Synthesis of MXene-based nanocomposite electrode supported by PEDOT:PSS-modified cotton fabric for high-performance wearable supercapacitor.

The rapid development of wearable and portable electronic devices prompts the ever-growing demand for wearable, flexible, and light-weight power sources. In this work, a MXene/GNS/PPy@PEDOT/Cotton nanocomposite electrode with excellent electrochemical performances was fabricated using cotton fabric as a substrate. Poly (3,4-ethylenedioxythiophene): poly (styrenesulfonate) (PEDOT:PSS) was coated on the cotton fabric to obtain a conductive substrate through a controllable dip-drying coating process, while a nanocomposite consisting of MXene, Graphene nanoscroll (GNS), and polypyrrole (PPy) was directly synthesized and deposited on the PEDOT:PSS-modified cotton fabric via a one-step in situ polymerization method. The resultant MXene/GNS/PPy@PEDOT/Cotton electrode delivers excellent electrochemical performances including an ultra-high areal capacitance of 4877.2 mF·cm-2 and stable cycling stability with 90 % capacitance retention after 3000 cycles. Moreover, the flexible symmetrical supercapacitor (FSC) assembled with the MXene/GNS/PPy@PEDOT/Cotton electrodes demonstrates a prominent areal capacitance (2685.28 mF·cm-2 at a current density of 1 mA·cm-2) and a high energy density (322.15 µWh·cm-2 at a power density of 0.46 mW·cm-2). In addition, the application of the FSC for wearable electronic devices was demonstrated.

Preparation of MgAl-EDTA-LDH based electrospun nanofiber membrane and its adsorption properties of copper(II) from wastewater.

Adsorption is recognized as one of the most promising technologies applied to remove heavy metals from contaminated water. However, the adsorption efficiency often decreases because of the aggregation and loss of adsorbents. Herein, a novel adsorbent was synthesized by intercalation ethylenediaminetetraacetic acid (EDTA) into layered double hydroxides (LDH) and subsequent encapsulated into PAN polymer matrix using electrospinning. The synthesized electrospun nanofiber membrane (MgAl-EDTA-LDH@PAN) was found to combine the advantages of LDH@PAN nanofiber membrane (high surface area, easy to separate, free from aggregation and loss) and EDTA (powerful chelating agent). The adsorption performance of the MgAl-EDTA-LDH@PAN was evaluated using Cu(II) as target metals by varying experimental conditions such as pH, contact time, initial adsorbent dosage, and temperature. The maximum adsorption capacity of MgAl-EDTA-LDH@PAN was 120.77mg/g with the initial Cu(II) concentrations ranging from 0.6 to 40mg/L. MgAl-EDTA-LDH@PAN was also used in real industrial contaminated water treatment, and the final effluent was approximate to class-I criteria of the National Wastewater Discharge Standard of China. (GB 8978-1996). In addition, Cu K-edge XAS and XPS analyses were applied for unraveling the adsorptive performance of MgAl-EDTA-LDH@PAN by revealing the molecular-level mechanism of Cu(II) uptake.

Study on preparation and fluorescence characteristic of the (Alqx)/Al2O3 nano colloids.

Alumina 8-hydroxyquinoline complexes (Alqx)/Al2O3 nano colloids have been successfully prepared by focused, pulsed laser ablation at the interface of solid Al2O3 and a flowing liquid containing 8-hydroxyquinoline (Q) and one of two polymers (polystyrene, PS, and polymethyl methacrylate, PMMA). Three factors influenced the luminescence of the (Alqx)/Al2O3 nano colloids. The first factor was whether the 8-hydroxyquinoline was added before or after laser ablation. The second factor was if the reaction medium consisted of (1) Q dissolved in ethanol, (2) Q dissolved in cyclohexane containing PS, or (3) Q dissolved in ethyl acetate containing PMMA. The third factor affecting luminescence was the age of the colloids. The (Alqx)/Al2O3 nano colloid product was characterized by transmission electron microscopy (TEM), ultraviolet visible spectroscopy (UV-vis), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and fluorescence spectroscopy. The product from all three-reaction media luminesced when irradiated with ultraviolet light. The product formed in cyclohexane containing PS gave the greatest luminescence, followed by the product formed in ethanol, and the product formed in ethyl acetate containing PMMA gave the smallest luminescence. The luminescence mechanism is similar to that of Alq3.

[Study on spectral properties of tri-functional polymers containing terbium complex].

In the present paper, a kind of tri-functional polymer containing terbium complex was synthesized. The spectral properties were studied by means of FTIR, UV-Vis, and TOF-SIMS. The results indicated that the polymer contained the oxadiazole group, carbazole group and terbium complex. The fluorescence property was investigated in different states. In solution, the spectra consisted of the emission band from the pi-->pi* transition of the oxadiazole and carbazole group and the emission peaks from the transitions between the 4f states of terbium. In solid state, the emission from the oxadiazole and carbazole group was suddenly suppressed, and the result also indicated that the efficiency of energy transfer in the solid state is much higher than that in solution. The polymer emits pure green light under the UV light in solid state.

[Study on the Eu-containing coordination polymer. I. Structural characterization of Eu (III)-thienyltrifluroacetone-poly (styrene-acrylic acid)].

Three samples (a), (b) and (c) of luminescent Eu-containing copolymer (NaEu(III)-TTA-PSAA) were synthesized through the reaction of copolymer of acrylic acid and styrene (Mw = 3000) with metalorganic complex (NaEu(TTA)4) obtained from Eu and thienyltrifluroacetone. These samples of coordination polymers were characterized by FTIR, UV and XPS, and their composition and structures were determined. The results of electrical conductivity methods and elemental analysis indicated that there were different compositions and structures of these coordination polymers in different pH. The results of elemental analysis also showed that the content of Eu3+ in sample (a), (b) and (c) was 11.89%, 12.55% and 13.41%, respectively.