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Metal-organic framework (MOF) derived metal oxide nanostructures hold immense promise as electrodes for energy storage/conversion applications, notably in supercapacitors and urea oxidation. This study explores into optimizing such nanostructures, specifically focusing on a Zr/Ni ratio of 1:1, which has exhibited favorable electrochemical and catalytic performance. Employing thorough characterization methods, including PXRD analysis, we verified the successful synthesis of a ZrO 2 /NiO binary phase (i.e. Zr/Ni) nanostructure via the MOF-derived approach, showcasing its versatility as a catalyst across diverse energy conversion domains. The Zr/Ni nanostructure electrode displayed noteworthy characteristics, boasting a capacity of 432 C/g alongside exceptional cycling stability of 99%, reflecting battery-like electrochemical behavior. Furthermore, in an asymmetric device setup (Zr/Ni//AC), it achieved a notable potential of up to 1.4 V with an impressive power density of 1044.56 W/kg. Additionally, the Zr/Ni nanostructure demonstrated efficient electrocatalytic activity in urea oxidation, evidenced by a maximum current density of 60 mA/cm2. This underscores its viability as a preferred catalyst in energy conversion applications, signaling opportunities for further exploration and advancement in this dynamic field. [Display omitted] • Successful formation of a binary phase of Zr/Ni nanostructure achieved by single step route. • Zr/Ni nanostructure demonstrated a specific capacity of 432C/g. • Zr/Ni//AC device showed ED of 4.08 Wk/g@ 420 W/kg. • Zr/Ni nanostructure exhibits a low onset voltage (1.34 V) in urea oxidation. • Zr/Ni nanostructure shows the highest current density of 60 mA/cm2. [ABSTRACT FROM AUTHOR]

The contamination of water by organic substances poses a significant global challenge. To address these pressing environmental and energy concerns, this study emphasizes the importance of developing effective photocatalysts powered by sunlight. In this research, we achieved the successful synthesis of a novel photocatalyst comprised of polymeric carbon nitride (CN) nanosheets embedded with Co3O4 material, denoted as CN-CO. The synthesis process involved subjecting the mixture to 500 °C for 10 h in a muffle furnace. Structural and morphological analyses confirmed the formation of CN-CO nanostructures, which exhibited remarkable enhancements in photocatalytic activity for the removal of methylene blue (MB) pollutants under replicated sunlight. After 90 min of exposure, the degradation rate reached an impressive 98.9%, surpassing the degradation rates of 62.3% for pure CN and 89.32% for pure Co3O4 during the same time period. This significant improvement can be attributed to the exceptional light captivation capabilities and efficient charge separation abilities of the CN-CO nanostructures. Furthermore, the CN-CO nanostructures demonstrated impressive photocurrent density-time (j-t) activity under sunlight, with a photocurrent density of 2.51 μA/cm2 at 0.5 V. The CN-CO nanostructure exhibited excellent methanol oxidation reaction (MOR) activity with the highest current density of 83.71 mA/cm2 at an optimal 2 M methanol concentration, benefiting from the synergy effects of CN and CO in the nanostructure. Overall, this study presents a straightforward and effective method for producing CN-based photocatalysts decorated with semiconductor nanosized materials. The outcomes of this research shed light on the design of nanostructures for energy-related applications, while also providing insights into the development of efficient photocatalytic materials for addressing environmental challenges. [ABSTRACT FROM AUTHOR]

Researchers are paying constant attention to preparing ceramic materials faster and cheaper while obtaining optimal physical properties. Their goal is to achieve a smaller grain size that will enable them to enhance the breakdown strength, thus increasing the density and efficiency of energy storage material. In line with this objective, two samples of Sr0.95Bi0.05TiO3 ceramics were selected: one was sintered at 1250 °C for 4 h using a conventional sintering CS process, while the other was sintered at the same temperature for 20 min using a microwave sintering system MWS. Both sintered samples showed a single cubic phase, as confirmed by refinement of the X-ray diffraction data. Morphological results show that the microwave-sintered sample ceramics show better densification exceeding 98%. The morphological results also show that the grain size obtained via microwave sintering is ten times smaller than that obtained with the conventional sintering technique. The P–E loop study shows that the breakdown strength with a microwave sintering system increased 1.5 times compared to the CS technique, resulting in enhanced energy storage density from 0.215 to 0.325 J/cm3. This intriguing technology has energy-saving qualities, quick processing, and homogeneous temperature distribution over the sample. According to our findings, the microwave processing method is one of the most attractive methods that can be used to develop new electronic materials for the next generation of applications. [ABSTRACT FROM AUTHOR]

We report an athermal laser annealing technique to fabricate a high-density array of gold nanoparticles on the surface of hafnium oxide thin films without altering the phase of HfO2. Au (~ 5 nm) films deposited on amorphous HfO2 (~ 10 nm) are subjected to laser annealing by using an Excimer laser (248 nm) to produce Au nanoparticles. It is important to note that the usual thermal methods would change the phase of the HfO2. It is observed that the size of the spherical Au nanoparticles decreases and their surface density increases as the number of laser pulses increases. These Au nanoparticles has induced a significant enhancement in the Raman signature of the standard R6G dye. Further, Metal–Oxide–Semiconductor capacitors were fabricated by depositing another layer of HfO2 followed by metal contacts on the surface of these nanoparticles. The leakage current conduction through the gate oxide with and without embedded nanoparticles has been studied using the Poole–Frenkel and Fowler–Nordheim tunneling mechanisms by examining the leakage current–voltage characteristics. PF tunneling is found to be prominent in these MOS structures with Au nanoparticles, which is attributed to the possible charge trapping by the embedded Au nanoparticles. The capacitance–voltage (C–V) characteristics show a significant broadening in the hysteresis loop indicating the improvement in the storage capacity of these MOS capacitors. [ABSTRACT FROM AUTHOR]

A ferroelectric metal insulator metal (MIM) varactor structure incorporating a floating metal and coplanar waveguide (CPW) has been introduced here. The work of the proposed varactor is based on the field-dependent material properties of (Ba, Sr) TiO3 (BST) thin film. A capacitance tunability of 44% has been achieved for the bias voltage of 0–10 V over a frequency range of 1–3 GHz. The proposed varactor structure yields a compact area, high capacitance density, and reduced mask process (two masks). [ABSTRACT FROM AUTHOR]

This article describes the characterization and analysis of the effects an additional polymer layer has on a high-overtone bulk acoustic wave resonator based on Ba0.5Sr0.5TiO3 (BSTO) thin film by studying its spectral information. From both the simulation (numerical model) and experimental results of the resonator with and without coating, significant difference of both cases is evident in the spacing of the parallel resonance frequencies (SPRFs), effective coupling coefficient (keff2), and quality factor distribution of the resonator. The acoustic velocity of the coated material (SU-8) is calculated from the new periodicity introduced in the SPRF distribution. The SPRF distribution of the SU-8-coated resonator decreases overall as expected due to the additional layer introduced but sharply increases in regions defined by the thickness and acoustic velocity of the SU-8 layer. The mechanical loss of the added layer has significant effect on the parameters of the resonator. The study reveals that this method of characterization can be used to approximate the mechanical loss of materials such as polymers or polymer composites. The simulation with finite-element method agrees with the experimental result. [ABSTRACT FROM AUTHOR]

Barium strontium titanate Ba0.6Sr0.4TiO3 (BST6) thin films are deposited by pulsed laser deposition method at different laser fluences keeping the oxygen pressure constant. X-ray diffraction analysis confirms the formation of single phase cubic BST6 thin films. The strain in the grown films have been investigated, and the results show that the strain is in increased under the application of varying laser fluences. It can be inferred that the laser fluence is an important parameter in tuning the dielectric/ferroelectric properties of the films under optimized conditions. The thin films microstructures have been studied using HRTEM, and the results shows the presence of (110) faceted planes of BST6 with dspacing ~ 2.72-2.79 Å. The optical band gap of the BST6 thin films was calculated by applying the Tauc relation from the transmission spectra in the 190-2500 nm range. The BST6 thin films grown at 2 J cm−2 which shows the best microstructural and optical properties was selected for the microwave dielectric measurements by depositing a test circular patch capacitor. The microwave tunability and dielectric constant (εr) of a well crystallized BST6 thin film were found to be ~ 56 and ~ 284%, respectively at 1 GHz making it suitable for applications in tunable microwave devices. [ABSTRACT FROM AUTHOR]

Zr-substituted Ba0.6Sr0.4TiO3((Ba0.6Sr0.4)(Ti0.8Zr0.2)O3) - BSZT) thin films are deposited by using Pulsed Laser Deposition method with different fluence at optimized conditions on amorphous fused silica substrates. The X-ray diffraction (XRD) pattern of the films confirms the formation of cubic phase. Raman studies are performed to understand vibrational modes present in the films. The optical band gap of deposited BSZT thin films were calculated from the transmittance measurements. Microwave dielectric properties of the thin films deposited at 2 J/cm2were measured. These results show BSZT thin films are useful in tunable microwave devices. [ABSTRACT FROM AUTHOR]

This letter reports the use of the resonant spectrum method to characterize a high overtone bulk acoustic wave resonator (HBAR) which has a thin film ferroelectric BaSrTiO3 (BSTO) active layer on a YAG substrate. The HBAR works on the principle of electric field induced piezoelectricity of the thin film ferroelectric BSTO and exhibits switching functionality. From the parallel and series resonant frequencies of each of the multiple peaks in the frequency spectrum of the HBAR, the distribution of spacing of parallel resonance frequency and the distribution of effective coupling coefficient are studied and parameters like acoustic wave velocity, electromechanical coupling coefficient, elastic constant, and density for the thin film are determined. The influence of dc bias voltages on the distribution of the effective coupling coefficient and the electromechanical coupling coefficient is also reported. This letter also establishes the relationship between the relative tunability of the device capacitance and the electromechanical coupling coefficient. [ABSTRACT FROM AUTHOR]