Malalkere Veerappa Murugendrappa

The current research presents the synthesis, characterization, and application of a novel gas sensor based on polypyrrole/strontium titanate (PPy/STO) nanocomposites for the selective detection of CO₂. Utilizing chemical oxidative polymerization, PPy and PPy/STO nanocomposites with varying STO (10–50) wt.% were synthesized and characterized. The structural and morphological analysis confirms the formation of spherical structure and well-dispersed PPy nanoparticles with increasing crystallinity and interaction of STO in PPy chain particle compactness as the STO content increases. The integration of perovskite STO within the conducting polymer matrix enhances the electronic structure, porosity, and surface area of the composite, promoting improved gas sensing performance. Electrical impedance spectroscopy reveals that the composites exhibit a frequency-dependent dielectric response and conduction attributed to charge carrier mobility and interfacial polarization effects. PPy/STO 20% exhibits highest conductivity and dielectric constants of 0.03604 Scm⁻¹ and 1.074 × 10⁴, respectively. Real-time CO₂ sensing experiments conducted at 50 °C demonstrate good sensitivity, stability, and rapid response/recovery characteristics, particularly for the PPy/STO 10% and 40% composites. These findings highlight the potential of PPy/STO nanocomposites as flexible, lightweight, and efficient materials for portable CO₂ gas sensors, addressing the growing needs for environmental and health monitoring.

Polypyrrole (PPy)-doped bismuth calcium manganite (BCM) nanocomposites were synthesized by chemical polymerization. The amorphous nature of the polypyrrole and the monoclinic crystal structure of the BCM particles (35–65 nm) were confirmed by various microstructural, X-ray powder, and spectroscopy techniques. The DC conductivity analysis via the correlated barrier-hopping (CBH) model and Mott’s variable-range hopping (MVRH) model showed that the nanocomposites exhibited ionic conduction. Activation energies, evaluated from the Arrhenius plots, showed that PPy/BCM-30 (30 wt.% of BCM) had the minimum value of 0.09 eV, indicating maximum conductivity and normal NTCR behavior, with resistance decreasing with temperature. The CBH model described the conduction process, and the AC conductivity measurements indicated that the conductivity was frequency-independent at lower frequencies but became dispersive and frequency-dependent at higher frequencies, conforming to Jonscher’s power law. The study revealed that the transport of electrical charge in the material followed the correlated barrier-hopping (CBH) model. These results demonstrate how promising PPy/BCM nanocomposites are for energy storage, sensors, and electronic materials.

Pharmaceutical waste is a type of bio-waste inevitably generated by the pharmaceutical industry, often due to regulatory changes, product deterioration, or expiration. However, their collection and valorization can be approached from a sustainable perspective, offering potential energy-efficient solutions. In this work, the expired Eslicarbazepine acetate drug (ESLD) was utilized as a sustainable anticorrosive agent against mild steel in a 3 M HCl wash solution. Experimental tests combined with theoretical Density Functional Theory (DFT) and Monte Carlo (MC) simulations revealed the corrosion inhibition potential of ESLD. The gasometrical results revealed a high inhibition efficiency rate of 98% upon increases in concentration of expired ESLD from 0.25 to 1.00 mg·L⁻¹, whereas hydrogen gas evolution decreased to 0.7 mL. An impedance investigation evidenced the pivotal role of charge transfer in reducing the disintegration process. As per DFT computations and MC simulation, electron-rich elements in the expired ESLD were key in controlling the dissolution through the adsorption process. Contact angle studies revealed that the increment in the contact angle from 61° to 80° in the presence of expired ESLD validates the chemical, electrochemical, and computational results. This approach not only mitigates pharmaceutical pollution, but also exemplifies the integration of green chemistry principles into corrosion protection, contributing to energy-efficient and sustainable industrial practices.

This study aims to investigate the electric, dielectric poperies, and the charge transport mechanism in Polyaniline/Tin disulfide (PANI/SnS₂) nanocomposites. SnS₂ nanoflowers were synthesized using the hydrothermal method and were utilized to synthesize PANI/SnS₂ nanocomposites by in‐situ polymerization of the aniline. PANI/SnS₂ nanocomposites were composed of hexagonal nanoflowers and amorphous PANI. The charge transport mechanism was investigated by using DC and AC conductivities. DC conductivity increased and reached a maximum value at 5 wt. % sample and then it decreased indicating the percolation effect. To understand the charge transfer mechanism in the PANI/SnS₂ composites, AC conductivity, dielectric properties, and impedance characteristics were investigated in the frequency range of 20 Hz to 2 MHz. PANI/SnS₂ nanocomposites follow Jonscher's Power Law of disordered materials with an exponent value ranging from 0.8 to 0.9. The Havriliak – Negami model confirmed that the samples display a non‐Debye relaxation mechanism. The dielectric constant value increases with an increase in the SnS₂ content. These enhanced properties of PANI/SnS₂ nanocomposites suggest that the proposed PANI/SnS₂ nanocomposites are the potential materials for multifunctional applications, especially in nano‐electronic devices.Highlights: Hydrothermal synthesis of SnS₂ Nano flowers. SnS₂/PANI composites were synthesized by the in situ polymerization method. The DC conductivity of 5 wt. % sample shows Percolation threshold. Jonscher's & Havriliak–Negami fittings suggest non‐Debye dielectric relaxation. Charge transfer mechanisms in the composites were studied using Nyquist plots.

Energy demand has become a persistent concern and high‐performance energy storage systems have increasingly undergone development. Supercapacitors and batteries pose great impact on energy storage and garner a great deal of attention from technologies and researchers alike. The performance of energy saving devices is primarily determined by the electrode material in terms of high specific capacitance, excellent conductivity, remarkable natural abundance, and unique electrochemical qualities, also large surface area. Cobalt (Co)‐based materials are unique electrode materials widely used in energy storage devices. Nevertheless, a combination of Co and ferrite materials such as nickel, zinc, and copper, or Co/nonferrite materials like metal–organic frameworks and layered double hydroxides has improved their ultimate efficiency. This review deals with energy storage applications of Co‐based materials, categorizing ferrites, their electrochemical characterization, performance, also design and manufacturing intended to supercapacitors and batteries applications. Summarizing the main outcomes of the literature on batteries and supercapacitors, energy storage systems comprising Co‐based materials combined with carbon nanotubes, graphene, silica, copper, zinc, nickel, cadmium, ferrous, and lanthanum are reviewed and discussed. Lithium‐ion batteries are investigated specifically, and perspectives on Co‐based ferrite development for future generations of supercapacitors and batteries are outlined.

This study examined the structural, morphological, dielectric and AC conductivity properties of CoZnMg ferrite samples (Co0.6Zn0.4-xMgxFe2O4) with x = 0.00, 0.08, 0.16, 0.24, 0.32, 0.40. The sol-gel autocombustion method was used to synthesize the CoZnMg ferrite samples. The produced samples crystallize in the cubic spinel structure, according to an XRD analysis of the structural characteristics. The highly crystalline single-phase cubic spinel structure with a distinct peak in the (311) plane has been confirmed by XRD studies. The diameters of the crystallites have fluctuated between 24.92 and 9.80 nm. SEM, EDX and FTIR used to examine the morphological and elemental characteristics of the samples. According to FE-SEM, adding magnesium to the current ferrite system resulted in the loss of the porous gel structure. According to the relative stoichiometry of the Mg-substituted CoZn ferrite, the EDAX analysis verified the presence of Co, Zn, Mg and O. The investigated samples may be appropriate for a variety of uses, as indicated by the consistent conductivity at low frequencies. Within the frequency range of 100 to 5 MHz, the room temperature, electrical and dielectric properties were examined. The quantity of magnesium dopants and the microstructural features were related to the obtained results. The dielectric characteristics (ε′ and ε″) of the ferrites gradually decreased with frequency, even at higher frequencies. The samples exhibited interfacial polarization, which led to normal dielectric characteristics in line with the Maxwell-Wagner model.