What happens if you shoot a high-power pulsed laser at a mix of iron and sulfur powders? You obtain iron sulfides NPs (mostly) that can be used for various applications, like, for example, catalysts in water splitting reactions. In this work, targets made of three different ratios of mixed sulfur and iron powders are obtained and used for pulsed laser ablation in ethanol. To ensure uniform powder mixing and distribution, ball milling was used to obtain an additional target of mixed iron and sulfur powder. SEM-EDX, STEM-EELS, and XPS revealed the formation of iron oxide and sulfide compounds, reaching 22.4% of Fe2S3 in the ball-milled sample. In terms of water splitting, the NPs from manually mixed powders resulted in different catalytic activity depending on the iron oxidation and sulfurization, while the ball-milled one resulted in competitive activity both toward hydrogen and oxygen production (334mV overpotential) with a catalyst mass of just 400μg/cm2. This approach report the novel possibility of iron sulfide compounds by mixing iron and sulfur powders and opens the way to synthesize simple compounds NPs just using the non-equilibrium conditions of the laser process. Moreover, if it works with commercial powder, it will also work with recycled powders.
In this work, the Sn-driven ferroelectric-antiferroelectric (FE–AFE) crossover in Ba-modified PLZT ceramics and its influence on structural, dielectric, and polarization responses were investigated. Pb0.87Ba0.10La0.02(Zr0.95–xSnxTi0.05)O3 (PBLZST) ceramics were synthesized via a conventional solid-state reaction route, and a progressive symmetry evolution from rhombohedral (R3c) to tetragonal (P4mm) with increasing Sn content was revealed by X-ray diffraction and Raman spectroscopy, including a phase-coexistence regime and enhanced lattice distortion at intermediate compositions. The polarization behavior was strongly reshaped by this structural crossover, evolving from square ferroelectric loops to slim antiferroelectric-like hysteresis with reduced remanent polarization and coercive field. Notably, highly reversible low-field switching was observed for the PBLZST composition with x = 0.25, achieving ∼90% energy-storage efficiency and a recoverable energy density of 497 mJ/cm3 at 30 kV/cm. These results demonstrate that an effective route for tuning FE–AFE transitions and reversible switching in PLZT-based ceramics can be provided by Sn-induced phase instability and coexistence. The control of ferroelectric-antiferroelectric phase transitions at relatively low electric fields is relevant for the development of efficient dielectric ceramics for energy-storage applications.
Hydrogel patches based on alginate and gelatin were fabricated in four formulations (PS0, PS1, PS0C, PS1C) to elucidate how morphology, thermal stability, optical response, and swelling behaviour jointly determine their suitability as drug-release platforms. A comprehensive multi-technique characterization was performed, integrating atomic force microscopy (AFM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), optical reflectance/transmittance spectroscopy, profilometry, and swelling kinetics. AFM revealed that non-crosslinked samples (PS0, PS1) exhibit smooth but mechanically fragile surfaces, whereas calcium crosslinking (PS0C, PS1C) induces a marked increase in nanoscale heterogeneity and load-bearing microdomains. Thermal analyses (TGA/DSC) confirmed the structural reinforcement of crosslinked networks, showing higher transition temperatures, reduced mass-loss rates, and increased residual mass fractions. Optical measurements demonstrated that crosslinking and dye loading modulate internal scattering and absorption, reflecting changes in microstructural organization. Swelling experiments further highlighted the dominant role of ionic crosslinking in controlling water uptake, with PS0 and PS1 undergoing rapid destabilization, while PS0C and PS1C maintain structural integrity and exhibit slower, diffusion-limited hydration. Taken together, these results show that the combined morphological, thermal, optical, and swelling signatures provide a coherent physical basis for modelling internal diffusivity in Alg/Gel hydrogels. The observed structure–property relationships establish the mechanistic foundation required to predict and optimize drug release from these patches in realistic application scenarios.
In this study, strontium ferrite (SrFe12O19)/polyetheretherketone (PEEK) composites were fabricated by hot-press molding and systematically exposed to acidic (HCl, H2SO4), alkaline (NaOH), and neutral (NaCl solution, salt spray) corrosive media. Multi-scale characterization including scanning electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, and vector network analysis revealed distinct attack pathways: alkaline medium caused severe surface erosion and interfacial degradation of the PEEK matrix; acidic medium induced local surface erosion and microcrack propagation; neutral salt medium mainly introduced physical interfacial perturbations. These microstructural evolutions directly regulated the electromagnetic parameters and critically altered the balance between impedance matching and attenuation constant. Contrary to conventional assumptions, the H2SO4-corroded sample exhibited the best overall absorption performance (RLmin = −37.8 dB, EAB = 3.15 GHz) at a thickness of 10 mm, due to a moderate decrease in permittivity, retention of magnetic loss, and significantly improved impedance matching. In contrast, the NaOH-treated sample showed the worst absorbing performance (RLmin = −38.4 dB but EAB = 0.2 GHz) due to severe impedance mismatch. This study establishes a corrosion-type-dependent "structure–property" linkage, providing a theoretical basis for designing highly stable microwave absorbers for complex service environments.
We present a binary CuO/TiO2 nanocomposite synthesized via a facile hydrothermal method, along with its pristine CuO and TiO2 counterparts, for high-performance supercapacitor applications. The powder X-ray diffraction (PXRD) analysis revealed that the CuO/TiO2 compound has embraced the monoclinic and anatase phase structures. Owing to the combination of nano-flower and nano-spherical architecture, the CuO/TiO2 shows exceptional surface characteristics to provide more reaction centers and shorten the ion transport path. The zeta potentials of the investigated materials ranged from - 4.2 mV (CuO) to - 42 mV (CuO/TiO2), with TiO2 at an intermediate value of - 27 mV, highlighting their diverse surface charge properties. Notably, binary CuO/TiO2's highly negative zeta potential of - 42 mV indicates strong electrostatic repulsion, ensuring excellent colloidal stability and inhibiting aggregation. To determine the optimal electrolyte, data on electrochemical performance were recorded for four electrolytes (KOH, NaOH, Na2SO4 and Na2CO3) at fixed (2 M) concentrations for bare CuO, TiO2 and binary CuO/TiO2 composite in a three-electrode set-up. These findings demonstrate that the CuO/TiO2 nanocomposite exhibits the best capacitive behavior in a variety of electrolytes. In particular, the Na2CO3 aqueous electrolyte exhibits the highest electrochemical capacitance of 417 F g-1 at 1 A g-1 with its long-life span regarding cycling stability of 94 % after 5000 cycles for CuO/TiO2. This is due to the shortest relaxation time, and nearly ideal polarizability. An asymmetric supercapacitor (CuO/TiO2‖AC) assembled in the optimized Na2CO3 electrolyte exhibited a specific capacitance of 104.2 F g-1, an energy density of 9.26 Wh kg-1, a power density of 0.18 kW kg-1, and excellent cycling stability with 93 % capacitance retention after 5000 cycles. Our findings provide a unique perspective on the combination of ionic electrolytes with CuO/TiO2 material and suggest that the charging process can be regulated to yield significant improvements in electrochemical kinetics.
