The synthesis of metal oxides using metal-organic framework (MOF) templates allows precise control over surface morphology and tailorable chemical functionality, thereby facilitating the fabrication of highly porous and crystalline structures that are essential for high-performance energy storage devices such as supercapacitors (SCs). This study reports the development of bimetallic oxide ZnMn2O4 materials derived from MOFs through a facile solvothermal synthesis process followed by calcination, aiming to enhance their performance in an asymmetric supercapacitor device. According to the X-ray diffraction (XRD) analysis, the material exhibits a tetragonal crystal structure with the space group I41/amd. Furthermore, Fourier-transform infrared spectroscopy (FTIR) and Raman spectra confirm the presence of metal-oxide bonds within the material. The scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) analyses indicate the presence of a microspherical morphology, while X-ray photoelectron spectroscopy (XPS) confirms that Zn exists in the +2, and Mn in the +3 oxidation state in the ZnMn2O4 material. The electrochemical analysis of the ZnMn2O4 electrode was assessed by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) within a 2 M KOH electrolyte. At a scan rate of 10 mV/s, the ZnMn2O4 electrode exhibited a specific capacitance of 537 F/g, while at a current density of 1 A/g, it provided 558 F/g. The electrode displayed excellent cycle stability, with a capacitance retention of 95.90% and a Coulombic efficiency of 99.95% after 1000 cycles at a current density of 3 A/g. The as-fabricated asymmetric supercapacitor device (ZnMn2O4//activated carbon) showed 69.90% capacitance retention and 72.65% Coulombic efficiency after 5000 cycles at a current density of 3 A/g, while achieving energy and power densities of 50.94 Wh/kg and 800 W/kg, respectively, within a 1.6 V potential window. These findings may contribute to the development of advanced supercapacitors based on bimetallic metal oxide nanostructures derived from MOFs.

This study presents an in-situ approach for synthesizing mesoporous ZnCo2O4 nanosheets derived from metalorganic frameworks (MOFs). These nanosheets are directly grown on a nickel foam (ZnCo2O4/NF) substrate via a simple solvothermal process, followed by the calcination of a Zn/Co MOF@ZIF-67. The substrate serves both as a physical support and as a growth structure, guiding the formation of uniform nanostructures and enabling better control over morphology. The formation of the as-synthesized material was confirmed through powder X-ray diffraction, Fourier-transform infrared spectroscopy, and Raman spectroscopy analyses. The morphology and composition of the material were analyzed using scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The surface area, pore size, and pore volume of the material were characterized by Brunauer-Emmett-Teller analysis. A hierarchical structure and a morphologically tunable MOFs template enhance the electrochemical performance of supercapacitor electrode materials by providing numerous electroactive sites with diverse valence states and short ion-diffusion pathways. The electronic structure and capacitive behavior of the ZnCo2O4/NF system, evaluated using density of states (DOS) and quantum capacitance analyses, exhibits remarkable energy storage efficiency. Experimentally, ZnCo2O4/NF electrode shows a high capacitance of 1338 F/g at a current density of 2 A/g in a 6 M KOH aqueous electrolyte solution over a potential range of 0.0 to 0.65 V. It also retains excellent rate capability at a current density of 5.5 A/g and exhibits good cycling stability, retaining 80.23% capacity over 3000 cycles. Additionally, the assembled symmetric supercapacitor device demonstrates an energy density of 168 Wh/kg at 3300 W/kg, and maintains an energy density of 115 Wh/kg at 9900 W/kg. This device maintains outstanding cycling stability, retaining 75.46% of its capacity after 10,000 cycles at a current density of 3 A/g. The as-synthesized material can improve the design of high-performance supercapacitor electrodes obtained from MOFs-derived metal oxide.

Supercapacitors are gaining prominence as a sustainable energy storage technology since they bridge the gap between batteries and conventional capacitors, offering elevated power density.

The development of a reliable, sensitive, and economical gas sensor is crucial for effective environmental monitoring. In this study, we present the development of an interdigitated electrode (IDE) based graphene nanoplatelet (GnP) and GnP-TiO2 composite NH3 gas sensor operated at room temperature. Firstly, for the synthesis of GnPs, tea extract was used as a green alternative without the use of organic solvents using a kitchen mixer, whereas TiO2 and GnP-TiO2 were prepared via a simple hydrothermal process. An IDE-based chemiresistive sensor of GnPs and GnP-TiO2 was tested for NH3 detection over a wide concentration range of 100 ppb to 100 ppm at room temperature. The GnP-TiO2 composite exhibited a response nearly eight times higher than that of the GnP sensor at 100 ppm NH3. Additionally, the GnP sensor exhibited response and recovery times of 249 and 107 s, respectively, whereas the GnP-TiO2 composite achieved 15 and 30 s, corresponding to an ∼17 fold faster response time and ∼3.5 fold quicker recovery at 100 ppb NH3. Overall, this study advocates the applicability of a grown GnP-TiO2 based composite for NH3 sensing application in ppb level concentration.

Supercapacitors are gaining prominence as a sustainable energy storage technology since they bridge the gap between batteries and conventional capacitors, offering elevated power density. In this work, we present a cost-effective and low-temperature hydrothermal method for the synthesis of CuMnO2 nanostructures. The material exhibits a monoclinic structure with C2/m space group symmetry as confirmed by X-ray diffraction (XRD) analysis. Field emission scanning electron microscopy (FE-SEM) revealed a hexagonal and rod-like structure, while energy dispersive X-ray (EDX) analysis confirmed the presence of Cu, Mn, and O in the material. X-ray photoelectron spectroscopy (XPS) validates the oxidation states of Cu and Mn. CuMnO2 demonstrated a maximum specific capacitance of 451 F g-1 at a current density of 0.3 A g-1 in a three-electrode arrangement with an energy density of 30.7 Wh kg-1. The electrode also maintains good cycling stability, while retaining 70.2% of its initial capacitance after 5000 cycles. The symmetric supercapacitor demonstrates a high specific capacitance of 175 F g-1 at a current density of 0.5 A g-1 with an energy density of 15.5 Wh kg-1 and maintains 71% cyclic stability even after 5000 cycles.

In the past few decades, electronic excitation-induced changes in BiFeO3 (BFO)-type systems have attracted a lot of attention due to their potential for modifying existing material properties and exploring applications. Dense electronic excitation led by Swift Heavy Ion (SHI) irradiation can modify the structural, optical, electrical, and magnetic properties of materials. In the present study, electronic excitation-induced modifications in the structural, microstructural, and resistive switching properties of Pulsed Laser Deposition (PLD)-grown 20% Ca-doped BFO-based heterostructures using a LaNiO3 (LNO) conducting buffer layer on LaAlO3 (LAO) (100) substrates have been studied by varying the ion fluences of 5 & times; 1010, 5 & times; 1011, 1 & times; 1012, and 5 & times; 1012 ions/cm2 of 150 MeV Ag11+ ions. X-ray diffraction confirms the single-phase nature of the heterostructure along with the modulation of the structural strain with ion fluences. Atomic force microscopy (AFM) measurements show changes in grain morphologies, including the formation of hillock-like and track-like defects after ion irradiation. Cross-sectional Scanning Electron Microscopy (SEM) and Rutherford Backscattering spectroscopy (RBS) measurements confirm the interface modifications due to ion irradiation, which play an important role in charge conduction. Interface modification, formation of oxygen vacancies, and structural defects due to SHI irradiation affect the resistive switching and charge conduction in the proposed system, which is also validated by theoretical fittings of the space charge-limited conduction mechanism. In addition, the impact of ion irradiation on the optical band gap has been understood using UV-visible spectroscopy and correlated with other results.

Pyrophosphates have acquired considerable attention as a potential electrode material in energy storage devices due to their strong covalent P-O bonds, which ensure structural stability, high electrochemical activity, and efficient ion migration. In this contribution, we synthesize copper pyrophosphate (Cu₂P₂O₇) by using a simple co-precipitation method followed by calcination at 500°C for 30 minutes. The monoclinic structure of the material with space group C12/c1 was confirmed by powder X-ray diffraction. The Cu₂P₂O₇ bonds were confirmed using Raman spectroscopy, while Fourier transform infrared spectroscopy confirmed the bending vibration of P-O-P and P-O bonds. X-ray Photoelectron Spectroscopy validates the +2-oxidation state of Copper and Phosphorus. The Cu₂P₂O₇ structures are agglomerated in nature, as observed by Field emission scanning electron microscopy, providing an interconnected network to facilitate ion diffusion. The symmetric supercapacitor device of Cu₂P₂O₇ possesses an excellent specific capacity of 225 F/g with a power density and energy density of 3200 W/kg and 80 Wh/kg at a current density of 1 A/g, respectively. The symmetric device retains about 90% of its initial capacity after 10,000 cycles at a current density of 1.5 A/g. A single 3V LED red light illuminated continuously for 1 minute and 27 seconds. The electrochemical findings endorse the viability of Cu₂P₂O₇ as a suitable electrode material for long-term energy storage applications.

Pyrophosphates have acquired considerable attention as a potential electrode material in energy storage devices owing to their strong covalent P-O bonds, which ensure structural stability, high electrochemical activity, and efficient ion migration. In this contribution, we synthesized copper pyrophosphate (Cu2P2O7) by using a simple co-precipitation method followed by calcination at 500 °C for 30 minutes. The monoclinic structure of the material with space group C12/c1 was confirmed by powder X-ray diffraction. The Cu2P2O7 bonds were confirmed using Raman spectroscopy, while Fourier transform infrared spectroscopy confirmed the bending vibration of P-O-P and P-O bonds. X-ray Photoelectron Spectroscopy validates the +2-oxidation state of copper and the +5-oxidation state of phosphorus. Field emission scanning electron microscope revealed that the interconnected porous morphology with a rough surface of the material provides abundant active sites for ion movements and facilitates electrolyte penetration. The symmetric supercapacitor device of Cu2P2O7 possesses an excellent specific capacity of 225 F g-1 with a power density and energy density of 3200 W kg-1 and 80 Wh/kg at a current density of 1 A g-1, respectively. The symmetric device retains about 90% of its initial capacity after 10 000 cycles at a current density of 1.5 A g-1. The symmetric device is capable to illuminate a single 3 V red light emitting diode continuously for 1 minute and 27 seconds. The electrochemical findings endorse the viability of Cu2P2O7 as a suitable electrode material for long-term energy storage applications.

Recently, the increasing water pollution due to organic pollutants such as dyes has become one of the major concerns of society. As water is an essential resource for all forms of life, clean water availability is required to sustain life on Earth. Because of this, the cost-effective, hygienic, and easily accessible way to remove such polluting dyes has become a key research area in the last decade. Many materials have been studied for their degradation efficiency, such as oxides, ferrites, perovskites, brownmillerites, etc. Amongst them, brownmillerites are one of the most effective materials for the photodegradation of these pollutants due to their stable oxygendeficient structure, low bandgap, strong redox potential, and most importantly, their ability to effectively absorb visible light. Therefore, we have studied the effectiveness of the Sr2-xCaxFe2O5 (x = 0, 0.5, 1) brownmillerite for photocatalytic degradation of organic dyes, Methylene Blue and Congo Red under natural solar radiation and artificial light sources. To understand the mechanism behind the degradation process, the effect of Calcium doping on the structure, microstructure, and optical properties was studied using Rietveld refinement, Field Emission Scanning Electron Microscopy, UV-visible spectroscopy, and UV-Visible diffusion reflectance spectroscopy, and the study of reaction kinetics was carried out. The investigation of FESEM images demonstrates that Ca-doping considerably influences the surface morphology of the samples. XPS analysis confirmed the Fe3+ valence state in the samples with x = 0 and 1, whereas the coexistence of Fe3+ and Fe2+ states in the sample with x = 0.5. The reusability of the catalyst is tested for 3 cycles under an artificial light source that reveals the subsequent decrement in degradation efficiency, yet it remains above 90% for both MB and CR dyes. The structural stability test indicates that the parent structure deforms and produces SrCO3 and SrFeO3-delta, reducing photocatalytic performance.

The synthesis of metal oxides using metal–organic framework (MOF) templates allows precise control over surface morphology and tailorable chemical functionality, thereby facilitating the fabrication of highly porous and crystalline structures that are essential for high‐performance energy storage devices such as supercapacitors (SCs). This study reports the development of bimetallic oxide ZnMn 2 O 4 materials derived from MOFs through a facile solvothermal synthesis process followed by calcination, aiming to enhance their performance in an asymmetric supercapacitor device. According to the X‐ray diffraction (XRD) analysis, the material exhibits a tetragonal crystal structure with the space group I4 1 / amd . Furthermore, Fourier‐transform infrared spectroscopy (FTIR) and Raman spectra confirm the presence of metal–oxide bonds within the material. The scanning electron microscopy (SEM) and high‐resolution transmission electron microscopy (HRTEM) analyses indicate the presence of a microspherical morphology, while X‐ray photoelectron spectroscopy (XPS) confirms that Zn exists in the +2, and Mn in the +3 oxidation state in the ZnMn 2 O 4 material. The electrochemical analysis of the ZnMn 2 O 4 electrode was assessed by cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS) within a 2 M KOH electrolyte. At a scan rate of 10 mV/s, the ZnMn 2 O 4 electrode exhibited a specific capacitance of 537 F/g, while at a current density of 1 A/g, it provided 558 F/g. The electrode displayed excellent cycle stability, with a capacitance retention of 95.90% and a Coulombic efficiency of 99.95% after 1000 cycles at a current density of 3 A/g. The as‐fabricated asymmetric supercapacitor device (ZnMn 2 O 4 //activated carbon) showed 69.90% capacitance retention and 72.65% Coulombic efficiency after 5000 cycles at a current density of 3 A/g, while achieving energy and power densities of 50.94 Wh/kg and 800 W/kg, respectively, within a 1.6 V potential window. These findings may contribute to the development of advanced supercapacitors based on bimetallic metal oxide nanostructures derived from MOFs.

Gas sensors play a critical role in ensuring safety, environmental monitoring, and industrial process control. In this study, carbon nanostructures synthesized from onion waste were employed to develop free-standing Carbon/TiO2 thin films through a hydrothermal method, offering an eco-friendly approach for advanced sensing applications. Grown free-standing Carbon/TiO2 composite film exhibits a unique morphology, featuring tube-like carbon structures decorated with broccoli-flower-shaped TiO2 formations, with an average flower diameter of 8 ± 0.2 µm. A chemiresistive sensor fabricated from carbon/TiO2 composite shows a high response of 339

Sodium-doped Zinc Sulfide (Na:ZnS) nano-crystalline films of varied thicknesses were successfully grown on silica substrates via a colloid-based growth technique. Film thickness was controlled by adjusting the number of coats (3-6). The obtained Na:ZnS films exhibited hole-dominated conductivity, demonstrating potential for ambipolar and optronics applications. X-ray diffraction confirmed a multicrystalline cubic sphalerite phase, while SEM imaging revealed randomly oriented spherical grains with increased compactness at higher thicknesses. UV-Vis spectroscopy indicated a redshift in the band gap with increasing thickness, and PL spectra showed 480 nm emission peak attributed to Na-induced defect levels. Electrical measurements revealed resistivity, charge carrier density and mobility in the range of (1.91-7.54) x 102 Omega.cm, (1.02-2.70) x 1015 cm(-3) and (8.2-12.1) cm2/V.s, respectively. Notably, the Na:ZnS-6 film exhibited the lowest resistivity 1.91 x 102 (Omega.cm), the highest conductivity of 5.23 x 10(-3) (Omega(-1).cm(-1)), and mobility of 12.1 (cm2/V.s).

Transition porous metal oxide nanostructures or nanocomposites derived from metal-organic frameworks (MOFs) play a crucial role in supercapacitor (SCs) applications due to their precise control over porous structures, pore volume, and surface area. MOFs derived multimetallic metal oxide can significantly increase SCs performance by improving charge transfer between various metal ions. The present investigation concentrates on the preparation of MOFs derived ZnMn2O4 microspheres by using a simple solvothermal approach followed by calcination. ZnMn2O4 microspheres possess a tetragonal structure with an I41/amd space group confirmed by XRD. The surface area, pore size, and pore volume of the microsphere are 39.083 m2/g, 10.059nm, and 0.098283 cm3/g, respectively. The synergistic effect of zinc (Zn) and manganese (Mn) in MOFs derived ZnMn2O4 microspheres achieved a specific capacitance of 364F/g at a scan rate of 10mV/s within a potential window of -0.2V to 0.9V in a 2M KOH electrolyte solution. Furthermore, MOFs derived ZnMn2O4 electrode exhibited impressive capacitive retention, remaining 90.71% of its initial capacitance after 10,000 charge-discharge cycles at 1A/g current density. A symmetric device was assembled by combining two similar-sized ZnMn2O4 electrodes as an anode and cathode. This symmetric device has a specific capacitance of 487F/g, a high energy density of 162.89Wh/kg, and a power density of 2361.11W/kg at 1A/g current density. This device has long-term cycling stability, retaining 91.45% of its capacity after 10,000 cycles at 3A/g current density. The results suggest that this work will contribute to developing high-capacitance and robust SCs devices to address future energy storage demands.

The pulsed lase deposited layered based thin film heterostructured device have been fabricated in Ag (metal) / Ca doped BiFeO3 (Ferroelectric) / SrTiO3 (Insulator) / ZnO (Semiconductor) MFIS geometry on STO (100) single crystalline substrate. The X-ray diffraction measurement confirm the substrate-oriented growth of Ca doped BiFeO3 and SrTiO3 layer while growth of ZnO is in different geometry due to its different structure than substrate. Surface and microstructural characterization have been carried out using Atomic Force Microscopy measurements which indicates the homogenous grain growth of Ca doped BiFeO3 and ZnO layer. Electrical properties of proposed Ca doped BiFeO3 based MFIS heterostructure have been studied using frequency dependent dielectric, cyclic I-V behaviour (with and without UV illumination) and channel resistance measurements. To understand the electrical property of proposed device, various charge conduction mechanism has understood using the fitting of I-V data. In addition, role of Ca doped BiFeO3 ferroelectric layer in the channel resistance is investigated.

The Rietveld refinement (RR) method in the FullProf suite is used to evaluate the X-ray diffraction (XRD) data and estimate the thermal and structural parameters of the ternary semiconducting compound α-(phase) CdIn 2 Se 4 .

The electrochemical supercapacitor has been shown to be a reliable and innovative type of energy storage technology over the years. Recent research has shown that CoWO4 is a potential material for supercapacitor applications because of its unique characteristics, which make it suitable for energy storage. CoWO4 nanostructures are synthesized using a low-temperature hydrothermal method followed by calcination at 300 degrees C for 2 h. The powder was characterized through XRD with Rietveld refinement, FE-SEM, TEM, Raman spectroscopy, FTIR, XPS, BET and electrochemical techniques. XRD analysis revealed a monoclinic crystal framework of CoWO4 with a space group of P2/c. FE-SEM and TEM results are in good agreement with each other and reveal elongated oval-shaped nanostructures of CoWO4. BET analysis indicates the mesoporosity in the nanostructures, which helps in the increased active sites for an efficient supercapacitor application. XPS results confirm the presence of a Co2+ oxidation state in the CoWO4 nanostructure. The electrochemical characterizations were carried out using a three-electrode system. The CoWO4 electrode indicates a high specific capacitance of 235 F g-1 at 10 mV s-1 in 6 M KOH electrolyte between -0.15 V to 0.45 V potential window and retains 93.25% capacitance even after 10 000 cycles. Additionally, an asymmetric supercapacitor is assembled using the CoWO4 and activated carbon as the positive and negative electrodes, respectively, achieving a maximum energy density of 51.8 W h kg-1 and an excellent capacity retention of 96.43% after 10 000 cycles at 3 A g-1. This work will be helpful in the development of high-capacitive, durable, and safe supercapacitor devices for future energy needs.