Synthesis, characterization and dielectric properties evaluation of NiO-Co3O4 nanocomposite

Journal of the Iranian Chemical Society https://doi.org/10.1007/s13738-024-03129-0 ORIGINAL PAPER Synthesis, characterization and dielectric properties evaluation of NiO‑Co3O4 nanocomposite Jalal Amir1 · Sheraz Muhammad2 · Muhammad Kashif2 · Azmat Ali Khan2 · Misbah Gul2 · Hao Sun3 · Muffarih Shah2 · Shohreh Azizi4 · Malik Maaza4,5 Received: 11 June 2024 / Accepted: 27 October 2024 © The Author(s) 2024 Abstract Nanosized materials are increasingly being recognized as inherent components in the development of energy storage devices and other state-of-the-art dielectric applications. In this work, nickel oxide (NiO), cobalt oxide ( Co3O4) and NiO–Co3O4 nanocomposites in different compositions (10%, 20%, 30% and 40%) were successfully synthesized through hydrothermal method, optimizing concentrations of the precursors, and X-ray diffraction confirmed single-phase polycrystalline NiO and Co3O4. SEM images showed that distinct morphologies for each material and FTIR spectra reveal Ni–O and Co–O. UV–visible analysis shows a plasmon peak at 307 nm for NiO and excition absorption at 282 nm for Co3O4. NiO–Co3O4 nanocomposites displayed band gaps ranging from 2.37 eV to 2.67 eV. Dielectric properties showed a decrease in εʹ with frequency, attributed to Maxwell–Wagner and hopping models. AC conductivity increased with frequency due to Co3O4 content and oxygen vacancies. The study suggests potential applications in supercapacitors, spintronics, high-frequency devices and ultra-high dielectric materials. Keywords Nanostructure · Composite · Dielectric properties · Hydrothermal Introduction * Hao Sun * Shohreh Azizi ; 1 Department of Physics, Abdul Wali Khan University Mardan, Mardan 23200, Pakistan 2 Department of Chemistry, Abdul Wali Khan University Mardan, Mardan 23200, Pakistan 3 Faculty of Science, Spainish National Research Council (UAM‑CSIC), Autonomous University of Madrid, 28049 Madrid, Spain 4 UNESCO‑UNISA Africa Chair in Nanosciences/Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, Pretoria P.O. Box 392, South Africa 5 Materials Research Department, Nanosciences Africa Network (NANOADNET), iThemba LABS-National Research Foundation of South Africa, 1 Old Faure Road, Somerset West, Western Cape 1729, Cape Town PO Box722, South Africa Understanding the dielectric properties of materials is pivotal in electronic applications. The dielectric constant serves as a fundamental parameter, delineating a materials ability to store the charge [1]. High dielectric constant materials, for an instant, are indispensable as date dielectric in metal oxide semiconductor (MOS) transistors, memory cells, capacitors and superconductors. Conversely, low dielectric constant value finds utility in electrical insulation and high-speed integrated circuits. The semiconductors industry, buoyed by advancements in dielectric materials, stands as a transformative force in microelectronics [2]. Among these materials, metal oxide dielectrics reign supreme due to their exceptional dielectric and mechanical properties, making them vital components in various thin-film electronic systems [3]. Metal oxide nanoparticles play a ubiquitous role across various fields including sensors, ferrofluids, energy storage, magnetic data storage and catalysis. The dielectric properties of nanoparticles differ significantly from those of their bulk material, depending on factors such as size, shape and boundaries [4]. In recent years, the integration of nanocomposites into various technological fields has garnered Vol.:(0123456789) Journal of the Iranian Chemical Society significant interest due to their unique properties and versatile applications [5, 6]. Particularly in the field of electrical applications, these NPs constructed from nickel oxide and cobalt oxide have shown great promise [7]. Determining the electrical properties of capacitors, especially in complicated systems, requires an understanding of their dielectric behavior. Dielectric permittivity, AC conductivity and electric modulus can be used to study key properties such as polarization, conduction and relaxation; materials with a high dielectric constant are useful for high-K gate dielectrics, memory devices and capacitors. These characteristics are frequently examined using AC impedance spectroscopy to comprehend the internal behavior of the material. The dielectric characteristics of transition metal oxides, especially NiO, are crucial for energy storage devices. Despite being a semiconductor in theory, electron dynamics cause NiO to act like an insulator. Hole diffusion drives conduction in NiO-Co2O3 nanocomposites, where holes are confined to Ni sites. Due to their special qualities, these nanocomposites have found extensive application as dielectric materials in displays such as LCDs and LEDs [8]. Heat treatment is an efficient way to create nickel–cobalt oxide nanoparticles, as evidenced by recent studies. These nanoparticles have customized characteristics and high uniformity, which are important for many applications, such as energy storage systems and electrochemical catalysts [9]. The combination of NiO and Co3O4 offers a synergistic platform for manipulating and enhancing electric properties, owing to the distinctive characteristics of each constituent material [10, 11]. Nickel oxide is known for its semiconducting behavior, electrochemical stability and diverse functionalities making it a cornerstone in various electronic devices [11]. On the other hand, cobalt oxide shows intriguing magnetic properties along with distinctive electrical behavior which renders it valuable in various technological domains [12, 13]. By merging these two transition metal oxides into a nanocomposite structure, we endeavor to exploit the complementary nature of their properties to engineer materials with tailored electrical characteristics. The nanoscale dimensions of the various composite particles introduce additional complexities such as quantum confinement effects which further modulate the material's electrical structure and conductivity. Understanding and elucidating the electric properties of NiO-Co2O3 nanocomposites are imperative for advancing their utilization in a plethora of applications including energy storage systems, sensors, catalysis and electric components [14, 15]. Control of particle size and morphology cannot be achieved by numerous methods such as gas phase growth, sol–gel, pyrolysis, ultrasonic, gamma and microwave irradiation or chemically homogenized precipitation. In contrast, hydrothermal methods stand out for their ability to produce uniformly sized and shaped nanoparticles under controlled conditions. This technique uses high temperatures and pressures, resulting in better crystallization and stronger material properties. In addition, hydrothermal processes use water as the solvent, are environmentally friendly and generally produce fewer impurities, making them ideal for s (...truncated)