Carbon nanotubes (CNTs) are a robust material and proven as a promising candidate for a wide range of electronic, optoelectronic and environmental applications. In this work, two different methods were utilized for the preparation of CNTs exhibiting different aspect ratios via chemical vapor deposition (CVD). The as-prepared CNTs were analyzed using scanning electron microscopy (SEM), transmission electron microscopy (TEM), N₂adsorption isotherms, thermogravimetric analysis and Raman spectroscopy in order to investigate their morphological and structural properties. Free-standing CNTs “buckypaper” membranes were fabricated, characterized and tailored to meet the requirements of two applications, i.e., (1) the removal of humic acid (HA) from water and (2) separation of oil-in-water emulsions. It was revealed that the hydrophobic buckypapers showed high separation performance for Shell oil-in-water emulsions filtration, with up to 98% through the accumulation of oil droplets onto the membrane surface. The absorption capacity of buckypaper membranes for various organic liquids (oil, chloroform and toluene) was evaluated over 10 absorption cycles to investigate their recyclability and robustness. Moreover, surface modification was introduced to the pristine CNTs to increase their surface hydrophilicity and improve the pure water permeability of buckypapers. These modified buckypapers showed high flux for HA solutions and excellent HA rejection efficiency up to 95%via size exclusion and electrostatic repulsion mechanisms.

Nanocomposite films composed of polyacrylonitrile (PAN) doped with nickel cobaltite (NCO) nanoparticles (NPs) with different weight ratios have been prepared and characterized. Field emission scanning electron microscopy (FE-SEM) confirmed that the NCO NPs were successfully incorporated into the PAN matrix. The x-ray diffraction (XRD) studies showed that the PAN degree of crystallinity was lowered by the incorporation of NCO NPs in the polymer matrix. Other various characterization techniques including energy dispersive x-ray (EDX), Fourier transform infrared (FTIR), and thermal analysis were used. In addition, the effect of NCO NPs on the dielectric permittivity and ac-conductivity exhibits that the ac conductivity of PAN is enhanced from 0.06 ×10^{− 4} to 3.19 ×10^{− 4} S m⁻¹ by doping with 10 wt% NCO NPs at room temperature (RT) and 1.0 MHz. Moreover, the optical properties showed that the NCO/PAN nanocomposites revealed lower transmittance and narrowed the optical bandgap (E _g) of the PAN from 3.92 to 3.37 eV. Cyclic voltammetry (CV), and galvanostatic charge–discharge (GCD) tests were performed to investigate the electrochemical behavior of the studied nanocomposites. It was found that PAN loaded with 10 wt% NCO NPS attains an excellent specific capacitance of 1241 F g⁻¹ at a current density of 0.5 A/g. Also, the cycling stability is significantly enhanced, and the capacitance retention rate approaches 93.2% after 5000 cycles, which provides the possibility of using the studied nanocomposite films for supercapacitor applications.

Since the discovery of the reversible intercalation of lithium-ion materials associated with promising electrochemical properties, lithium-containing materials have attracted attention in the research and development of effective cathode materials for lithium-ion batteries. Despite various studies on synthesis, and electrochemical properties of lithium-based materials, fairly little fundamental optical and thermodynamic studies are available in the literature. Here, we report on the structure, optical, magnetic, and thermodynamic properties of Li-excess disordered rocksalt, Li_1.3Nb_0.3Mn_0.4O₂ (LNMO) which was comprehensively studied using powder X-ray diffraction, transient absorption spectroscopy, magnetic susceptibility, and low-temperature heat capacity measurements. Charge carrier dynamics and electron–phonon coupling in LNMO were studied using ultra-fast laser spectroscopy. Magnetic susceptibility and specific heat data are consistent with the onset of long-range antiferromagnetic order at the Néel temperatures of 6.5 (1.5) K. The effective magnetic moment of LNMO is found to be 3.60 ${\mu }_B$. The temperature dependence of the inverse magnetic susceptibility follows the Curie–Weiss law in the high-temperature region and shows negative values of the Weiss temperature 52 K (3), confirming the strong AFM interactions.