs interspersed on ZIF-L can prominently enhance the electron transport capability and improve the electrocatalytic activity for TBZ oxidation. Due to the intriguing synergy between the components, the MWCNTs/ZIF-L-based electrochemical sensor reveals a limit of detection (LOD) of 6.0 nmol·L
−1
, which is lower than that reported in most literatures. Additionally, satisfactory reproducibility and repeatability, long-term stability, and excellent selectivity are acquired. The proposed method was also applied for the detection of TBZ in apple and orange samples with acceptable recoveries.
Graphical abstract
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The polyaniline (PANI)-based pseudo-supercapacitor has been extensively studied due to its good conductivity, ease of synthesis, low-cost monomer, tunable properties and remarkable specific ...capacitance. In this work, a three-dimensional cross-linked carbon network (3D-CCN) was used as a contact-resistance-free substrate for PANI-based pseudo-supercapacitors. The ordered PANI nanowires (PaNWs) were grown on the 3D-CCN to form PaNWs/3D-CCN composites by in-situ polymerization. The PaNWs/3D-CCN composites exhibited a specific capacitance (Cs) of 1191.8 F g−1 at a current density of 0.5 A g−1 and a superior rate capability with 66.4% capacitance retention at 100.0 A g−1. The high specific capacitance is attributed to the thin PaNW coating and the spaced PANI nanowire array, which ensure a higher utilization of PANI due to the ease of diffusion of protons through/on the PANI nanowires. In addition, the unique 3D-CCN was used as a high-conductivity platform (or skeleton) with no contact resistance for fast electron transfer and facile charge transport within the composites. Therefore, the binder-free composites can process rapid gains or losses of electrons and ions, even at a high current density. As a result, the specific capacitance and rate capability of our composites are remarkably higher than those of other PANI composites.
3D cross-linked carbon network wrapped with ordered PANI nanowires was produced as a contact resistance-free electrode for high performance pseudo-supercapacitors, which possess a high power density of more than 37.5 kW kg−1 with an energy density of 61.9 Wh kg−1 at a high applied current of 100.0 A g−1. Display omitted
•3D-cross-linked carbon network (3D-CCN) provides contact resistance-free substrate.•PANI-nanowires (PaNWs) are grown on the 3D-CCN to form PaNWs/3D-CCN composites.•Pseudo-supercapacitor based on PaNWs/3D-CCN composites has a high rate performance.•The contact resistance-free substrate improves the rate capacity of the supercapacitor.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
In this work, carbon nanohorn (CNH)–decorated multi-walled carbon nanotube (MWCNT) (CNH@MWCNT) composite was prepared and used to modify glass carbon electrode (GCE) as sensitive electrochemical ...sensor for niclosamide (NA) determination. Herein, the decoration of CNHs induces higher dispersibility for MWCNTs, and endows the composite with better conductivity, larger surface area, and higher catalytic activity, which leads to significantly enhanced electrochemical behavior toward NA oxidation. The parameters such as mass ratios of CNHs and MWCHTs, the amount of composite materials, the accumulation time, and the solution pH are systematically optimized. Under optimized conditions, the developed electrochemical sensor exhibits a low detection limit of 2.0 nM with a wide linear range of 7.0 nM–10.0 µM and high anti-interference ability. In addition, the sensor displays good stability, repeatability, and reproducibility. The feasibility of the assay was verified by testing NA in brown rice and rice field water samples.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Fibrous cobalt ferrite catalyst was synthesized using the sol–gel method combined with celloulose template. This technology can exactly reproduce the microstructure of cellulose template on nanometer ...level. The obtained cobalt ferrite was characterized by field emission scanning electron microscope (FESEM), x-ray diffractometry (XRD), fourier transform infrared spectroscopy (FT-IR) and vibrating sample magnetometer. Cobalt ferrite exhibited high efficiency to activate peroxymonosulfate (PMS) for the degradation of Acid Orange 7. The effects of experimental parameters including initial pH values of dye solution, effect of concentrations of PMS and CoFe
2
O
4
on Acid Orange 7 degradation were studied. Furthermore, CoFe
2
O
4
also displayed an extremely high catalytic performance in the degradation of Methyl Orange, Reactive Brilliant Red X-3B, Methylene Blue and Rhodamine B. CoFe
2
O
4
retained high degradation efficiency and high stability even after being reused for five runs. The inherent magnetism of ferrite leads to easy separation of catalyst from the reaction mixtures. Consequently, the catalyst durability is improved remarkably.
CoFe
2
O
4
magnetic fiber nanomaterial was synthesized using the sol–gel method combined with celloulose template and exhibited high catalytic activity for AO7 degradation in presence of peroxymonosulfate.
Highlights
CoFe
2
O
4
was prepared by a facile sol–gel combined with celloulose template technique.
CoFe
2
O
4
exhibited high catalytic activity for dye degradation in presence of peroxymonosulfate.
CoFe
2
O
4
showed high stability, good reusability and excellent magnetic properties.
Sulfate radical was verified to be the main reactive species for AO7 degradation.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
In this work, β-cyclodextrin (β-CD)/mesoporous carbon (CMK-8) nanocomposite was synthesized and used as an electrochemical sensing platform for highly sensitive and selective detection of Cu2+. The ...morphology and structure of β-CD/CMK-8 were characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD). In addition, the dates from electrochemical impedance spectroscopy (EIS) and Cyclic voltammetry (CV) demonstrated that the β-CD/CMK-8 possessed a fast electronic transfer rate and large effective surface area. Besides this, the β-CD/CMK-8 composite displayed high enrichment ability toward Cu2+. As a result of these impressive features, the β-CD/CMK-8 modified electrode provided a wide linear response ranging from 0.1 ng·L−1 to 1.0 mg·L−1 with a low detection limit of 0.3 ng·L−1. Furthermore, the repeatability, reproducibility and selectivity of β-CD/CMK-8 towards Cu2+ were commendable. The sensor could be used to detect Cu2+ in real samples. All in all, this work proposes a simple and sensitive method for Cu2+ detection, which provides a reference for the subsequent detection of HMIs.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
A simple and label-free electrochemical aptasensor was developed for ultra-sensitive determination of chloramphenicol (CAP) based on a 2D transition of metal carbides (MXene) loaded with gold ...nanoparticles (AuNPs). The embedded AuNPs not only inhibit the aggregation of MXene sheets, but also improve the quantity of active sites and electronic conductivity. The aptamers (Apts) were able to immobilize on the MXene-AuNP modified electrode surface through Au-S interaction. Upon specifically binding with CAP with high affinity, the CAP-Apt complexes produced low conductivity on the aptasensor surface, leading to a decreased electrochemical signal. The resulting current change was quantitatively correlated with CAP concentration. Under optimized experimental conditions, the constructed aptasensor exhibited a good linear relationship within a wide range of 0.0001-10 nM and with a low detection limit of 0.03 pM for CAP. Moreover, the developed aptasensor has been applied to the determination of CAP concentration in honey samples with satisfactory results.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
