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In this study, Cu-doped ZnO aerogel nanoparticles with a 4% copper concentration (Cu4ZO) were synthesized using a sol–gel method, followed by supercritical drying and heat treatment. The subsequent fabrication of Cu4ZO ceramics through Spark Plasma Sintering (SPS) was characterized by X-ray diffraction (XRD), field-emission gun scanning electron microscopy (FE-SEM) equipped with EDS, and impedance spectroscopy (IS) across a frequency range of 100 Hz to 1 MHz and temperatures from 270 K to 370 K. The SPS–Cu4ZO sample exhibited a hexagonal wurtzite structure with an average crystallite size of approximately 229 ± 10 nm, showcasing a compact structure with discernible pores. The EDS spectrum indicates the presence of the base elements zinc and oxygen with copper like the dopant element. Remarkably, the material displayed distinct electrical properties, featuring high activation energy values of about 0.269 ± 0.021 eV. Complex impedance spectroscopy revealed the impact of temperature on electrical relaxation phenomena, with the Nyquist plot indicating semicircular arc patterns associated with grain boundaries. As temperature increased, a noticeable reduction in the radius of these arcs occurred, coupled with a shift in their center points toward the axis center, suggesting a non-Debye-type relaxation mechanism. Dielectric analyses revealed a temperature-driven evolution of losses, emphasizing the material's conductivity impact. Non-Debye-type behavior, linked to ion diffusion, sheds light on charge storage dynamics. These insights advance potential applications in electronic devices and energy storage. [ABSTRACT FROM AUTHOR]

In the last decade, nanostructuration is a demanding research topic due to the observation of interesting properties and, in consequence, applications on these nanostructures. This review collects the synthesis and possible applications of ZnO nanowires grown by electrodeposition and electroless methods. Respect to the synthesis of ZnO nanowires, growth mechanism and parameters are analysed depending on the technique used, electrodeposition or electroless. The mechanism growth of the nanowires using templateless and hard-templates is analysed resulting in different architecture of the ZnO nanowires. Moreover, ZnO nanowires and hybrid materials based on ZnO are also considered. Depending on the architecture of ZnO nanowires, the properties and applications are different. This review also studies the properties and applications in which ZnO nanowires can be used and how these applications are different depending on the architecture of the nanostructure. This review gives a complete perspective referent to the synthesis, properties and application of ZnO nanowires grown by electrosynthesis techniques. [ABSTRACT FROM AUTHOR]

Recent trends in addressing the impending water crisis focus on the development of innovative water treatment methods. This work utilizes pollen as a core template to synthesize highly efficient onion-like photocatalysts for pollutant mineralization. The study showcases a novel electrochemical synthesis method that maintains the structural integrity of pollen, resulting in increased surface area and enhanced photocatalytic activity. After 90-min of visible light irradiation, over 99% mineralization is achieved. These hybrid photocatalysts demonstrate exceptional stability and efficacy in degrading pollutants. The used photocatalysts can be recycled into biopellets with an ash content of less than 7% (weight), moisture content of less than 8% (weight), and a calorific value of ≈22.1 ± 0.3 MJ kg -1 . Additionally, the resulting ashes serve as effective peroxymonosulphate activators for pollutant mineralization. This process offers sustainable waste management while minimizing waste production, providing a practical solution for water purification. The efficacy of this approach in pollutant removal is underscored by mineralization rates exceeding 99%., (© 2024 The Author(s). Small published by Wiley‐VCH GmbH.)