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Herein, the performance of asymmetric supercapacitors (ASC) fabricated using ZnCo2O4 (ZCO) nano‐hexagons and orange peel‐derived activated carbon (OPAC) as electrodes was studied. ZCO was prepared by a double hydroxide method and OPAC was prepared from orange peel followed by KOH activation. For ZCO, the calcination temperature was determined using TGA analysis. The XRD showed the presence of a cubic spinel structure. The chemical structure was analyzed using XPS, FTIR, and Raman spectroscopy respectively. For OPAC, the presence of an amorphous nature was inferred; FTIR and Raman studies indicate the presence of functional groups and defect structure in the material. The presence of ZCO nano‐hexagons was observed from SEM and TEM respectively. For OPAC, an interconnected pore structure was observed from the SEM image. The specific capacitance for ZCO and OPAC was found to be 194 F.g−1 and 159 F.g−1 at a current density of 0.25 A.g−1. Further, an ASC was fabricated using ZCO as a positive and OPAC as a negative electrode in 2M KOH‐soaked separator. A cell voltage of 1.2 V was achieved and the specific capacitance was calculated to be 64 F.g−1 at 0.25 A.g−1. Further, the cyclic stability and the changes at the electrode/electrolyte interface were studied. [ABSTRACT FROM AUTHOR]

Enhanced thermal, chemical, and mechanical properties of different metal nanoparticle morphologies integrated with metal oxides have been reported in multiple instances. The chemical and material robustness of metal nanoparticles incorporated surficially and into the bulk of distinct as well as spontaneously formed morphologies of metal oxides through solution-based and microwave-based approaches are investigated in this study. These composites were tested for their chemical and material robustness by exposing films formed on quartz substrates to high temperatures (800 °C) in an air ambient as well as to extreme conditions of pH, often encountered in harsh environment applications such as sensing and catalysis. The changes in the optical properties and crystallinity have been studied using in situ absorption and ex situ X-ray diffraction analyses and electron microscopy. The trends observed with respect to the changes in the plasmonic absorbance were validated theoretically and found to be in reasonable agreement with the experimental data. Confirmations of the phenomena occurring in different morphologies and architectures were thereby corroborated through careful interpretations from experiments and predictions from theoretical models. We, therefore, report a simple solution-based process for achieving engineered harsh environment-compatible nanocomposites through studies specifically tailored for such applications such as catalysis, sensing, energy storage, and enhanced luminescence. [ABSTRACT FROM AUTHOR]

Gallium oxide (Ga2O3) micro-/nanostructures fabricated by facile synthetic methods with attributes such as homogeneity and good dispersity are beneficial for use in oxygen gas sensors and deep UV conducting oxide-based applications. A facile microwave-assisted method using cetyltrimethylammonium bromide (CTAB) as a structure directing surfactant was developed that resulted in morphologies like nanorods, bricks and hexagons by simple tuning of the surfactant concentration, aging and the calcination temperature. Detailed investigations into the evolution of the different morphologies through electron microscopy studies reveal the influence of each of these controlling factors. Room temperature photoluminescence studies and XRD reveal the formation of pristine Ga2O3 wherein XRD was used to further de-convolute the morphological growth. The aid of such characterization tools is important for a comprehensive analysis, which is vital for synthesizing morphologically controlled nano-/micro-materials with good fidelity, an important requirement for their transfer to the application phase. [ABSTRACT FROM AUTHOR]

Noble metal nanoparticles like Au have long been admired for their brilliant colour, significantly influenced by plasmon resonance. When embedded in metal oxides, they exhibit unique properties which make them an excellent choice for sensing in high‐temperature and harsh environment atmospheres. In this review, the various morphologies of Au nanoparticles (AuNPs) used in combination with metal oxides for sensing gases at temperatures greater than 300 °C are discussed. Theoretical discussions on the plasmon resonance properties of AuNPs as well as computational techniques like finite difference time domain (FDTD), are often used for understanding and correlating their extinction spectra and are briefed initially. The sensing properties of AuNPs embedded on a metal oxide matrix (such as TiO2, SiO2, NiO etc) for quantifying multiple analytes are then elucidated. The effect of high temperature as well as gas environments including corrosive atmospheres on such nanocomposites, and the different approaches to comprehend them are presented. Finally, techniques and methods to improve on the challenges associated with the realization and integration such Au‐metal oxide plasmonic nanostructures for applications such as combustion monitoring, fuel cells, and other applications are discussed. [ABSTRACT FROM AUTHOR]

Herein, the performance of asymmetric supercapacitors (ASC) fabricated using ZnCo 2 O 4 (ZCO) nano-hexagons and orange peel-derived activated carbon (OPAC) as electrodes was studied. ZCO was prepared by a double hydroxide method and OPAC was prepared from orange peel followed by KOH activation. For ZCO, the calcination temperature was determined using TGA analysis. The XRD showed the presence of a cubic spinel structure. The chemical structure was analyzed using XPS, FTIR, and Raman spectroscopy respectively. For OPAC, the presence of an amorphous nature was inferred; FTIR and Raman studies indicate the presence of functional groups and defect structure in the material. The presence of ZCO nano-hexagons was observed from SEM and TEM respectively. For OPAC, an interconnected pore structure was observed from the SEM image. The specific capacitance for ZCO and OPAC was found to be 194 F.g -1 and 159 F.g -1 at a current density of 0.25 A.g -1 . Further, an ASC was fabricated using ZCO as a positive and OPAC as a negative electrode in 2M KOH-soaked separator. A cell voltage of 1.2 V was achieved and the specific capacitance was calculated to be 64 F.g -1 at 0.25 A.g -1 . Further, the cyclic stability and the changes at the electrode/electrolyte interface were studied., (© 2024 The Authors. Chemistry - An Asian Journal published by Wiley-VCH GmbH.)