An asymmetric supercapacitor fabricated with CoAl-layered double hydroxide/graphene foam (LDH/GF) composite as the positive electrode and activated carbon derived from expanded graphite (AEG) as negative electrode in aqueous 6 M KOH electrolyte is reported. This CoAl-LDH/GF//AEG cell achieved a specific capacitance of 101.4 F g -1 at a current density of 0.5 A g -1 with a maximum energy density as high as 28 Wh kg -1 and a power density of 1420 W kg -1 . Furthermore, the supercapacitor also exhibited an excellent cycling stability with ∼ 100% capacitance retention after 5000 charging-discharging cycles at a current density of 2 Ag -1 . The results obtained show the potential use of the CoAl-LDH/GF//AEG material as suitable electrode for enhanced energy storage as supercapacitor.

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In this work, a series of nitrogen-doped multi-walled carbon nanotubes (N-MWCNTs) with several weight percentages (0.1, 0.4, 0.8, and 1.0 wt.%) were synthesized by catalytic chemical vapor deposition (CCVD) technique. The N-MWCNTs were first characterized and then dispersed in high-density polyethylene (HDPE) polymer matrix to form a nanocomposite. The HDPE/N-MWCNT nanocomposite films were prepared by melt mixing and hot pressing; a good dispersion in the matrix and a good N-MWCNT-polymer interfacial adhesion have been verified by scanning electron microscopy (SEM). Raman spectroscopy measurements have been performed on prepared samples to confirm the presence and nature of N-MWNTs in HDPE matrix. The X-ray diffraction (XRD) analysis demonstrated that the crystalline structure of HDPE matrix was not affected by the incorporation of the N-MWNTs.

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A membranous shaped Ni/Zn layered double hydroxide based nanohybrid was obtained using a low-cost template-free hydrothermal process at optimized growth conditions of 180 °C for 6 h. The synthesized nanohybrid was structurally, texturally and morphologically characterized using different techniques such as X-ray diffraction, FTIR, XPS spectroscopy, BET analysis and FESEM microscopy. The adsorption performance of our product was estimated through the Azorubine dye removal from synthetic wastewater. We therefore studied the synergic effects of Ni/Zn adsorbent dosage, contact time, pH, adsorbate concentration, stirring speed and temperature on the Azorubine adsorption efficiency. In this investigation, we obtained bi-structure based nanoadsorbent with 54% crystallinity order composed of nickel hydrate and zinc carbonate hydroxides in irregular nanoflake-like mesoporous nanohybrid morphology. Interestingly, it was also revealed to have high specific surface area (SSA) of around 110 m2 g−1 with important textural properties of 18 nm and 0.68 cm3 g−1 average pore size and volume, respectively. Moreover, the adsorption results revealed that this novel Ni/Zn layered double hydroxide (Ni/Zn LDH) was an efficient adsorbent for Az molecule and possesses an adsorptive ability exhibiting a short equilibrium time (60 min) and a high Az adsorption capability (223 mg g−1). This fast removal efficiency was attributed to high contact surface area via mesoporous active sites accompanied with the presence of functional groups (OH− and CO32−). In addition, the Langmuir and Freundlich isotherms were studied, and the results fitted better to the Langmuir isotherm.