BaTiO3 Nanoparticles Research Articles

A conductive piezoelectric hydrogel combined with perampanel and wireless electrical stimulation for spinal cord injury repair

After experiencing spinal cord injury (SCI), the interruption of electrical signal transmission impedes both nerve regeneration and functional recovery. Despite its potential as a treatment for spinal cord injury, intrathecal electrical stimulation (ES) is hindered by the risk of infection and the need for a subsequent operation to remove the tethered electrical interface, thereby severely limiting its effectiveness and clinical applicability. Herein, we constructed a conductive piezoelectric hydrogel (SFBP/PER) with ultrasound-triggered wireless ES capability and satisfied conductivity for SCI regeneration. The fabrication process involved the integration of perampanel and polypyrrole-modified BaTiO3 nanoparticles into silk fibroin, followed by enzymatic crosslinking at physiological temperature. We demonstrate that the SFBP/PER hydrogel exhibits anti-glutamate excitotoxicity and antioxidative capabilities in vitro. In vivo, experiments revealed that the SFBP/PER hydrogel significantly enhanced recovery of SCI rats by mitigating oxidative stress, apoptosis, and inflammation, reducing lesion cavities, enhancing remyelination, and promoting the regeneration of functional neurons. This study presents a novel approach utilizing a conductive piezoelectric hydrogel system for in vivo ES in tissue engineering applications.

Revealing the three-dimensional arrangement of polar topology in nanoparticles

In the early 2000s, low dimensional ferroelectric systems were predicted to have topologically nontrivial polar structures, such as vortices or skyrmions, depending on mechanical or electrical boundary conditions. A few variants of these structures have been experimentally observed in thin film model systems, where they are engineered by balancing electrostatic charge and elastic distortion energies. However, the measurement and classification of topological textures for general ferroelectric nanostructures have remained elusive, as it requires mapping the local polarization at the atomic scale in three dimensions. Here we unveil topological polar structures in ferroelectric BaTiO3 nanoparticles via atomic electron tomography, which enables us to reconstruct the full three-dimensional arrangement of cation atoms at an individual atom level. Our three-dimensional polarization maps reveal clear topological orderings, along with evidence of size-dependent topological transitions from a single vortex structure to multiple vortices, consistent with theoretical predictions. The discovery of the predicted topological polar ordering in nanoscale ferroelectrics, independent of epitaxial strain, widens the research perspective and offers potential for practical applications utilizing contact-free switchable toroidal moments.

In-situ welding and thermal activation enabled robust nanofibers based triboelectric nanogenerator for sustainable energy harvesting

Nanofiber-based triboelectric nanogenerators (TENGs) show great promise in energy harvesting and sensing applications. However, the poor strength and the instability of the nanofiber structures lead to the constraints on the durability and the lack of stability in the output performance. In this study, BaTiO3@PVDF-HFP nanofibers were prepared by electrospinning, in which BaTiO3 nanoparticles enhanced the charge trapping ability of the nanofibers and provided nucleation sites for β-phase growth. Subsequent solvent and annealing treatment in-situ welded the nanofibers, which greatly improved the mechanical strength and stability of the nanofiber membranes. The annealing process further thermally activated the electroactive β-phase in the PVDF-HFP, which increased the surface charge density of the nanofibers. A flexible TENG based on BaTiO3@PVDF-HFP-p nanofiber was prepared to harvest mechanical energy, which could achieve a maximum output of 482.5 V and 1.9 W m−2, the voltage is more than 1.2–1.5 times higher compared to uncrosslinked nanofibers. The BaTiO3@PVDF-HFP-p-based TENG maintains ultra-stable Voc generation over 7000 cycles compared to the nanofibers without solvent and annealing treated. Finally, its practical application in harvesting ambient mechanical energy was demonstrated, which can harvest wind energy to power LEDs and small electronic devices such as temperature and humidity sensors.

Characterization and Photocatalytic and Antibacterial Properties of Ag- and TiOx-Based (x = 2, 3) Composite Nanomaterials under UV Irradiation.

Metal and metal oxide nanostructured materials have been chemically and physically characterized and tested concerning methylene blue (MB) photoremoval and UV antibacterial activity against Escherichia coli and Staphylococcus aureus. In detail, silver nanoparticles and commercial BaTiO3 nanoparticles were modified to obtain nanocomposites through sonicated sol-gel TiO2 synthesis and the photodeposition of Ag nanoparticles, respectively. The characterization results of pristine nanomaterials and synthetized photocatalysts revealed significant differences in specific surface area (SSA), the presence of impurities in commercial Ag nanoparticles, an anatase phase with brookite traces for TiO2-based nanomaterials, and a mixed cubic-tetragonal phase for BaTiO3. Silver nanoparticles exhibited superior antibacterial activity at different dosages; however, they were inactive in the photoremoval of the dye. The silver-TiOx nanocomposite demonstrated an activity in the UV photodegradation of MB and UV inhibition of bacterial growth. Specifically, TiO2/AgNP (30-50 nm) reduced growth by 487.5 and 1.1 × 103 times for Escherichia coli and Staphylococcus aureus, respectively, at a dose of 500 μg/mL under UV irradiation.

Significantly optimized piezoelectric catalytic properties of surface functionalized Nano-BaTiO3

In piezoelectric catalysis, the interaction between reaction molecules and the catalyst surface is of great significance for designing highly selective reaction processes. In this study, chemically functionalized BaTiO3 nanoparticles were fabricated using the hydrothermal method, and the piezoelectric catalytic activity was evaluated for degradation dye reactants by ultrasonic vibration. Due to surface modification of BaTiO3 nanoparticles, the carboxyl groups will be applied on the surface of BaTiO3 nanoparticles, resulting in the reduction in particle size and an increase in specific surface area. The adsorption of the carboxyl groups on the surface can also improve the ability of the BaTiO3 nanoparticles to capture the organic dyes. A high piezoelectric catalytic reaction rate constant of 0.0716 min−1, together with a degradation efficiency of >90 % was achieved within 30 min under 60 kHz and 100 W ultrasonic conditions. These results show that the surface modification of BaTiO3 nanoparticles brought excellent performance of piezoelectric catalysis by controlling the precursor and hydrothermal parameters. This study provides a new method for the preparation of chemically functionalized piezoelectric catalysts and design of other new highly selective catalysts.

Boosting tribo-catalytic degradation of organic pollutants by BaTiO3 nanoparticles through metallic coatings

Recently, tribo-catalysis has emerged as an appealing technology to harvest mechanical energy for environmental remediation. While most investigations have focused on catalyst optimization to enhance tribo-catalytic degradation, here we studied the effects of some metal disks placed on beaker bottoms (named coatings) on the tribo-catalytic degradation by BaTiO3 (BTO) nanoparticles under magnetic stirring. For 20 mg/L Rhodamine B (RhB) solution, Cr, Cu, and Ti coatings improved the kinetic constants of BTO nanoparticles by 3.1, 3.4, 5.2 folds, respectively. Ti coating was further found to result in 99 % degradation in just 3 h for 50 mg/L RhB solution, and elevate the kinetic constants by 19.1 and 16.6 folds for 20 mg/L methyl orange (MO) and 20 mg/L methylene blue (MB) solutions, respectively. EPR, FL and UV–vis spectroscopy verified that modifying vessel bottom with Ti coating enabled BTO nanoparticles to generate more active species. First-principles calculations of the work functions of Cr, Cu, and Ti surfaces, and the energy-band structure of BTO revealed a decreased electron-hole recombination rate due to the transfer of excited electrons to metallic coatings. These results suggest that modifying vessel bottoms with suitable metallic coatings is a simple, eco-friendly and efficient strategy to boost tribo-catalysis for environmental remediation.

Morphological, and Optical Properties of BaTiO3 Nano Particles

Barium titanate (BaTiO3) nano particles have garnered significant attention due to their unique structural, morphological and optical properties, which hold promise for various technological applications. This study presents a comprehensive investigation in to the synthesis potential of BaTiO3 nano particle. The synthesis of BaTiO3 nano particles was achived through various methods, including sol-gel, hydrothermal, and solvothermal routes, with meticulous control over parameters such as temperature, pH, and precursor concentration to tailor the nano particle size and morphology. The structural characterization using techniques such as x-ray diffraction (XRD) revealed the formation of pure –phase BaTiO3nanoparticles with crystallite sizes in the nanometer range, exhibiting a perovskite strucure. Morphological analysis using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) elucidated the morphology, size distribution, and surface chacteristics of the nano particles. The results showcased well –defined, uniform nano particles with controllable sizes and shapes, ranging from spherical to cubic, depending onthe synthesis conditions. futher more, the optical properties ofBaTiO3 nanoparticles were investigated using UV-visible spectroscopy and photoluminescence spectroscopy. The UV- visible spectra exhibited characteristic absorption peaks corresponding to the electronic transitions within the band structure of BaTio3,while photoluminescence spectra revealed emission peaks indicative of defect states with in the nanoparticle. These optical properties were found to be tunable by varying the nano particle size, morphology, and surface characteristics, offering opportunities for optoelectronic and photonic device applications. The key findings of this study underscore the importance of understanding the interplay between synthesis parameters and resulting structural, morphological, and optical properties of BaTiO3 nanoparticles.

Role of Nd doping on the structural, morphological and optical properties of BaTiO3 nanoparticles hydrothermally synthesized

Herein, we have reported the facile synthesis of pure and neodymium (Nd)-doped BaTiO3 powders via the hydrothermal method. The effects of Nd concentration (2–10 wt %) on the properties of the BaTiO3 powders were studied. Structural and morphological characteristics were realized using X-ray diffraction (XRD), scanning electronic microscopy (SEM), energy dispersive X-ray (EDS), and X-ray photoelectron spectroscopy (XPS). Fourier transform infrared (FT-IR), UV–visible, and photoluminescence (PL) spectroscopies were used for optical analyses. XRD results show that all powders crystallized under a cubic structure with an average crystallite size that was in the range of 35–47 nm. SEM micrographs revealed that the grains were spherical-shaped, with an average size found in the range of 232–390 nm. The EDS analysis detected the presence of Ba, Ti, O, and Nd elements in the elaborate materials. XPS data confirms the introduction of Nd3+ in the BaTiO3 and the amphoteric substitution of Nd3+ in the Ba and Ti sites at 6 and 10 wt%. FT-IR spectra indicate the presence of the Ti–O vibration bonds. UV–visible optical spectra illustrate the enhancement of absorbance with Nd doping. PL spectra exhibit ultraviolet, blue, green, and orange emissions in the samples.

Three‐phase interfacial design in BaTiO3/rGO/polyetherimide composite enabling enhanced dielectric, thermal and mechanical properties

AbstractAs core components in electric/electronic fields, dielectric materials have recently received ever‐increasing interests. Among them, polymer‐based dielectric composites have drawn ever‐increasing attentions due to their high‐temperature resistance and excellent processibility. However, state‐of‐art studies mostly focus on the modification of single‐phase filler, while the heterogeneous three phase interactions between fillers and polymer matrix are rarely studied. To fill this gap, in this study, a novel strategy of interfacial design and structural construction of three‐phase BaTiO3/rGO/polymer nanocomposites have been promoted to simultaneously build interfacial barriers between adjacent rGO nanosheets and to enhance the interfacial polarization of rGO nanosheets for improved dielectric, thermal and mechanical properties. The dielectric constant of 0.6 wt% BT/ARGO/PEI reached 644@1 kHz with a dielectric loss of only 0.218, while these values for 0.5 wt% ARGO/PEI composites are 471 and 0.489, respectively. Meanwhile, the breakdown strength almost doubled (from 48 kV·mm−1 to 87 kV·mm−1) upon the addition of BaTiO3 (BT) nanoparticles. Moreover, the introduced BT nanoparticles significantly enhanced the intermolecular frictions between different materials and contributed largely to promoted mechanical and thermal properties. We therefore speculate this work establishes a strong foundation for fabricating three heterogeneous‐phase high dielectric polymer materials with excellent dielectric, thermal and mechanical properties.Highlights Graphene oxide was modified by APTES and reduced by L‐Ascorbic Acid. Three‐phase BT/ARGO/PEI composites showed enhanced dielectric properties. The incorporated BT nanoparticles reduced the dielectric loss. The thermal and mechanical properties of BT/ARGO/PEI composites are optimized. Interfacial interactions between different phase of materials are studied.

Enhanced piezocatalytic degradation of mixed organic dyes using BaTiO3–MoS2 heterostructure nanocomposites: A mechanistic investigation

Piezocatalysis garners significant interest as a potential solution to environmental issues, specifically regarding dye pollutants. Nonetheless, the main obstacle in the piezoelectric efficiency of materials for eliminating organic pollutants from water has been the recombination of charge carriers. Here we report on the fabrication of a piezoelectric nanocomposite of BaTiO3 (BT) Nanoparticles and MoS2 (MS) Nanosheets for the enhanced piezocatalytic degradation of dye pollutants. The sample with 1.0 wt % MoS2 content (BT/MS1) demonstrates greater efficacy compared to both 2.0 wt % MoS2 (BT/MS2) and BaTiO3 (BT) alone in degrading Rhodamine B (Rh B) and Methyl Orange (MO). Specifically, BT/MS1 exhibits 1.84- and 2.8-times enhanced performance for Rh B and MO degradation respectively, in comparison to BT alone. It is demonstrated that the charge transfer system at the interface of BT and MS effectively lowers the recombination of electron-hole (e‒- h+) pairs, generated during piezocatalysis thereby enhancing the degradation. The composite sample was further used for the successful degradation of a mixture of dyes. This study introduces a novel approach to enhance catalysis by hybrid composite in piezoelectric materials.

Dissolved oxygen enhanced piezo-photocatalytic performance in Ag dots-modified BaTiO3 nanoparticles for efficient degradation of multiple organic pollutants

Piezoelectric nanomaterials have attracted much attention due to their ability to modulate photo-excited carrier separation and migration under strain. Perovskite-structured BaTiO3 (BT) is a promising piezo-photocatalytic material due to its high piezoelectric coefficient and special phase structure. In this work, a series of x wt.% Ag/BT composites prepared by a two-step approach were developed for piezo-photocatalysis applications. The 0.8 wt.% Ag/BT showed an excellent piezo-photocatalytic performance for degrading 75.8 % Rhodamine B (RhB) in 60 min. Especially, the catalytic performances were strongly correlated with the atmosphere conditions of the catalyst. The piezo-photodegradation rate of RhB by 0.8 wt.% Ag/BT under O2 atmosphere reached 95.7 % in 40 min, and the first order kinetic rate constant (k) reached 0.06759 min−1, which was 9.9 and 2.4 times that of N2 and air condition, respectively. The Density functional theory (DFT) calculations further revealed that dissolved oxygen could enhance the material's adsorption of RhB. Compared with hydroxyl free radicals (OH) and holes (h+), superoxide radicals (O2–) play an indispensable role in the catalytic process through the trapping experiments and ESR analyses. Furthermore, the RhB degradation pathway and potential ecotoxicity were also proposed. This work is hoped to provide an understanding the mechanism of piezo-photocatalysis and bring new ideas for the development of piezo-photocatalysis catalysis for multifunctional environmental applications.

Ultrasound-triggerennd piezocatalytic conductive Guar gum/PEDOT: PSS/BTO composite hydrogels for bacterial-infected skin wound healing

Open skin wounds are susceptible to infections by multidrug-resistant bacteria, which can lead to delayed wound healing or worsening of symptoms. Therefore, there is an urgent need to develop a comprehensive strategy that addresses bacterial infections while simultaneously promoting wound healing for optimal clinical outcomes. In this study, we aimed to combine the benefits of antibacterial piezoelectric catalysis action and controlled electrical stimulation to promote skin tissue repair. Initially, piezoelectric catalytic BaTiO3(BTO) nanoparticles were coated with polydopamine (PDA) to improve the interface compatibility between inorganic and organic phase. Subsequently, a novel conductive composite hydrogel termed PPGSCH was synthesized by doping PDA@BTO into poly (3, 4-ethylenedioxythiophene) -poly (styrene sulfonate) (PEDOT: PSS) hydrogel. Traditional dye degradation experiments and EPR tests found that PDA@BTO nanoparticles exhibited superior piezoelectric catalytic efficiency compared with the pristine BTO. Rheological tests and electrical conductivity tests demonstrated better electrical adaptability and mechanical stability of PPGSCH. Remarkably, under the synergism of piezoelectricity and electric polarization induced by ultrasound (US), the antibacterial rate of PPGSCH exceeded 90% in vitro. Furthermore, when subjected to 0.5 W/cm2 US irradiation, it can generate moderate levels of reactive oxygen (ROS) and micro current, promoting the proliferation and migration of mouse fibroblasts. Animal experiments on infected skin wounds in mice showed that PPGSCH could reduce inflammation, accelerate angiogenesis, and ultimately expedite the infected wound healing. This work opens up new possibilities for enhancing the repair of infected skin wounds.

Utilizing a High-Performance Piezoelectric Nanocomposite as a Self-Activating Component in Piezotronic Artificial Mechanoreceptors.

Challenges such as poor dispersion and insufficient polarization of BaTiO3 (BTO) nanoparticles (NPs) within poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) composites have hindered their piezoelectricity, limiting their uses in pressure sensors, nanogenerators, and artificial sensory synapses. Here, we introduce a high-performance piezoelectric nanocomposite material consisting of P(VDF-TrFE)/modified-BTO (mBTO) NPs for use as a self-activating component in a piezotronic artificial mechanoreceptor. To generate high-performance piezoelectric nanocomposite materials, the surface of BTO is hydroxylated, followed by the covalent attachment of (3-aminopropyl)triethoxysilane to improve the dispersibility of mBTO NPs within the P(VDF-TrFE) matrix. We also aim to enhance the crystallization degree of P(VDF-TrFE), the efficiency characteristics of mBTO, and the poling efficiency, even when incorporating small amounts of mBTO NPs. The piezoelectric potential mechanically induced from the P(VDF-TrFE)/mBTO NPs nanocomposite was three times greater than that from P(VDF-TrFE) and twice as high as that from the P(VDF-TrFE)/BTO NPs nanocomposite. The piezoelectric potential generated by mechanical stimuli on the piezoelectric nanocomposite was utilized to activate the synaptic ionogel-gated field-effect transistor for the development of self-powered piezotronics artificial mechanoreceptors on a polyimide substrate. The device successfully emulated fast-adapting (FA) functions found in biological FA mechanoreceptors. This approach has great potential for applications to future intelligent tactile perception technology.

Influence of the surface modification of BaTiO3 nanoparticles by Polyhydroxybutyrate obtained from halophiles bacteria on the optical response intensity of the second harmonic

Influence of the surface modification of BaTiO3 nanoparticles by Polyhydroxybutyrate obtained from halophiles bacteria on the optical response intensity of the second harmonic

Synergistic Stabilization of Zn Metal Anodes by 3D Carbon Frameworks with Multiple Ion Channels Loaded with Zincophilic BaTiO3 Nanoparticles

Aqueous zinc‐ion batteries (AZIBs) suffer from rampant Zn dendrites growth, corrosion and sluggish transport kinetics, all of which have a serious impact on their performance and practical applications. Therefore, porous carbon nanofibers (BTO@PCNFs) loaded with BaTiO3 nanoparticles (BTO NPs) are constructed as a multifunctional interlayer for stabilizing the Zn anodes. Owing to the synergistic effect of BTO NPs and 3D porous carbon framework, this interlayer can achieve uniform electric field distribution, accelerate Zn2+ migration, and promote ion flux homogenization, thus leading to uniform Zn deposition. Meanwhile, the BTO@PCNFs interlayer demonstrates excellent anti‐corrosion effect, which can effectively prevent the side reactions. Benefiting from the synergistic effect of interlayers, the BTO@PCNFs multifunctional interlayers achieve a comprehensive optimization of the Zn anodes. The BTO@PCNFs‐Zn electrode exhibits lower nucleation overpotential (33.5 mV) at 0.5 mA cm−2. The Zn//Zn symmetrical cell with BTO@PCNFs interlayer exhibits ultra‐low overpotential (14 mV) and ultra‐long cycle life (5250 h at 0.5 mA cm−2). Even at high current density (30 mA cm−2), the BTO@PCNFs‐Zn electrode can be stably cycled for more than 830 h, achieving an ultra‐high cumulative capacity of 12 450 mAh cm−2. The multifunctional interlayers can provide a reference for the design of high‐performance Zn anodes.

The Dominance of Pretransitional Effects in Liquid Crystal-Based Nanocolloids: Nematogenic 4-methoxybenzylidene-4'-butylaniline with Transverse Permanent Dipole Moment and BaTiO3 Nanoparticles.

The report presents static, low-frequency, and dynamic dielectric properties in the isotropic liquid, nematic, and solid phases of MBBA and related nanocolloids with paraelectric BaTiO3 nanoparticles (spherical, d = 50 nm). MBBA (4-methoxybenzylidene-4'-butylaniline) is a liquid crystalline compound with a permanent dipole moment transverse to the long molecular axis. The distortions-sensitive analysis of the dielectric constant revealed its hidden pretransitional anomaly, strongly influenced by the addition of nanoparticles. The evolution of the dielectric constant in the nematic phase shows the split into two regions, with the crossover coinciding with the standard melting temperature. The 'universal' exponential-type behavior of the low-frequency contribution to the real part of the dielectric permittivity is found. The critical-like pretransitional behavior in the solid phase is also evidenced. This is explained by linking the Lipovsky model to the Mossotti catastrophe concept under quasi-negative pressure conditions. The explicit preference for the 'critical-like' evolution of the apparent activation enthalpy is worth stressing for dynamics. Finally, the long-range, 'critical-like' behavior of the dissipation factor (D = tgδ), covering the isotropic liquid and nematic phases, is shown.

Enhancing the efficiency of gas sensing on perovskite BaTiO3 nanoparticles using dynamic shock wave flow environment

The effect of nonlinear dynamic shock waves on perovskite BaTiO3 nanoparticles (NPs) is investigated using a table top pressure-driven shock tube (Reddy Tube) for ammonia gas sensing applications with the Mach number of 2.2. In general, shock waves are a nonlinear high-pressure phenomenon characterized by high dynamic pressure and temperature. Raman and powder X-ray diffraction (XRD) methods were utilized to evaluate the molecular and structural characteristics of the BaTiO3 (BTO) NPs under the influence of dynamic shock waves. The surface absorption was assessed using UV- diffuse reflectance spectroscopy (UV-DRS). XRD data shows that BaTiO3 NPs crystallized in tetragonal crystal structure with P4mm space group and stable throughout the shocks, without undergoing any phase change. The average particle size of the control BaTiO3 was 31 nm, while those of shocked BaTiO3 were 62 nm (100 shocks) and 55 nm (200 shocks), demonstrating the significant change in morphology and showing that particles have irregular spherical morphology and are agglomerated by shock wave loaded conditions. Moreover, BaTiO3 nanoparticles were shocked after being tested with various concentrations of different gases at a temperature of 200°C. Under shock loaded conditions, the heightened sensing response for ammonia gases was between 5 and 20 ppm; also, sensing properties such as sensitivity, response, and recovery time indicated that BaTiO3 nanoparticles are a good potential ammonia gas sensing material for real-time sensor applications with enhanced characteristics.

Enhanced piezo-catalytic performance of BaTiO3 nanorods combining highly exposed active crystalline facets and superior deformation capability: Water purification and activation mechanism

Using piezoelectric materials for advanced oxidation is a green and viable means of water purification and environmental restoration. However, unmodified piezoelectric catalysts exhibited unsatisfactory catalytic performance, which had become a bottleneck for the practical application of piezoelectric catalysis. In this work, piezoelectric responsiveness and exposed active crystal surface area were rationally coordinated by synthesizing one-dimensional BaTiO3 nanorods (BTO NRs). Enhanced piezo-responsivity enables faster free charge carriers transfer, while the highly exposed area of the (001) facets provides more active sites for piezo-catalytic reactions. Consequently, BTO NRs degraded RHB (Rhodamine B) and TC (Tetracycline) with first-order rate constants of 0.018 min−1 and 0.012 min−1, respectively, 5 times higher than BaTiO3 nanoparticles. The specific active sites on the (001) crystal plane were further investigated through a combination of DFT calculations, free radical trapping experiments, and XPS analysis. Ti4+ adsorbs and activates water molecules to generate Ti3+ and •OH, in the catalytic reaction. Afterward, Ti3+ is oxidized to Ti4+ by piezo-holes (holes driven by piezoelectric potential), while •OH is desorbed and involved in the degradation of pollutants. This research not only provides an approach to modify piezoelectric catalysts with high catalytic activity but also presents new insights into the mechanism of piezoelectric catalysis from the viewpoint of the atom level.

Investigation of negative permittivity in BaTiO3/TiN metacomposites at the radio frequency region

The intriguing and unexpected properties of metacomposites have attracted significant attention, especially in terms of tuning their negative permittivity. In this study, we fabricated percolative BaTiO3/TiN (BTN) metacomposites employing mesoporous BaTiO3 nanoparticles synthesized via a novel solvothermal method as the matrix, combined with varying concentrations of TiN as the filler. Dielectric properties investigated in the frequency range of 100 Hz to 100 kHz unveiled a transition in the permittivity, shifting from positive to negative as the TiN content increased (primarily noticeable at frequencies above 10 kHz). The initial permittivity shifting is associated with an enhanced interfacial polarization, commonly recognized as Maxwell-Wagner-Sillars effect observed below the percolation threshold. Further, Lorentz model is attributed to induce dielectric resonance in the BaTiO3 matrix triggered by the Ti4+ ions in Ti–O octahedral sites leading to negative permittivity in conjunction with increase in TiN particles above the percolation threshold. Interestingly, AC conductivity exhibited an increase with increasing frequency when TiN content was lower. However, intriguingly, this frequency-dependence in the conductivity of BTN metacomposites did not hold as TiN content increased. Moreover, the investigation of reactance revealed the inductive character derived from the conductive network, a conclusion further confirmed through equivalent circuit analysis. The findings presented in this study are poised to unlock new possibilities in the design and development of metacomposites, ultimately facilitating practical applications of epsilon-negative materials in electromagnetic devices.

Aeration-driven piezoelectric activation of peroxymonosulfate achieves effective mitigation of antibiotic resistance dissemination

The antibiotic resistance dissemination in water has become a globally concerned issue, and the wastewater discharge, especially medical wastewater, is considered as one of the most important sources for antibiotic resistance genes (ARGs). However, the effectiveness of current disinfection techniques in the ARGs reduction still remains controversial. In this study, a novel aeration-driven piezoelectric peroxymonosulfate (PMS) activation system using oxygen-vacancy engineered BaTiO3 (BTO) was developed to effectively eliminate antibiotic resistant bacteria (ARB) and ARGs from water. The ARB can be completely inactivated and ∼3.0 logs of ARGs can be removed by the PMS/BTO/aeration system within 1 h, and the spent BTO nanoparticles can be facilely reused after simple rinsing. The aeration can not only provide the driving force for the piezocatalytic process but also more dissolved oxygen in water that played an important role in the generation of free radicals. The radical quenching experiments and electron spin-resonance (ESR) confirmed that all the free radicals, including singlet oxygen (1O2), hydroxyl radical (OH•), sulfate radical (SO4•−) and superoxide radical (•O2−), contributed to the ARGs reduction and 1O2 radicals were identified as the dominant active species. This work provides a high-efficiency and energy saving approach for the mitigation of ARGs from water as the universal use of aeration in water treatment processes and the good reusability of BTO nanoparticles.