Hybrid nanocomposite (NC) materials comprising organic polymers and inorganic metal nanoparticles (NPs) with unique properties are popular for their advanced technological applications including resistive switching memory devices. Herein, NCs of 2-naphthalene sulphonic acid-doped polyaniline nanotubes (PANI-NSA NTs) and nickel nanoparticles (Ni NPs) were synthesized via a facile chemical synthesis procedure where metallic Ni NPs were embedded in/deposited onto the surface of PANI-NSA NTs by a simple reduction method. Different characterization methods revealed successful deposition of weak ferromagnetic Ni NPs onto the PANI-NSA matrix. The bipolar resistive switching behaviour of the as-synthesized PANI-NSA + Ni NCs was investigated under the application of voltage stress in a two-terminal sandwiched device configuration. The fabricated indium tin oxide/PANI-NSA + Ni/silver (ITO/PANI-NSA + Ni/Ag) device displays bipolar resistive switching properties having a memory window of ∼1.5 × 10³, and switches effectively over 200 cycles. Ohmic conduction in the lower-voltage regime and the space-charge-limited Mott–Gurney current conduction model in the higher-voltage region were identified as major charge conduction mechanisms in the high resistive state of the device. On the other hand, in the entire low resistive state region the experimental data followed the Mott–Gurney conduction model.

This research focuses on valorising waste burnt tires (BTs) through a two-phase oxidation process, leading to the production of onion-like carbon-based nanostructures. The initial carbonization of BTs yielded activated carbon (AC), denoted as “BTSA”, followed by further oxidation using the modified Hummer’s method to produce onion-like carbon designated as “BTHM”. Brunauer–Emmett–Teller (BET) surface area measurements showed 5.49 m²/g, 19.88 m²/g, and 71.08 m²/g for raw BT, BTSA, and BTHM, respectively. Additional surface functionalization oxidations were observed through Fourier-Transform Infrared (FTIR), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM) analyses. Raman spectroscopy indicated an increased graphitic nature during each oxidation stage. BTHM was assessed in batch adsorption studies for cupric wastewater remediation, revealing a two-phase pseudo-first-order behaviour dominated by mass transfer to BTHM. The maximum adsorption capacity for Cu²⁺ on BTHM was determined as 136.1 mg/g at 25 °C. Langmuir adsorption isotherm best described BTHM at a solution pH of 6, while kinetics studies suggested pseudo-second-order kinetics. Furthermore, BTHM, laden with Cu²⁺, served as a catalyst in a model coupling reaction of para-idoanisole and phenol, successfully yielding the desired product. This study highlights the promising potential of BTHM for both environmental remediation and catalytic reuse applications to avoid the generation of secondary environmental waste by the spent adsorbent.