The new phosphate CdZn2Fe4(PO4)6 was prepared by solid-state method and investigated by single-crystal X-ray diffraction. This phase crystallize in typical Howardevansite-type structure within, the triclinic system, space group [[EQUATION]] and unit cell parameters: a = 6.3557(2) Å, b = 8.0376(2) Å, c = 9.3582(3) Å, α = 105.087(1)°, β =107.998(1)° and γ = 101.756(1)°. All atoms of the crystal structure occupy the general positions 2i except Cd(1)2+ cation which on the inversion center 1h(-1). This crystal structure is made up of zigzag chains based on [Fe(1)2O10] and [Fe(2)2O10] dimers intercalated by Zn(1)O5 units. Adjacent chains are interconnected by a regular PO4 tetrahedra and ordered in stacked layers perpendicular to [010]. Such an arrangement gives rise to channels parallel to [100] direction, which host Cd2+ cations. The purity of CdZn2Fe4(PO4)6 in pulverulent form was checked by Powder X-ray diffraction (XRD) and characterized by FT-IR, Raman, UV-vis and EDS spectroscopies. Magnetic measurements reveal a pronounced AFM ordering at TN= 50 K, consistent with the semi empirical Goodenough–Kanamori–Anderson (GKA) rules.

Transforming dielectric polymers into conductive or semiconductive materials opens new avenues for advanced and unprecedented applications. Herein, flexible films were fabricated from TEMPO-oxidized cellulose nanofibers/silver selenide (T-CNF/Ag2Se) nanocomposites. Ag2Se particles were in situ prepared in the presence of TEMPO-oxidized cellulose nanofibers to limit the Ag2Se formation within the nanopores of the TEMPO-oxidized cellulose nanofibers. XRD and FTIR patterns verified the effective embedding of Ag2Se nanoparticles within the T-CNF matrix, where Ag2Se crystallized exclusively in the orthorhombic β-Ag2Se phase. For optoelectronic applications, the optical features were investigated, and Ag2Se has a great impact on transmittance, reflectance, optical band gap, and Urbach energy of CNF. The transmittance was reduced from 10% to 2% in the visible region, while the optical band gap dropped from 4.46 eV for CNF to 2.65 eV for CNF/Ag2Se I. Compared with pure CNF, the CNF/Ag2Se I nanocomposites showed broader M″ peaks that shifted towards higher frequencies, indicating enhanced charge-carrier dynamics due to the additional conductive pathways introduced by the Ag2Se nanoparticles. At 313 K, conductivity followed the order of CNF < CNF/Ag2Se III < CNF/Ag2Se < CNF/Ag2Se II < CNF/Ag2Se I, with the conductivity increased by three orders of magnitude for CNF/Ag2Se I compared with that for the pure CNF. The antimicrobial performance of CNF/Ag2Se at different concentrations was evaluated, and it exhibited high toxicity against E. coli, S. typhimurium, and C. albicans, while S. mutans exhibited more resistance against the nanocomposite materials.

Polycrystalline Ca/Zr co-doped BaTiO3 thin films were deposited on Pt/TiO2/SiO2/Si substrates using chemical solution deposition. The specific composition employed in this work is Ba0.85Ca0.15Zr0.1Ti0.9O3. This study examines the relationship between the number of deposition layers and their effects on the structural, microstructural, dielectric, ferroelectric, and energy storage properties. All the samples exhibited a pure perovskite structure, free from crystalline impurity phases. The optimal film, with six deposition layers (BCZT6), exhibited an orthorhombic structure, characterized by dense and uniform grain growth, as well as a smooth surface. The dielectric properties exhibited high thermal stability and weak frequency dependence, maintaining the temperature coefficient of capacitance (TCC) within +/- 7 % across a wide temperature range from -50 degrees C to 300 degrees C, exceeding the thermal limits of X9R standards (TCC <= +/- 15 % from -55 to 150 degrees C). The thin films exhibited an energy storage density surpassing 12 J/cm(3), with an efficiency of 75 % under a low electric field of 1000 kV/cm. The energy storage performance remained stable from -50 degrees C to 300 degrees C, highlighting the potential of BCZT6 thin film for high-temperature energy storage capacitors. Furthermore, the thin films demonstrated excellent fatigue endurance up to 10(8) charge-discharge cycles and notable piezoelectric behavior, highlighting their multifunctional capabilities.

Hybrid technologies combining wastewater treatment and energy recovery are increasingly important for sustainable development. Microbial fuel cells (MFCs) are attractive bioelectrochemical systems because they use electroactive bacteria to convert organic pollutants into electricity. However, the slow oxygen reduction reaction (ORR) at the cathode remains a major limitation. In this study, four MTiO3 perovskite oxides (M = Mg, Ca, Sr, or Ba) were synthesized by solid-state reaction and evaluated as cathode catalysts in single-chamber MFCs fed with domestic wastewater. Physicochemical and electrochemical analyses showed that the A-site cation, crystallinity, and charge-transfer behavior strongly influenced catalytic activity. Among the tested materials, SrTiO3 achieved the highest power density (76.63 mW m-2), followed by CaTiO3 (67.53 mW m-2), whereas BaTiO3 exhibited the best wastewater treatment performance, with 90% COD removal. MgTiO3 showed the lowest overall activity, mainly due to its lower crystallinity and higher charge-transfer resistance. This work provides a direct comparison of MTiO3 perovskites under identical MFC operating conditions and highlights their potential as low-cost, scalable ORR cathode catalysts for bioelectrochemical wastewater treatment.

Unlocking the potential of ambient mechanical energy for water remediation requires catalysts that transcend the kinetic limitations of conventional materials. This study introduces a novel defect-engineering strategy by embedding Thulium (Tm) into the O-T phase boundary of lead-free KNNBTO3 piezocatalysts. Utilizing Response Surface Methodology (RSM), we optimized the piezocatalytic process, achieving a remarkable 96.24% degradation of Methylene Blue (MB) under ultrasonic excitation (300 W, 45 kHz). The 1 mol% Tm-doped catalyst exhibits a kinetic rate nearly triple that of the pristine host. Mechanistic investigations reveal that Tm incorporation engineers a specific electronic environment characterized by a high density of oxygen vacancies (V-O(center dot center dot)) and emergent Nb4+ shallow donor levels. These defects function synergistically as an electronic funnel, where Nb4+ centers stabilize piezo-generated electrons while V-O(center dot center dot) sites anchor oxygen molecules, drastically lowering the activation energy for the Oxygen Reduction Reaction (ORR). Scavenging experiments confirm the superoxide radical (center dot O-2(-)) as the dominant active species driven by this tailored charge-transfer pathway. This work establishes a robust protocol for manipulating lattice defects to construct high-efficiency, sustainable piezocatalytic systems.

This study analyzes the structural and magnetic properties of a new composite material with a lithium borate glass matrix loaded with electric arc furnace slag, with a composition of 50Li2O-50B2O3-80 wt.% slag. The amorphous nature of the obtained glass is confirmed by X-ray diffraction analysis (XRD). Differential scanning calorimetry (DSC) indicates that the material has an extremely high thermal stability as evidenced by its high glass transition temperature which is due to the reinforcing role of the slag metallic oxides. Additionally, magnetic studies reveal a highly frustrated magnetic state in the disordered system. The significant addition of mixed-valence iron ions (Fe2+/Fe3+) in the slag forms antiferromagnetic interactions in the system. These factors result in the stabilization of the spin-glass-like state. The incorporation of slag within the lithium borate matrix is a promising route to valorize this industrial by-product and to develop new functional materials.

This research outlines an eco-friendly and economical method for synthesizing ZnO-NPS using a solution combustion technique. Zinc nitrate hexahydrate was utilized as the metal precursor, and Aloe-vera leaf latex, known for its biocompatibility, served as a natural combustion fuel without any other chemical additives. The X-RD analysis indicated the formation of a hexagonal wurtzite crystal structure with an average crystallite size of around 18 nm. Additionally, microstructural parameters such as lattice strain, dislocation density, and elastic strain energy density were assessed using Williamson–Hall analysis and the size–strain plot method. The corresponding Energy dispersive X-ray spectroscopy confirms no extra elements appears and successful formation of ZnO-NPS. Transmission electron microscopy (TE-M) revealed that nanoparticles have an almost spherical morphology with an average diameter of about 20.75±3.99 nm. This value closely matches the value obtained from the XR-D analysis. The optical band gap derived from Tauc plots based on UVVIS absorption analysis was found to be approximately 3.28 eV. Photoluminescence emission (PL-E) spectral deconvolution, revealed four emission bands centered at 399.87, 430.47, 544.10, and 586.09 nm. Overall, this study presents a sustainable approach to the synthesis of ZnO-NPS highlighting their prospective applications in biomedical fields and solar energy conversion.

We report a multilayer architecture in which Au nanoparticles embedded in a crystalline anatase TiO2 matrix are incorporated beneath VO2 thin films. This configuration promotes the formation of the monoclinic VO2 (M1) phase and enhances the thermochromic performance of the system. Reflectance and absorbance analyses demonstrate a broadened hysteresis response that extends beyond the conventional NIR domain into the VIS range. Moreover, a clear correlation between optical hysteresis and bandgap evolution was established, providing insight into the interplay between Drude free-carrier contributions and interband transitions during the metal-insulator transition. These findings highlight a promising pathway for tailoring VO2-based thermochromic coatings with dual near-infrared-visible switching capability, offering great potential for energy-efficient smart coatings, wavelength-selective optical devices, and advanced photonic applications.

ABSTRACT Microbial fuel cells (MFCs) provide a sustainable route for simultaneous wastewater treatment and energy recovery. However, their performance is often limited by the sluggish oxygen reduction reaction (ORR) at the cathode. In this study, La 0 . 7 M 0 . 3 MnO 3 (M = Sr, Ca, Ba, and Mg) perovskite oxides were evaluated as cathode catalysts for wastewater‐fed MFCs, with particular attention to the role of magnetic properties in electrocatalytic activity. The materials were characterized by x‐ray diffraction (XRD), scanning electron microscopy (SEM)‐energy‐dispersive x‐ray analysis (EDX), Fourier transform infrared spectroscopy (FT‐IR), and magnetic measurements, while electrochemical performance was assessed through cyclic voltammetry (CV), chronoamperometry (CA), electrochemical impedance spectroscopy (EIS), and polarization analyses. Partial substitution of La 3 + with divalent cations tuned the Mn 3 + /Mn 4 + ratio, crystal structure, magnetic ordering, and electronic conductivity. Among the investigated compositions, La 0 . 7 Sr 0 . 3 MnO 3 (LSMO) showed the strongest ferromagnetic behavior, the lowest charge‐transfer resistance (14.8 Ω), and the highest ORR activity. In single‐chamber MFCs, the LSMO air cathode delivered a maximum power density of 309 mW m − 2 and an open‐circuit voltage (OCV) of 506 mV, clearly outperforming the other catalysts. All materials achieved high COD removal efficiencies (94%–98%). These results demonstrate a strong correlation between magnetic ordering and cathodic electron‐transfer kinetics, highlighting magnetic–electronic structure engineering as a promising strategy for efficient, earth‐abundant MFC cathodes

Hexagonal covellite CuS nanoparticles were prepared using co-precipitation method and examined by experimental characterization together with first-principles calculations. X-RD confirmed the formation of a single CuS phase, while TEM observations showed nanoparticles with crystallite sizes mainly in the range of 13 to 15 nm. The band gap was about 2.36 eV. This value was close to the band gap predicted by PBE, GGA+U calculations, indicating that the selected Hubbard correction gives a reasonable description of characteristics of CuS. The density of states showed that the upper valence band is mainly influenced by Cu- 3d and S- 3p orbital hybridization. The calculated band structure also indicated a direct transition at the Γ point. Optical calculations showed a bulk plasma frequency near 4.8 eV and a strong energy-loss feature around 20.9 eV. The strong near-infrared absorption suggests that CuS nanoparticles may be useful for photothermal conversion and related p-type optoelectronic applications.

Quantum dots (QDs) based on transition metal dichalcogenides such as MoS2 offer an alternative strategy to yield excellent optoelectronic properties and promote their photodetection performances. By synthesizing MoS2 QDs through a controlled electrodeposition process, their superior photodetection properties are unlocked, surpassing those reported in existing literature. Through comprehensive characterization and analysis, the successful fabrication of MoS2 QDs made of a mixture of metallic 1T-MoS2 and semiconductor 1T/2H-MoS2 is demonstrated. The photodetection response of MoS2 QDs samples shows a synergistic effect between the two nuances of MoS2, achieving under a standard solar simulator, 758 A W-1 and 5.210(13) Jones for the responsivity and the detectivity. Surprisingly, under UV excitation at 5 V bias for smaller MoS2 QDs, the device demonstrates impressive responsivity and detectivity reaching up to 1708.7 A W-1 and 1.210(14) Jones, respectively as well as excellent external and internal quantum efficiencies of 5.410(5)% and 7.810(5)% establishing it as one of the highest-performing MoS2-based photodetectors reported so far. This research not only sheds light on the potential of MoS2 QDs but also paves the way for their integration into photodetection technologies with unprecedented sensitivity.

In this present study, glass materials belonging to the CaO-B2O3-V2O5 system with different concentrations of V2O5 were elaborated using the melt-quenching process. The main aim of this paper is to investigate the optical, magnetic and dielectric characteristics of these vitreous materials, and thus determine the impact of vanadium oxide. The optical parameters of the elaborated glassy samples, including the cut-off wavelength, band gap, Urbach energy, refractive index and molar refraction, are investigated in this work. The observed variations in cut-off wavelength, gap energy and refractive index indicated an increase in non-bridging oxygen atoms (NBO) with increasing V2O5 content, which results in the conversion of BO3 to BO4 units. Urbach's energy values indicate that the glass samples with a higher vanadium content exhibit a more stable and uniform glass structure. The introduction of V2O5 increased the refractive index and molar refraction. Furthermore, the magnetic properties revealed the paramagnetic behavior for all the glasses studied. Diamagnetic behavior at higher temperatures was also observed for two glasses, CBV1 and CBV2, as the content of V2O5 decreased. The transition from diamagnetic to the paramagnetic state observed for CBV1 and CBV2 indicates the transformation of V5+ to V4+. The dielectric parameters of glass samples CBV2 and CBV3 increase at higher temperatures, with CBV3 exhibiting a transition between the ferroelectric and the paraelectric phases. Moreover, the study of conductivity reveals the semiconducting nature of the studied glasses. The activation energy decreased with rising vanadium oxide content.

The integration of piezoelectric and catalytic functionalities is rapidly advancing, aiming to improve energy and catalytic efficiency. This study focuses on (1-x)Na0.5Bi0.5TiO3-xAgNbO3 (NBT-xAN) piezoelectric materials, engineered with varying spontaneous polarization directions to act as catalysts. The impact of AgNbO3 substitution on various properties, including microstructure, structural phase, vibrational signatures, optical characteristics, and XPS spectra, was investigated. Increasing substitution levels were found to modify the energy band structure, shifting conduction band (CB) positions to more negative values. This modification enhances photo catalytic degradation rates. Additionally, ultrasonic excitation induces deformation in the piezoelectric material, modulating the internal piezoelectric potential and improving the photocatalytic performance. The synergy between piezocatalysis and photocatalysis facilitates efficient mechanical-to-chemical energy conversions, offering a promising approach to tackle energy and environmental challenges. Response Surface Methodology (RSM) was used to optimize critical process parameters for Methyl Orange (MO) degradation, with time, ultrasonic power, and light power analyzed via a quadratic model in TIBCO Statistica software. Optimal conditions achieved 99.94 % degradation within 30 min, with a kinetic constant of 0.0156 L.mg-1.min-1, three times higher than that of pure NBT. This study underscores the pivotal role of spontaneous polarization in piezo/photobicatalysis, paving the way for high-performance piezo/photobicatalysts.

This study explores the electrocaloric effect (ECE) and the stability of the dielectric permittivity versus temperature in sodium bismuth titanate (NBT) modified with silver niobate (AN). By incorporating Ag+ and Nb5+ ions into the (1-x)Bi0.5Na0.5TiO3 - xAgNbO3 system (x = 0.03, 0.06, 0.09), a morphotropic phase boundary (MPB) is formed between rhombohedral and orthorhombic phases that significantly enhancing the dielectric, ferroelectric, and electrocaloric properties. The results demonstrate a critical transition from negative to positive ECE with the increase of AN concentration. Specifically, the NBTAN0.06 composition exhibits excellent ECE performance, achieving a Delta T of 1.35 K under an applied field, while NBTAN0.09 shows a reduced Delta T of 0.24 K due to a symmetry shift toward a pseudocubic phase. The study emphasizes the role of configurational entropy and dipole order, revealing that low Ag and Nb content disrupts polar regions, leading to higher entropy and altered ECE behavior. Additionally, these materials achieve high permittivity stability (epsilon r = 2550 +/- 10 %) over a broad temperature range (160-500 degrees C), making them ideal for high-temperature P-type ceramic capacitors. This research provides valuable insights into the design of environmentally sustainable materials, paving the way for energy-efficient technologies and advanced electronic applications.

The review highlights the advancements in flexible lead-free piezoelectric materials, emphasizing their potential for energy harvesting and sustainable energy. Although normal piezoelectric materials such as lead zirconate titanate (PZT) have great efficiency, their lead content causes environmental issues. This research focuses on replacement materials like biodegradable polymers and bismuth sodium titanate (BNT), which not only show interesting piezoelectric capabilities but also have advantages in terms of flexibility and biocompatibility. In order to increase piezoelectric performance while maintaining flexibility, it is advised to include inorganic fillers into polymer matrices, therefore qualifying these materials for usage in biomedical and wearable electronics applications. The evaluation also covers the issues resulting from the great usage of these resources, including e-waste and the need of sustainable solutions. The general message of the research underlines the need of developing new piezoelectric materials able to effectively gather mechanical energy from different sources, therefore promoting self-sustaining systems and reducing reliance on traditional power sources. The review also underlines how lead-free piezoelectric materials can boost power density and chemical oxygen demand (COD) removal rates in microbial fuel cells (MFCs), therefore promoting sustainable energy solutions that turn organic waste into bioelectricity.

The present study investigates the effect of manganese incorporation on the structural, dielectric, and waste bioconversion of LiTaO3 ferroelectric material. Conventional solid-state synthesis techniques were utilized to produce powder samples, which were subsequently analyzed using room-temperature X-ray diffraction (XRD) for phase identification. The analysis revealed that the material forms a continuous solid solution within the composition range of 0 to 25 mol% of manganese (Mn), exhibiting R3c-Rombohedral symmetry. Thermal investigations of Raman spectra permitted approaching the ferroelectric–paraelectric phase transition, and dielectric measurements were performed in all investigated samples. The results show that the temperature of ferroelectric-paraelectric phase transition (Tc) decreased with the increasing Mn content. Optical properties of the prepared materials were also measured and tested as photocathodes for microbial fuel cells (MFCs), showing promising performance for x = 0.10, which exceeds values found with other dopants.

The morphotropic phase boundary (MPB) composition in lead free (1-x) Bi0.5Na0.5TiO3-x BaTiO3 (BNTBT) solid solution has attracted extensive research due to its significant potential for piezoelectric and high-power energy storage applications. Here, epitaxial (001) and (111) BNTBT films with composition around the MPB are investigated. A complex domain pattern is evidenced for both film orientation, due to the coexistence of a weak polar phase and a strong polar ferroelectric phase. An electric field induced phase switching is shown in both (001) and (111) oriented film, as well as a weakening of the polar state in the (111) BNTBT film. The enhanced ergodic relaxor state in the (111) BNTBT film gives rise to a reduced piezoelectric response and improved energy storage performances. The epitaxial symmetry engineering is shown to provide a complementary approach to the composition strategy to improve the functional properties in BNTBT films.

In this study, Bi/Co co-doped BaTiO3 perovskites, with excellent visible light absorption properties, were synthesized using the solid-state reaction method. The impact of the co-doping on the structural, optical, and electrical properties, along with the photocatalytic behavior, was investigated. X-ray diffraction and Raman spectroscopy confirm that all compositions exhibit a typical ABO3-type perovskite structure with high crystallinity. Rietveld refinement revealed the existence of a structural transition sequence from P4mm tetragonal to P4/mmm tetragonal, and ultimately to Pm3m cubic, as the BiCoO3 content increases. Analysis of the UV-vis curves revealed an enhancement of the visible light absorption of BaTiO3 and decreased its band gap energy from 3.12 eV to 1.23 eV, with the incorporation of Bi and Co dopants. which allows them to be promising and interesting materials for photocatalysis under visible light. In addition, a reduction of the dielectric permittivity and an increase in dielectric loss, while simultaneously enhancing the electrical conductivity of BaTiO3 were obtained. Furthermore, Impedance analysis indicated that both the grain (G) and grain boundary (GB) significantly contribute to the overall electrical conduction with the semiconductor behavior for all synthesized perovskites. Moreover, the conduction mechanism was elucidated based on the activation energy of the conductivity, revealing that it occurs via the hopping process along ionized oxygen vacancies.

NASICON-type solid electrolytes feature prominently in the improved safety and energy density of solid-state lithium batteries (ASSLBs). Achieving high ionic conductivity in these electrolytes is key to optimizing their performance. In this study, we introduced a new class of NASICON-type materials by doping arsenic into the Li1.3Al0.3Ti1.7(PO4)(3) framework, creating a series of Li1.3+xAl0.3AsxTi1.7-x(PO4)(3) phases with varying arsenic content (x = 0, 0.1, 0.2, 0.3), synthesized using the standard solid-state reaction method. X-ray diffraction confirmed the successful formation of the Li1.3+xAl0.3AsxTi1.7-x(PO4)(3) phases, which was further validated by Rietveld refinement. Structural analyses through FT-IR, Raman spectroscopy, NMR, and ICP-AES studies validate the effective incorporation of arsenic into the lattice. Among the different compositions, Li1.5As0.2Al0.3Ti1.5(PO4)(3) phase stood out due to its high relative density of 89 % and its pore-free microstructure, as observed through scanning electron microscopy results, revealing the largest grain and crystallite size. Notably, doping with arsenic resulted in a significant enhancement in ionic conductivity, increasing from 5.34 x10(-5) Omega(-1) cm(-1) for Li1.3Al0.3Ti1.7(PO4)(3) to 8.57 x10(-4) Omega(-1) cm(-1) for the Li1.5As0.2Al0.3Ti1.5(PO4)(3) at 25 degrees C. With a lithium transference number of 0.99, and a conduction mechanism largely unaffected by changes in temperature or composition, demonstrating its suitability as a promising candidate for solid electrolyte applications.