Search

The simple oxides like titania, zirconia, and ZnO are famous with their antibacterial (or even antimicrobial) properties as well as their biocompatibility. They are broadly used for air and water filtering, in food packaging, in medicine (for implants, prostheses, and scaffolds), etc. However, these application fields can be broadened by switching to the composite multicomponent compounds (for example, titanates) containing in their unit cell, together with oxygen, several different metallic ions. This review begins with a description of the synthesis methods, starting from wet chemical conversion through the manufacturing of oxide (nano)powders toward mechanosynthesis methods. The morphology of these multicomponent oxides can also be very different (like thin films, complicated multilayers, or porous scaffolds). Further, we discuss in vitro tests. The antimicrobial properties are investigated with Gram-positive or Gram-negative bacteria (like Escherichia coli or Staphylococcus aureus) or fungi. The cytotoxicity can be studied, for example, using mouse mesenchymal stem cells, MSCs (C3H10T1/2), or human osteoblast-like cells (MG63). Other human osteoblast-like cells (SaOS-2) can be used to characterize the cell adhesion, proliferation, and differentiation in vitro. The in vitro tests with individual microbial or cell cultures are rather far away from the real conditions in the human or animal body. Therefore, they have to be followed by in vivo tests, which permit the estimation of the real applicability of novel materials. Further, we discuss the physical, chemical, and biological mechanisms determining the antimicrobial properties and biocompatibility. The possible directions of future developments and novel application areas are described in the concluding section of the review. [ABSTRACT FROM AUTHOR]

Adsorbed water promotes proton conduction in ceramics at ambient conditions prior to its evaporation, apparently leading to the positive temperature coefficient of resistivity (PTCR) effect. Using surface water-containing Cs 2 Ti 6 O 13 (1.8 mol water/mol titanate) as an example, the static conductivity (at 50 °C) of ∼10−5 S cm−1 is one thousand times that at 200 °C due to the enhanced proton conduction. At 50–150 °C, the conductivity decreases by 4 orders of magnitude because water evaporation decreases the number of charge carriers. At 150–400 °C, the conduction in water-free Cs 2 Ti 6 O 13 is thermal-activated with the apparent activation energy E a ∼58–72 kJ mol−1, depending on the formalisms. We show clearly that an endothermic DSC peak (water evaporation) in Cs 2 Ti 6 O 13 coincides with all eight presentations of AC properties examined. Similar correlations are obtained from the TG/DTG curves in Cs 2 Ti 5 O 11 ·H 2 O containing mostly intercalated water. The correlation between thermal analyses and AC properties points out that water molecules essentially contribute to the charge transport at ambient conditions of layered alkali titanates. This scenario might be potentially extended to other humidity-sensitive ceramics. [Display omitted] • Water-induced PTCR effect and Arrhenius-like process are respectively observed in the presence/absence of surface water. • The endothermic water loss peak (DSC) coincides with all representations of AC properties. • Activation energies of conduction from different formalisims were quickly obtained in a single measurement. [ABSTRACT FROM AUTHOR]

The primary goal of this study is to elucidate the structural and electrical characteristics, alongside potential applications, of ceramic-polymeric composites. These composites are achieved by incorporating lithium-lanthanum titanates (Li 3x La 2/3−x TiO 3 - LLTO) into a polyvinyl alcohol polymeric matrix (PVA). The synthesis of lithium-lanthanum titanates occurred through high-energy ball milling method. Then, three types of composites were produced using the solvent casting method: a sample of pure Poly (vinyl alcohol) polymer (PVA), a second PVA composite with the addition of La 0 · 59 Li 0 · 24 TiO 3 (Li-0.24) and a third sample with La0· 56 Li 0 · 33 TiO 3 (Li-0.33). SEM and AFM analyzes revealed notable changes in the morphology and 3D spatial patterns of the films upon incorporating lithium-lanthanum titanates into the PVA matrix. The PVA film presents a topography featuring a more evenly distributed range of topographic heights, indicating a smoother surface structure. With varying LLTO content, the morphology of the PVA composite underwent changes. The lower roughness of the PVA surface is evident from its measured average roughness value (Ra = 1.9 ± 0.5 nm). Upon incorporating LLTO, the surfaces displayed increased roughness, measuring specifically at 40.1 ± 7.3 nm (Li-0.24) and 22.7 ± 5.5 nm (Li-0.33). Notably, there was an approximately 43 % reduction in the average roughness value from Li-0.24 to Li-0.33. The analysis by Raman allowed the identification of functional groups of the PVA polymeric chain, in addition to the presence of some vibrational modes related to the structure of lithium-lanthanum titanates for the sample with the highest content of Li+ ions (Li-0.33). Finally, the sample Li-0.33 showed the lowest value of electrical resistance (67 kΩ) and of phase angle (16°), compared to the PVA (100 MΩ and 90°). These results show that the presence of the LLTO changed the insulating behavior of the PVA matrix changed and improved potential to electronic applications. [ABSTRACT FROM AUTHOR]

This work demonstrates a mechanism of heterogeneous nucleation for the synthesis of BaTiO 3 nanowires utilizing K 2 Ti 4 O 9 as template by manipulating alkalinity, temperature and reaction time. Results suggest that the synthesis of BaTiO 3 does not occur through a hydrothermal ion-exchange, instead, the predominant mechanism observed is the heterogeneous of dissolution-crystallization. The consistency of crystallographic orientation for BaTiO 3 nanowires is affected by the hydrothermal conditions. BaTiO 3 nanowires synthesized at 190 °C/0.2 M exhibit a uniform (100)/(001) crystallographic orientation, albeit not consistently along the length of the nanowires, while BaTiO 3 crystal grains no longer have the same crystallographic orientation at 190 °C/0.8 M. By investigating the reaction mechanism of BaTiO 3 , this work may have great significance for the synthesis of perovskite-type MTiO 3 (M = Ba,Ca, Sr, Pb) utilizing layered titanates. [ABSTRACT FROM AUTHOR]

High-entropy ceramics have garnered significant attention in recent years owing to their exceptional properties and structural diversity. In this work, single-phase medium/high entropy ceramics, namely (Ca 0.2 Sr 0.4 Ba 0.4)(Zr 0.5 Ti 0.5)O 3 and (Ca 0.2 Sr 0.4 Ba 0.4)(Zr 0.1 Ti 0.9)O 3 , were successfully designed and prepared utilizing Spark Plasma Sintering (SPS). A comprehensive investigation was conducted into the phase structure, microscopic morphology, dielectric properties, and thermal behavior of these ceramics. It was observed that all ceramics maintained a cubic perovskite structure (space group: Pm 3 ‾ m), and the introduction of multi-element doping rendered them more stable across a wide frequency and temperature range. Notably, (Ca 0.2 Sr 0.4 Ba 0.4)(Zr 0.5 Ti 0.5)O 3 exhibited remarkably low dielectric loss (0.0001 at 1 kHz) at room temperature, along with excellent dielectric temperature stability (25–400 °C). By reducing the zirconium concentration in (Ca 0.2 Sr 0.4 Ba 0.4)(Zr 0.1 Ti 0.9)O 3 , a slight decrease in dielectric temperature stability was observed (25–350 °C); however, it demonstrated lower thermal conductivity (0.41 W/(m·K), 1200 °C) and maintained good high-temperature stability. The discovery highlights the promising practicality of both ceramics for high-temperature dielectric applications. [ABSTRACT FROM AUTHOR]

Sodium bismuth titanate‐based materials are expected to be an alternative candidate to lead‐based ceramic materials due to their excellent electrical properties. However, the low depolarization temperature (Td) limits their practical application. In this work, the phase structure evolution and microstructure of 0.9(0.4Na1/2Bi1/2TiO3–0.6BiFeO3)–0.1BaTiO3: xZnO (x = 0.01, 0.03, 0.05, and 0.07) (abbreviated as 100xZnO) composite ceramics are investigated, and their piezoelectric properties are improved by combination of constructing 0–3 type composites and quenching treatment technology. The addition of ZnO can increase both Td and d33 because ZnO can enhance the lattice distortion of rhombohedral phase and lead to the increase in ferroelectric order. Specifically, the optimum composition x = 0.03 obtains the d33 value of 106 pC/N (25°C), which retains 84% of the value at room temperature up to 240°C. And the quenching technology further enhances the ferroelectric order and increases Td, which is up to 280°C for x = 0.03. [ABSTRACT FROM AUTHOR]

Advancing the development of high‐temperature piezoelectric sensors requires high‐performance piezoelectric materials with high Curie temperatures, wherein the charge signals can be efficiently collected at elevated temperatures. The bismuth layer‐structured ferroelectric (BLSF) bismuth titanate‐ferrite (Bi5Ti3FeO15, BTF) has recently attracted considerable attention because of its high Curie temperature (TC) of ∼761°C. However, the piezoelectric properties of BTF‐based compounds have not been extensively investigated because of their extremely poor piezoelectric performances and low electrical resistivities at elevated temperatures. Herein, tungsten‐substituted BTF (BTF‐100xW) ceramics were synthesized using a solid‐state reaction method. X‐ray diffraction refinement results confirmed the lattice distortion of the BO6 octahedron, while piezoelectric force microscopy images verified an increase in the domain wall density with tungsten modification, both of which contribute to significant enhancement of the piezoelectric properties of BTF‐100xW as intrinsic and extrinsic contributions, respectively. Remarkably, BTF‐3W exhibits a high TC of 793°C and a large piezoelectric constant (d33) of 24.3 pC/N, which is over three times that of BTF (7.1 pC/N). Importantly, the substitution of tungsten decreases the concentration of oxygen vacancies, increases the direct current electrical resistivity, and improves the electrical homogeneity at high temperatures, resulting in extremely stable piezoelectric and electromechanical properties at high temperatures, with a high in‐situ relative d33 of >90% at 400°C and a small variation in the electromechanical coupling factor (kp) of <8% at temperatures up to 450°C. These results suggest that the tungsten‐substituted BTF is a potential candidate for high‐temperature piezoelectric ceramics, and is a promising material for applications in high‐temperature piezoelectric sensors. [ABSTRACT FROM AUTHOR]

[Display omitted] The conversion-type anode material of iron phosphide (FeP) promises enormous prospects for Na-ion battery technology due to its high theoretical capacity and cost-effectiveness. However, the poor reaction kinetics and large volume expansion of FeP significantly degrade the sodium storage, which remains a daunting challenge. Herein, we demonstrate a binder-free nanotube array architecture constructed by FeP@C hybrid on carbon cloth as advanced anodes to achieve fast and stable sodium storage. The nanotubular structure functions in multiple roles of providing short electron/ion transport distances, smooth electrolyte diffusion channels, and abundant active sites. The carbon layer could not only pave high-speed pathways for electron conductance but also cushion the volume change of FeP. Benefiting from these structural virtues, the FeP@C anode receives a high reversible capacity of 881.7 mAh/g at 0.1 A/g, along with a high initial Coulombic efficiency of 90% and excellent rate capability and cyclability in half and full cells. Moreover, the sodium energy reaction kinetics and mechanism of FeP@C are systematically studied. The present work offers a rational design and construction of high-capacity anode materials for high-energy–density Na-ion batteries. [ABSTRACT FROM AUTHOR]

The present study focuses on the synthesis and characterization of rare-earth titanates, specifically Re 2 TiO 5 (Re La, Nd, Sm), with a particular emphasis on their microwave dielectric properties. The factors influencing the synthesis of La 2 TiO 5 compound through the traditional solid-state method were thoroughly investigated, with a significant finding being the notable impact of moisture absorption in La 2 O 3. The impact of variations in rare-earth cation radii on the structure and dielectric properties was systematically analyzed. Re 2 TiO 5 (Re La, Nd, Sm) ceramics crystallized into an orthorhombic structure with space group Pnam, which was confirmed through Rietveld refinement. The resulting materials demonstrated exceptional microwave dielectric properties characterized by a low permittivity range of 13.72–17.39, high-quality factors ranging from 8331 to 17,795 GHz, and a significantly reduced temperature coefficient of resonance frequency (−33.2∼-12.6 ppm/°C). The correlation between microwave dielectric properties and structural characteristics (including ionic polarizability, packing fraction, and bond valence) was investigated. The exceptional potential of these rare-earth titanates lies in their ability to meet the stringent requirements for low signal transmission delay in wireless communication systems, owing to their advantageous low permittivity within the microwave frequency spectrum. [ABSTRACT FROM AUTHOR]

In this study, 2D/2D ZnIn 2 S 4 /Bi 4 Ti 3 O 12 nanoplate heterojunctions were synthesized to alter the Bi 4 Ti 3 O 12 morphology, modulate the bandgap of Bi 4 Ti 3 O 12 , and enhance the utilization of light. The hydrogen production rate of ZnIn 2 S 4 /Bi 4 Ti 3 O 12 nanoplate with the optimal ratio reaches 27.50 mmol/h g−1. [Display omitted] Improving the separation efficiency of photogenerated carriers plays an important role in photocatalysis. In this study, two-dimensional (2D)/2D zinc indium sulfide (ZnIn 2 S 4)/bismuth titanate (Bi 4 Ti 3 O 12) nanoplate heterojunctions were synthesized to alter the Bi 4 Ti 3 O 12 morphology, modulate the bandgap of Bi 4 Ti 3 O 12 , and enhance the utilization of light. Meanwhile, the construction of the S-scheme heterojunction establishes an internal electric field at the ZnIn 2 S 4 /Bi 4 Ti 3 O 12 heterojunctions interface and achieves the spatial separation of photogenerated charges. The hydrogen production rate of ZnIn 2 S 4 /Bi 4 Ti 3 O 12 nanoplate with the optimal ratio reaches 27.50 mmol h−1 g−1, which is 1.5 times higher than that of ZnIn 2 S 4 /Bi 4 Ti 3 O 12 nanoflower (18.28 mmol h−1 g−1) and 2.4 times higher than that of ZnIn 2 S 4 (11.69 mmol h−1 g−1). The apparent quantum efficiency of ZnIn 2 S 4 /Bi 4 Ti 3 O 12 nanoplate reached 57.9 % under a single wavelength of light at 370 nm. This work provides insights into the study of new materials for photocatalytic hydrogen production. [ABSTRACT FROM AUTHOR]

Iron-enriched ferroelectrics are of particular interest as piezoactive components of piezoelectric-ferrite ME ceramics. This is due to the phase composition similarity and the reduction of expected interfacial doping effects during high-temperature calcination. This idea seems attractive, but laborious due to the significantly limited number of possible piezoelectric–ferrite combinations. Therefore, there is practically no data on such systems in the literature. ME composite ceramics based on the highly efficient Fe-containing Pb(Fe 0.5 Nb 0.5) 0.935 Ti 0.065 O 3 (PFNPT) ferroelectric has been studied. (100-х) wt.% Pb(Fe 0.5 Nb 0.5) 0.935 Ti 0.065 O 3 (PFNPT) + х wt.% Ni 0.9 Co 0.1 Cu 0.1 Fe 1.9 O 4-d (NCCF) composite systems has been obtained by the solid-state method at 1050 °C, with no foreign phases. The specimens densities amounted to ∼80% of the theoretical. It has been shown that the ME conversion efficiency and other composites properties are significantly influenced by the PFNPT precursor pre-treatment method. The maximum value of the ME coefficient ΔΕ/ΔΗ = 75 mV/(cm Oe) has been observed for specimens with x = 50–60 made from PFNPT powder with the addition of Li 2 CO 3. An increase in the ME composites sintering temperature to 1150 °C leads to the formation of Pb 2 Nb 2 O 7 foreign phase with a pyrochlore structure along the grain boundaries. The ME coefficient ΔΕ/ΔΗ does not exceed 15 mV/(cm⋅Oe). There is an threefold decrease in the composites piezoelectric parameters (piezoelectric coefficients d ij , g ij), as well as in their magnetic properties (magnetizations M S , M R) due to piezophase degradation, which is presumably associated with a change in the cations distribution over A and B sublattices of the spinel structure. [ABSTRACT FROM AUTHOR]

In this study, TiO2/P, K-containing grapefruit peel biochar (TiO2/P, K-PC) composites were synthesized in situ biomimetically using grapefruit peel as the bio-template and carbon source and tetrabutyl titanate as the titanium source. This was achieved using the two-step rotary impregnation–calcination method. Adjusting the calcination temperature of the sample in an air atmosphere could regulate the mass ratio of TiO2 to carbon. The prepared samples were subjected to an analysis of their compositions, structures, morphologies, and properties. It demonstrated that the prepared samples were complexes of anatase TiO2 and P, K-containing carbon, with the presence of graphitic carbon. They possessed a unique morphological structure with abundant pores and a large surface area. The grapefruit peel powder played a crucial role in the induction and assembly of TiO2/P, K-PC composites. The sample PCT-400-550 had the best photocatalytic activity, with the degradation rate of RhB, MO, and MB dye solutions reaching more than 99% within 30 min, with satisfactory cyclic stability. The outstanding photocatalytic activity can be credited to its unique morphology and the efficient collaboration between TiO2 and P, K-containing biochar. [ABSTRACT FROM AUTHOR]

Halide perovskite Cs3Bi2Br9 (CBB) has excellent potential in photocatalysis due to its promising light-harvesting properties. However, its photocatalytic performance might be limited due to the unfavorable charge carrier migration and water-induced properties, which limit the stability and photocatalytic performance. Therefore, we address this constraint in this work by synthesizing a stable halide perovskite heterojunction by introducing hydrogen titanate nanosheets (H2Ti3O7-NS, HTiO-NS). Optimizing the weight % (wt%) of CBB enables synthesizing the optimal CBB/HTiO-NS, CBHTNS heterostructure. The detailed morphology and structure characterization proved that the cubic shape of CBB is anchored on the HTiO-NS surface. The 30 wt% CBB/HTiO-NS-30 (CBHTNS-30) heterojunction showed the highest BnOH photooxidation performance with 98% conversion and 75% benzoic acid (BzA) selectivity at 2 h under blue light irradiation. Detailed optical and photoelectrochemical characterization showed that the incorporating CBB and HTiO-NS widened the range of the visible-light response and improved the ability to separate the photo-induced charge carriers. The presence of HTiO-NS has increased the oxidative properties, possibly by charge separation in the heterojunction, which facilitated the generation of superoxide and hydroxyl radicals. A possible reaction pathway for the photocatalytic oxidation of BnOH to BzH and BzA was also suggested. Furthermore, through scavenger experiments, we found that the photogenerated h+, e− and •O2− play an essential role in the BnOH photooxidation, while the •OH have a minor effect on the reaction. This work may provide a strategy for using HTiO-NS-based photocatalyst to enhance the charge carrier migration and photocatalytic performance of CBB. [ABSTRACT FROM AUTHOR]

[Display omitted] Tin dioxide (SnO 2) is a promising alternative material to graphite anode, but the large volume change induced electrode pulverization issue has limited its application in lithium-ion batteries (LIBs). In contrast, titanium dioxide (TiO 2) anode shows high structure stability upon lithium insertion/extraction, but with low specific capacity. To overcome their inherent disadvantages, combination of SnO 2 with TiO 2 and highly conductive carbon material is an effective way. Herein, we report a facile fabrication method of carbon-coated SnO 2 /TiO 2 nanowires (SnO 2 /TiO 2 @C) using tin titanate nanowires as precursor, which are prepared by reacting SnCl 2 ·2H 2 O with layered sodium titanate (Na 2 Ti 3 O 7) nanowires in the aqueous solution though the ion exchange between Sn2+ and Na+. After annealing under argon atmosphere, the hydrothermally carbon-coated tin-titanate nanowires decompose, forming a unique hybrid structure, where ultrafine SnO 2 nanoparticles are uniformly embedded within the TiO 2 substrate with carbon coating. Consequently, the SnO 2 /TiO 2 @C nanowires demonstrate excellent lithium storage capacity with high pseudocapacitance contribution, excellent reversible capacity, and long-term cycling stability (673.7/510.5 mAh/g at 0.5/1.0 A/g after 250/800 cycles), owing to the unique hybrid structure, as the well-dispersion of ultra-small SnO 2 within TiO 2 nanowire substrate with simultaneous carbon coating efficiently suppresses the volume changes of SnO 2 , provides abundant reactive sites for lithium storage, and enhances the electrical conductivity with shortened ion transport distance. [ABSTRACT FROM AUTHOR]

The partial substitution of Bi site by Tm ion makes new 4 f and 4 d energy levels below the CB, which can capture and store electrons in shallow traps, synchronously two-dimensional nanoplates of Bi 4 Ti 3 O 12 can transform into ultrathin nanosheets after incorporating Tm ions, thanks to the lower crystal surface energy. [Display omitted] In this study, we prepared two-dimensional Bi 4 Ti 3 O 12 nanosheets doped with rare earth ions. The experimental results show that Bi 4- x Tm x Ti 3 O 12 exhibits the highest reduction performance among various rare earth doped Bi 4 Ti 3 O 12 materials, with a CO yield of 7.25 μmol g−1h−1. Furthermore, a delayed reaction in Bi 3.97 Tm 0.03 Ti 3 O 12 is observed upon a cessation of light irradiation. Theoretical calculations reveal that the introduction of Tm ion not only reduces the surface energy of (0 0 1) plane and make it preferential growth in Bi 4 Ti 3 O 12 , but also brings the intervening energy level of Tm ion (4 f and 4 d mixed orbital), which is closer to the conduction band of Bi 4 Ti 3 O 12 and facilitates charge carrier accumulation in trap states. The electrons retained in the shallow traps promote the hysteresis reaction following a cessation of illumination. This work provides further insights into elucidating precise reduction reaction mechanisms underlying rare earth dopant on photocatalysts. This research provides enhanced insights into unraveling the precise reduction reaction mechanisms influenced by rare earth dopants in photocatalysts. [ABSTRACT FROM AUTHOR]

Inline (or in situ) photon density wave spectroscopy was used to monitor the disintegration of secondary titania particles into their primary particles. Photon density wave spectroscopy can be applied to determine the reduced scattering coefficient μs′$\mu _{\mathrm{s}}^{\prime}$ of a dispersion without dilution or calibration, and thus enables process analysis in materials that are usually unsuitable for established particle characterization techniques. In this work, amorphous titania particles were precipitated from tetraethyl orthotitanate in ethanol by addition of water in presence of different alkali metal salts (NaCl, KCl, CsCl, K2SO4) with concentrations between 0 and 1.6 mM. The present results suggest that the synthesized titania secondary particles disintegrate into their primary particles if the electrostatic repulsion between the primary particles is promoted. This can be achieved by an increased alkali chloride concentration in the synthesis or by addition of larger alkali metal ions. In contrast, the particles are only weakly charged upon addition of sulfate ions, and the disintegration stops. The conclusions drawn from photon density wave spectroscopy results are supported by gravimetric determination of the particle yield, dynamic light scattering measurements, zeta‐potential measurements, and electron micrographs. Additionally, the disintegration was driven to completion by addition of hydrochloric acid to create a transparent suspension of titania primary particles as small as 4.7 nm. [ABSTRACT FROM AUTHOR]

Potassium hexatitanate whiskers (PHWs, K 2 Ti 6 O 13) are generally slender, with diameters of about 1 μm, which falls under the category of inhalable particles. Producing large-diameter rod-shaped K 2 Ti 6 O 13 is necessary to prevent the environmental and human health threats posed by inhalable fibers. We report a new synthesis approach, via spherical agglomeration, which separates the nucleation stage from the nuclei agglomeration and growth stages of the calcination process resulting in the growth of the K 2 Ti 6 O 13 micro-rods with large diameter. From thermogravimetric analysis, we deduced the critical temperature for generating K 2 Ti 6 O 13 nuclei in the melt phase to be around 800 °C; this was referred to as the nucleation stage. The absorption of K 2 O on different facets of the growing crystal nuclei was used to control the nuclei agglomerate in a subsequent step. K 2 O acted as a binding agent to agglomerate the nuclei in the melt phase and transforms the finer agglomerate nuclei into large diameter micro-rods similar to the bridging agents employed in spherical agglomeration technique. K 2 Ti 6 O 13 micro-rods with large diameters of up to 8.3 μm were produced. [ABSTRACT FROM AUTHOR]

To address the dilemma of the stiffness and toughness properties of high-density polyethylene (HDPE) composites, titanate coupling agent-treated CaCO3 nanoparticles (nano-CaCO3) and ethylene–octene copolymer (POE) were utilized to blend with HDPE to prepare ternary nanocomposites via a two-sequence-step process. Meanwhile, a one-step process was also studied as a control. The obtained ternary nanocomposites were characterized by scanning electron microscopy (SEM), Advanced Rheometrics Expansion System (ARES), Dynamic Mechanical Analysis (DMA), wide-angle X-ray diffraction analysis (WXRD), and mechanical test. The SEM results showed one or two CaCO3 nanoparticles were well-encapsulated by POE and were uniformly dispersed into the HDPE matrix to form a core–shell structure of 100–200 nm in size by the two-step process, while CaCO3 nanoparticles were aggregated in the HDPE matrix by the one-step method. The result of the XRD showed that the nano-CaCO3 particle played a role in promoting crystallization in HDPE nanocomposites. Mechanical tests showed that the synergistic effect of both the POE elastomer and CaCO3 nanoparticles should account for the balanced performance of the ternary composites. In comparison with neat HDPE, the notched impact toughness of the ternary nanocomposites of HDPE/POE/nano-CaCO3 was significantly increased. In addition, the core–shell structure absorbed the fracture impact energy and prevent further propagation of micro-cracks, thus obtaining a higher notched Izod impact strength. [ABSTRACT FROM AUTHOR]

Outstanding materials and novel device structures are key factors in satisfying the increasing demand for energy storage. Li‐ion capacitors, as one typical model of asymmetric supercapacitors, benefit from the battery's ultrahigh specific energy and supercapacitor's superlarge specific power to meet the balanced electrochemical energy storage requirements. The inherent and irreplaceable advantages make spinel lithium titanate an optimal candidate for power batteries and Li‐ion capacitors. However, upstream market volatility, including price spikes and supply shortages, tremendously threatens spinel lithium titanate's production, sale, and application. Lithium hydroxide hydrate is an alternative raw material to synthesize spinel lithium titanate synthesis, which can help address these concerns. The indirect production path generates high‐quality lithium carbonate as an intermediate product. Spinel lithium titanate is synthesized preferably via another economically and technically more efficient method that skips the isolation step after carboxylation. The electrochemical performance of the resulting spinel lithium titanate is evaluated to be better than that of commercial competitors. The spinel lithium titanate negative electrode‐based lithium‐ion capacitor achieves a specific energy of 89.5 Wh kg−1. These results demonstrate the success of efforts to find a feasible and affordable synthesis route to mitigate market risks. [ABSTRACT FROM AUTHOR]

In this study, a series of rare-earth titanates with the general formula Re2TiO5 (Re = Er, Tm, Yb, and Lu) were synthesized and their microwave dielectric properties were reported. The impact of differences in rare-earth cation radii on the structure and dielectric properties was systematically analyzed. The findings indicated that ceramics of Re2TiO5 (Re = Er, Tm, Yb, and Lu) were crystallized into a cubic structure with space group Fd-3m, as confirmed by Rietveld refinement and selected-area electron diffraction patterns. The rare-earth elements were analyzed for their impact on microwave dielectric properties, considering factors such as ionic polarizability, packing fraction, and bond valence theory. The resulting materials exhibited excellent microwave dielectric properties with a low permittivity (6.95-7.21), high-quality factors (19 451-20 115 GHz), and low positive temperature coefficient of resonance frequency (19.34-20.90 ppm/°C). The origin of low permittivity was elucidated through the analysis of bond length, X-ray photoelectron spectroscopy, and impedance spectroscopy. This series of titanates exhibited unusually low permittivity characteristics in the microwave frequency range, which couldmeet the low signal transmission delay requirements in wireless communication. [ABSTRACT FROM AUTHOR]

Wide bandgap semiconductor-based photocatalysts are usually limited by their low solar energy conversion efficiency due to their limited absorption solar wavelength, their rapid surface recombination of the photogenerated electron–hole pairs, and their low charge-carrier mobility. Here, we report a novel stepwise solution synthesis for achieving a new photocatalytic core–shell consisting of a titanate nanowire/reduced graphene oxide shell (or titanate/rGO) 1D-nanocomposite. The new core–shell nanocomposite maximized the specific surface area, largely reduced the charge transfer resistance and reaction energy barrier, and significantly improved the absorption of visible light. The core–shell nanocomposites' large on/off current ratio and rapid photo-responses boosted the photocurrent by 30.0%, the photocatalysis rate by 50.0%, and the specific surface area by 16.4% when compared with the results for the pure titanate nanowire core. Our numerical simulations support the effective charge separation on the new core–shell nanostructure, which can help further advance the novel photocatalysis. [ABSTRACT FROM AUTHOR]

The n -type titanate heterojunction with p -type transition metal oxides reduces the recombination effect (e−/h+) and improves the magnetic, electronic, and luminescent properties. Based on these related properties, the synthesis of nanocomposite sodium-cobalt titanate nanotube and iron oxide (Co-NaTiNT@FeO) was performed using titanium dioxide (polymorphic mixture: brookite, anatase and rutile), cobalt nitrate hexahydrate and iron oxide (FeO). The synthesized materials were characterised by X-ray diffraction (XRD), Raman and infrared (IR) spectroscopies, thermogravimetry and differential (TG-dTG), transmission electron microscopy (TEM) and scanning (SEM), X-ray photoelectron spectroscopy (XPS), adsorption/desorption of N 2 by Brunauer-Emmett-Teller (BET) method, Ultraviolet–Visible (UV–Vis) by diffuse reflectance spectroscopy (DRS), photoluminescence (PL), and vibrating sample magnetometer (VSM). The results revealed the presence of Co2+ ions in the lamellar region of the nanotubes, in addition to verifying that there was no collapse of the nanotubes before and after the anchoring of the FeO nanoparticles. Using the XPS technique, the presence of 2.49 wt% of Fe (2p), as well as 1.55 wt% of Co (2p), was identified; these elements favoured the band gap reduction from 3.61 to 2.66 eV compared to sodium titanate nanotube (NaTiNT); in addition, they favoured the emergence of emissions associated with the red, yellow, and orange colours, described through PL. The surface area of the composite changed from 197.00 to 210.46 m2 g−1, possibly due to the homogeneous presence of anchored superparamagnetic FeO nanoparticles. Finally, the results were consistent with the proposal for the synthesis of Co-NaTiNT@FeO, which had improvements in its properties, especially its magnetic properties. [Display omitted] • TiO2 nanoparticles with phases mixture: anatase, rutile, brookite. • Direct synthesis of Co-doped Sodium Titanate Nanotubes (Co-NaTiTN) via alkaline hydrothermal method. • Superparamagnetic heterojunction of Co-NaTiNT with FeO nanoparticles. • Photocatalytic activity of heterojunction Co-NaTiNT@FeO. • Magnetic behaviour of heterojunction Co-NaTiNT@FeO. [ABSTRACT FROM AUTHOR]

In this paper, we report on the solvothermal preparation and detailed characterization of pristine and intentionally doped zirconium dioxide (ZrO2) nanocrystals (NCs, ~5 nm) with Eu3+ or Ti4+/Eu3+ ions using alkoxide precursors. The results indicated that the ZrO2 NCs were dominantly of a tetragonal phase (t-ZrO2) with a small proportion of monoclinic ZrO2 (m-ZrO2). The high purity of t-ZrO2 NCs could be synthesized with more Eu3+ doping. It was found that the as-obtained ZrO2 NCs contain some naturally present Ti4+ ions originating from precursors, but were being overlooked commonly, and some carbon impurities produced during synthesis. These species showed distinct photoluminescence (PL) properties. At least two types of Eu3+, located at low- and high-symmetry sites (probably sevenfold and eightfold oxygen coordination), respectively, were demonstrated to build into the lattice structure of t-ZrO2 NCs together. The cationic dopants were illustrated to be distributed non-randomly over the sites normally occupied by Zr, while Ti impurities preferentially occupied the sites near the low-symmetry site of Eu3+, yielding efficient energy transfer from the titanate groups to the neighboring Eu3+. Luminescence nanothermometry could measure temperature in a non-contact and remote way and could find great potentials in micro/nano-electronics, integrated photonics, and biomedicine. On the basis of the dual-emitting combination strategy involving the white broadband CT (Ti3+→O−) emissions of the titanate groups and red sharp Eu3+ emissions, t-ZrO2:Eu3+ nanophosphors were demonstrated to be ratiometric self-referencing optical thermometric materials, with a working range of 130–230 K and a maxima of relative sensitivity of ~1.9% K−1 at 230 K. [ABSTRACT FROM AUTHOR]

Nickel titanate (NiTiO3) semiconductors and graphitic carbon nitride (g-C3N4) have attracted great attention as photocatalysts in the degradation of environmental pollutants because of their visible-light-driven activity. But the utilizations of both semiconductors are limited by their low specific surface area. In this study, a nano-NiTiO3/g-C3N4 photocatalyst was successfully synthesized by optimizing the preparation method of photocatalyst precursors. Compared with the bulk g-C3N4 and bulk NiTiO3/g-C3N4 composite photocatalysts, the nano-NiTiO3/g-C3N4 composite catalyst displayed a larger specific surface area, a more abundant pore size structure, and superior carrier separation capabilities. According to the pseudo-first-order, the degradation rate of MB was more than 2.5–19.7 times higher than that of previous studies. The superoxide radicals (·O2−) and holes (h+) played significant roles in the photocatalytic reaction of MB. This study provides a new idea for the synthesis of photocatalysts and the improvement in photocatalytic performance. [ABSTRACT FROM AUTHOR]

A novel finding that the electrochemical performance of the commercial lithium titanate (Li4Ti5O12, LTO) can be significantly improved by using a novel current collector of CuI particles modified copper foil is reported for the first time in this work. Firstly, a large number of particles with well-defined shapes were prepared on the commercial copper foil surface via a very simple soaking process, in which the soaking solution contained only CuSO4, H2SO4 and [Bmim]I. As indicated by the XRD and XPS measurements, the particles observed on the surface of the copper foil were identified as CuI particles. That is, CuI particles modified copper foils (denoted as CuI/Cu) were successfully prepared at room temperature. CuI/Cu prepared in the presence of 0.4, 0.6 and 0.8 g of [Bmim]I were nominated as CF (copper foil) a, b and c, respectively. Inconceivably, as compared to the conventional LTO electrode, the LTO electrodes assembled using the newly prepared CFs exhibited a significantly improved electrochemical performance, i.e., all as-prepared CFs showed an evident promoting effect on the electrochemical performance of the traditional LTO electrodes. For instance, the initial discharge capacity (DC) of the LTO electrode assembled using CF b (called electrode b) at 0.2 C was 307 mAh g−1, which was about 1.86 times higher than that of the LTO electrode prepared using the conventional copper foil current collector (165 mAh g−1). Particularly, as the applied current rate was as high as 10 C, the DC value of electrode b (117 mAh g−1), even after 100 cycles, was still about 2.54 times that of the traditional LTO electrode (46 mAh g−1). In this preliminary work, a new method for preparing CuI particles was developed, along with a novel approach to significantly improve the electrochemical properties of the commercial LTO electrode. The method did not require any strong oxidants or reducing agents, nor did it demand any additional energy expenditure during the preparation of CuI particles. Moreover, the approach did not require any changes in the assembly procedure for the LTO electrodes being studied. This work was very meaningful for the development of the CuI-related research field as well as for the electrochemical performance improvement of LTO-based lithium-ion batteries (LIBs). [ABSTRACT FROM AUTHOR]

In this paper, we have mainly reported the preliminary structural analysis and the frequency–temperature dependence of the dielectric and electrical properties of ceramic technology-fabricated Sn-modified bismuth titanate with a chemical composition of Bi4Ti2.9Sn0.1O12 electro-ceramic at room temperature. The compound is synthesized in a single-phase orthorhombic structure, as shown by the analysis of the X-ray diffraction pattern and data at room temperature. Detailed studies of dielectric and electrical properties in a wide temperature range (25 to 400°C) at different frequencies ranging from 1 to 1000 kHz have provided many important properties of the prepared sample. The dielectric constant and tangent loss at temperature 400°C and frequency 1 kHz are found to be 3 × 103 and 1.6, respectively. It was possible to calculate the contributions of the grains and grain boundaries to the overall resistance and capacitance of the synthesized material using Nyquist plots. The types of conduction mechanisms have been studied from an ac-conductivity study of the material. The J–E characteristics of the prepared sample which have slopes closer to 1, support the Ohmic behaviour. The study of the electric field and frequency dependence of electric polarization through hysteresis loops has confirmed the ferroelectric behaviour of the studied material at room temperature. Some experimental data obtained here suggest that the material may be useful as an electronic component in electronic industries. [ABSTRACT FROM AUTHOR]

Bioactive materials may be applied in tissue regeneration, and an example of such materials are wound dressings, which are used to accelerate skin healing, especially after trauma. Here, we proposed a novel dressing enriched by a bioactive component. The aim of our study was to prepare and characterize poly(vinyl alcohol) films modified with strontium titanate nanoparticles. The physicochemical properties of films were studied, such as surface free energy and surface roughness, as well as the mechanical properties of materials. Moreover, different biological studies were carried out, like in vitro hemo- and cyto-compatibility, biocidal activity, and anti-biofilm formation. Also, the degradation of the materials' utilization possibilities and enzymatic activity in compost were checked. The decrease of surface free energy, increase of roughness, and improvement of mechanical strength were found after the addition of nanoparticles. All developed films were cyto-compatible, and did not induce a hemolytic effect on the human erythrocytes. The PVA films containing the highest concentration of STO (20%) reduced the proliferation of Eschericha coli, Pseudomonas aeruginosa, and Staphylococcus aureus significantly. Also, all films were characterized by surface anti-biofilm activity, as they significantly lowered the bacterial biofilm abundance and its dehydrogenase activity. The films were degraded by the compost microorganism. However, PVA with the addition of 20%STO was more difficult to degrade. Based on our results, for wound dressing application, we suggest using bioactive films based on PVA + 20%STO, as they were characterized by high antibacterial properties, favorable physicochemical characteristics, and good biocompatibility with human cells. [ABSTRACT FROM AUTHOR]

This study is dedicated to a comprehensive investigation into the influence of barium strontium titanate (BST) doping on the microstructure, dielectric properties, and electrical behavior of calcium copper titanate (CCTO) ceramics. The research involves a systematic analysis of a series of (1-x) CaCu3Ti4O12 - x Ba0.6Sr0.4TiO3 [(1-x) CCTO/x BST] composite samples, with varying BST ratios (x = 0, x = 0.025, x = 0.075, x = 0.15, and x = 0.2). These composites were synthesized through the solid-state reaction method and subsequently sintered at 1050 °C for a duration of 12 h. The investigation provides detailed insights into microstructural features, dielectric characteristics, and electrical responses, thereby unraveling the intricate correlations between BST content and the resultant material properties. Notably, the sample with x = 0.025 exhibited the highest dielectric constant (εr ≈ 2.71 × 104) and the lowest dielectric loss (tanδ ≈ 0.052) at a frequency of 1 kHz. Furthermore, the optimized composition (x = 0.025) demonstrated exceptional breakdown electric field (Eb ≈ 1284 V/cm) and notable grain boundary resistance (Rgb ≈ 8.8 × 106 Ω). These findings collectively contribute to an enhanced understanding of the impact of BST doping on the distinct characteristics of CCTO ceramics, opening avenues for tailored applications in advanced electronic devices and energy storage systems. [ABSTRACT FROM AUTHOR]

Pyroelectric materials are naturally electrically polarized and exhibits a built-in spontaneous polarization in their unit cell structure even in the absence of any externally applied electric field. These materials are regarded as one of the ideal detector elements for infrared applications because they have a fast response time and uniform sensitivity at room temperature across all wavelengths. Crystals of the perovskite lead titanate (PbTi O 3 ) family show pyroelectric characteristics and undergo structural phase transitions. They have a high Curie temperature (the temperature at which the material changes from the ferroelectric (polar) to the paraelectric (nonpolar) phase), high pyroelectric coefficient, high spontaneous polarization, low dielectric constant, and constitute important component materials not only useful for infrared detection, but also with vast applications in electronic, optic, and MEMS devices. However, the preparation of large perfect and pure single crystals PbTi O 3 is challenging. Additionally, difficulties arise in the application of such bulk crystals in terms of connection to processing circuits, large size, and high voltages required for their operation. In this part of the review paper, we explain the electrical behavior and characterization techniques commonly utilized to unravel the pyroelectric properties of lead titanate and its derivatives. Further, it explains how the material preparation techniques affect the electrical characteristics of resulting thin films. It also provides an in-depth discussion of the measurement of pyroelectric coefficients using different techniques. [ABSTRACT FROM AUTHOR]

Recently, visible-light-driven persulfate-based advanced oxidation processes (AOPs) employing heterogeneous catalysts to generate sulfate radicals (SO4·−) from peroxymonosulfate (PMS, HSO5−) have been extensively investigated in the field of water remediation, to remove organic contaminants. In this study, CeO2/2.0STO visible light photocatalyst with pore structure was synthesized by sol–gel method and impregnation method for photocatalytic methylene blue (MB) degradation via PMS activation. The MB degradation efficiency exhibited a high level at a broad pH range 2–12, and the presence of various organic matter and natural inorganic ions had no significant impact. When the PMS dosage was at 0–0.1 mM, the MB degradation efficiency still reached 100% within 40 min, indicating that the photocatalyst has high PMS utilization rate. The catalyst has high catalytic degradation efficiency on several typical dyes. Reused for 5 cycles, the catalytic activity, crystal form and three-dimensionally ordered macroporous (3DOM) structure of the photocatalyst without change significantly, and the leaching ratios of Sr, Ti and Ce were just under 0.1%. CeO2/2.0STO hole confinement effects and the synergistic effect between strontium titanate (SrTiO3) and ceria (CeO2) result in the excellent photocatalytic performance. The catalyst surface abundant pores absorb MB molecules into its interior, shortening the diffusion path of ROSs and improving contact efficiency. The formation of SrTiO3 and CeO2 heterojunction, which enhanced the separation of photogenerated electron/hole pairs. Experimental results confirmed that 1O2, SO4−·, ·O2− and ·OH all contributed to the MB degradation. [ABSTRACT FROM AUTHOR]

The solid‐state transformation behavior of cobalt dititanate (CoTi2O5) has been studied at different temperatures. The starting structure consisted of a duplex (1:1 molar) mixture of CoTiO3 and TiO2 grains. A seed layer of CoTi2O5 grains was incorporated at the upper surface of the green, precursor powder samples. Cobalt dititanate is a member of the pseudobrookite family (Cmcm, orthorhombic); it is an entropy‐stabilized compound, hence is stable only at elevated temperatures (T > 1140°C). It was observed that transformation initiated adjacent to the seed layer. First, a narrow layer of CoTi2O5 forms at the diphase boundaries, creating a 3‐D network that propagates at a constant velocity through the structure. The velocity of the reaction front follows an Arrhenius dependence on temperature. Both the rates of nucleation and growth increase with increasing temperature. At 1300°C, the velocity was estimated to be in excess of 10 mm/h. The progression of the reaction front was modelled based on a discontinuous template growth mechanism, with enhanced diffusion along the boundary between the product and reactant phases. The activation energy derived for boundary diffusion was 475 ± 69 kJ/mol. Behind the reaction front, the microstructure consists of a continuous matrix of CoTi2O5, with isolated remnant grains of CoTiO3 and TiO2. Further transformation occurs more slowly by solid‐state diffusion through the CoTi2O5 phase. Studies of the crystallographic orientation of the CoTi2O5 phase showed that it was pseudo‐ single crystal, with a preferred growth direction of [100]. The system exhibits novel features, which have not been reported previously for ceramic systems. [ABSTRACT FROM AUTHOR]

The rGO/TiO2 nanocomposite was synthesized using graphene oxide and butyl titanate as raw materials in a hydrothermal process. Various samples were produced by varying the duration of the hydrothermal treatment. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy were used to examine the nucleation and growth processes of anatase in the hydrothermal process from the thermodynamics and kinetics perspectives. The structural evolution of titanium dioxide/reduced graphene oxide with hydrothermal time was analyzed. The crystallite size as well as the particle size of the TiO2, rGO and TiO2/rGO decreases with increase in the hydrothermal reaction time. [ABSTRACT FROM AUTHOR]

In our present work, we report the synthesis of Sb-doped SnO2-coated TiO2 (TiO2@Sb-SnO2) conductive nanocomposites by hydrothermal method. Firstly, titanate whiskers were hydrothermally synthesized at 175 °C using sodium hydroxide and metatitanic acid as starting materials with a molar ratio of 4:1. And then, the TiO2@Sb-SnO2 nanocomposites were hydrothermally synthesized with the use of the as-synthesized titanate whiskers, tin tetrachloride, and antimony trichloride as starting materials at 185 °C. In the hydrothermal reaction process, Sb-doped SnO2 nanoparticles enhanced the phase transition from titanate to rutile TiO2. The oxidation states of tin and antimony elements are Sn4+, Sb5+, and Sb3+, respectively. TEM and HRTEM analyses indicated that the Sb-doped SnO2 nanoparticles with an average particle size of around 1.5 nm were coated on the surfaces of TiO2 nanoparticulates with an average particle size of around 20 nm. The TiO2@(1%)Sb-(10%)SnO2 nanocomposites had a minimum electric resistivity of 5.97 × 103 Ω·cm. Filling of the TiO2@Sb-SnO2 nanocomposites increased the electric conductivity of waterborne polyester films, endowing the polyester films with static electron dissipativity. [ABSTRACT FROM AUTHOR]

Nowadays, there have been much consideration to develop eco-friendly advanced materials, which have many applications in the field of multiferroics, sensors, actuators, magnetically modulated transducer devices, etc. Hence, the preparation of lead-free based multifunctional materials has now become of great interest to researchers. The present study reports the synthesis and study of structural, dielectric, and multiferroics characteristics of (Bi 0.8 Nd 0.2)(Fe 0.5 Ti 0.5)O 3 material. The compound was synthesized using a conventional solid-state reaction method (calcination at 950 °C). The X-ray diffraction analysis of the compound confirms the single-phase formation with orthorhombic symmetry. The surface morphology of the material has been examined by the field emission scanning electron microscopy (FESEM) method, which shows uniform grain distribution in the microstructural image. Grains were to be found of different sizes with few voids. Energy dispersive X-ray (EDX) shows the purity of the sample with an equivalent amount of weight and atomic percentage. Dielectric and impedance analysis have been investigated in a wide range of frequencies and temperatures. Frequency-dependent ac-conductivity obeys Jonscher's universal power law. The P-E loop tracer was used to study the ferroelectric nature of the sample. Magnetic field-dependent magnetization is measured at room temperature by a vibrating sample magnetometer (VSM). The current study provides efficient, eco-friendly, and interesting results for further application purposes. [ABSTRACT FROM AUTHOR]

Pyroelectric materials, are those materials with the property that in the absence of any externally applied electric field, develop a built-in spontaneous polarization in their unit cell structure. They are regarded as ideal detector elements for infrared applications because they can provide fast response time and uniform sensitivity at room temperature over all wavelengths. Crystals of the perovskite Lead Titanate (PbTi O 3 ) family show pyroelectric characteristics and undergo structural phase transitions. They have a high Curie temperature (the temperature at which the material changes from the ferroelectric (polar) to the paraelectric (nonpolar) phase), high pyroelectric coefficient, high spontaneous polarization, low dielectric constant, and constitute important component materials not only useful for infrared detection, but also with vast applications in electronic, optic, and Micro-electromechanical systems (MEMS) devices. However, the preparation of large perfect, and pure single crystals of PbTi O 3 is challenging. Additionally, difficulties arise in the application of such bulk crystals in terms of connection to processing circuits, large size, and high voltages required for their operation. A number of thin film fabrication techniques have been proposed to overcome these inadequacies, among which, magnetron sputtering has demonstrated many potentials. By addressing these aspects, the review article aims to contribute to the understanding of the challenges in the field of pyroelectric materials, highlight potential solutions, and showcase the advancements and potentials of pyroelectric perovskite series including PbZrTiO3 (PZT), P b x C a 1 − x (PZN-PT), etc. for which PbTi O 3 is the end member. The review is presented in two parts. Part 1 focuses on material aspects, including preparation methods using magnetron sputtering and material characterization. We take a tutorial approach to discuss the progress made in epitaxial growth of lead titanate-based ceramics prepared by magnetron sputtering and examine how processing conditions may affect the crystalline quality of the growing film by linking to the properties of the substrate/buffer layer, growth substrate temperature, and the oxygen partial pressure in the gas mixture. Careful control and optimization of these parameters are crucial for achieving high-quality thin films with desired structural and morphological characteristics. [ABSTRACT FROM AUTHOR]

A multi-step procedure was effectively employed to synthesize innovative three-dimensional (3D) heterostructures encompassing sodium titanate (Na2Ti3O7) nanowire cores, an intermediate resorcinol–formaldehyde (RF) layer, and outer silver (Ag) nanoparticle sheaths, referred to as Na2Ti3O7@RF@Ag heterostructures. Initially, a one-step hydrothermal technique facilitated the direct growth of single-crystal Na2Ti3O7 nanowires onto a flexible Ti foil. Subsequently, a two-step wet chemical process facilitated the sequential deposition of an RF layer and Ag nanoparticles onto the Na2Ti3O7 nanowires at a low reaction temperature. Optimal concentrations of silver nitrate and L-ascorbic acid can lead to the cultivation of Na2Ti3O7@RF@Ag heterostructures exhibiting heightened surface-enhanced Raman scattering (SERS), which is particularly beneficial for the detection of rhodamine B (RhB) molecules. This phenomenon can be ascribed to the distinctive geometry of the Na2Ti3O7@RF@Ag heterostructures, which offer an increased number of hot spots and surface-active sites, thereby showcasing notable SERS enhancement, commendable reproducibility, and enduring stability over the long term. Furthermore, the Na2Ti3O7@RF@Ag heterostructures demonstrate remarkable follow-up as first-order chemical kinetic and recyclable photocatalysts for the photodecomposition of an RhB solution under UV light irradiation. This result can be attributed to the enhanced inhibition of electron–hole pair recombination and increased surface-active sites. [ABSTRACT FROM AUTHOR]

In this study, lead-free bismuth sodium titanate (BNT; Bi0.5Na0.5TiO3) powder was synthesized using wet precipitation. The sintering behavior and dielectric properties of the BNT ceramics were investigated in terms of the sintering temperature. Titanium isopropoxide, sodium nitrate, and bismuth nitrate were used as starting materials. A titanium peroxo complex (TPC) solution was synthesized using titanium hydroxide, nitric acid, and hydrogen peroxide. A clear Bi-Na-Ti precursor solution was obtained by mixing the TPC, sodium, and bismuth nitrate solutions. The pH of the precursor solution was increased to 9 using NaOH and a white powder was precipitated. A spherical and pyrochlore phase-free BNT powders were obtained by calcining the white precipitate above 600°C for 3 h. Particle size analysis and SEM observations revealed that the BNT powder calcined at 700°C exhibited homogeneous distribution with particle size less than 300 nm. The sinterability of the BNT ceramic prepared through wet precipitation was significantly enhanced compared to that of the BNT powder prepared via the solid-state reaction of sodium carbonate, bismuth oxide, and titanium oxide powders. [ABSTRACT FROM AUTHOR]

Agricultural waste fiber has huge utilization potential due to its abundant sources, renewability, and low recycling costs. In this process, up to 30 wt% tobacco stalk fiber (TSF) was compounded with high‐density polyethylene (HDPE) and interfacial modifiers using a grinder, melting‐blending mixer, and injection molding machine to prepare environmentally friendly TSF/HDPE composites, which have excellent mechanical properties and good water resistance. On this basis, the interfacial compatibility between TSF and HDPE was enhanced by adding a silane coupling agent KH550, titanate coupling agent 201, and maleic anhydride grafted polyethylene (MA‐g‐PE), which led to the improvement of mechanical properties of composites. The mechanical properties of the composites with 2% MA‐g‐PE were the best, while the tensile strength and flexural strength increased by 72% and 38%, respectively, compared with the unmodified composites. Fourier transform infrared (FTIR) spectroscopy showed that TSF was modified by different coupling agents and new chemical bonds were formed. The scanning electron microscopy images showed that the interfacial compatibility between TSF and HDPE was improved by the interface modifiers. This work confirms that it is possible to use TSF to prepare composites and provides a new way for resource utilization of tobacco stalk fiber. Highlights: TSF was incorporated into composites, boosting material sustainability.The interface compatibility between TSF and HDPE was greatly improved.Thermal and water absorption analysis can be used for composites design.Composites modified by 2 wt% MA‐g‐PE had optimal comprehensive properties. [ABSTRACT FROM AUTHOR]

Thin films of strontium titanate, which have nonlinear properties that are promising for microwave applications, were grown on a polycrystalline aluminum oxide substrate using magnetron sputtering and high-temperature annealing. It was shown that the improvement of the film structure with an increase in the deposition temperature was clearly correlated with both an increase in nonlinearity and an improvement in the loss level. A capacitor based on an SrTiO3 film deposited at a deposition temperature of 900 °C and subjected to annealing demonstrated a tunability of 46% with a loss tangent of 0.009–0.014 at a frequency of 2 GHz. This was the first successful attempt to form a planar SrTiO3 capacitor on an alumina substrate, which exhibited a commutation quality factor of above 3000 in the microwave range. [ABSTRACT FROM AUTHOR]

Leucoxene-quartz concentrate is a large-tonnage by-product of development of the Timan oil-titanium field (oil-saturated sandstones) which is not commercially used at present. High content of titanium compounds (to 50 % by weight) and lack of industrial, cost-effective, and safe technologies for its processing determine a high relevance of the work. Conventional processing technologies allow increasing the concentration of TiO2, but they are only a preparation for complex and hazardous selective chlorination. The process of pyrometallurgical conversion of leucoxene-quartz concentrate into aluminium and magnesium titanates was investigated. It was ascertained that the temperature of solid-phase reaction in Al2O3-TiO2-SiO2 system necessary for the synthesis of aluminium titanate (Al2TiO5) is 1,558 °С, and for MgO-TiO2-SiO2 system – 1,372 °С. Scaling up the process made it possible to synthesize a significant number of samples of titanate-containing products, the phase composition of which was studied by X-ray phase analysis. Two main phases were identified in the products: 30 % aluminium/magnesium titanate and 40 % silicon dioxide. In products of pyrometallurgical processing in the presence of aluminium, phases of pseudobrookite (3.5 %) and titanite (0.5 %) were also found. It was ascertained that in magnesium-containing system the formation of three magnesium titanates is possible: MgTiO3 – 25, Mg2TiO4 – 35, MgTi2O5 – 40 %. Experiments on sulphuric acid leaching of samples demonstrated a higher degree of titanium compounds extraction during sulphuric acid processing. An integrated conceptual scheme for processing leucoxene-quartz concentrate to produce a wide range of potential products (coagulants, catalysts, materials for ceramic industry) was proposed.

A sol-gel method was applied to prepare sodium titanate samples with different Na/Ti molar ratios, that is, n(Na)/n(Ti) = 2:3 (Na2Ti3), 2:6 (Na2Ti6) and 2:9 (Na2Ti9). Nano-sized Na2Ti6O13 was the main substance in all the samples, while Na2Ti3 contained a minor proportion of Na4Ti5O12, and rutile phase TiO2 was a minor component in Na2Ti9. The adsorption-desorption isotherms of the samples were regarded as an International Union of Pure and Applied Chemistry Type IV isotherm for mesoporous materials. The band gap energies for Na2Ti3, Na2Ti6 and Na2Ti9 were calculated to be 3.28, 3.15 and 3.06 eV, respectively. The productivity of hydroxyl radicals on the sodium titanates was in the sequence Na2Ti9 > Na2Ti6 > Na2Ti3. The original ofloxacin molecules were nearly completely degraded after 70 min of reaction in the presence of Na2Ti6 and Na2Ti9, while the degradation efficiency was only 54.7% for Na2Ti3. The reaction rate constants for ofloxacin degradation occurred on Na2Ti3, Na2Ti6 and Na2Ti9 were calculated to be 0.00693, 0.0154 and 0.0187 min-1, respectively. A total of 88.1% of the original activity of Na2Ti6 was maintained in the fifth reaction cycle. [ABSTRACT FROM AUTHOR]

Dual modification enabled by a thermally treated STO layer served multiple beneficial functions: 1) it prevented direct contact between the Ni-rich cathode and the organic electrolyte, thereby minimizing side reactions and enlarging the cathode lifespan; 2) it improved Li+ conductivity by defining clear Li-ion diffusion pathways, leading to low interfacial resistance and excellent electrochemical performance. [Display omitted] • Dual modifications are achieved with optimized thermal treatment of SrTiO 3 coated Ni-rich cathode material. • The specific capacity, cyclic stability and rate performance of Ni-rich cathode materials are significantly improved. • The SrTiO 3 coating not only protects NCM811 from parasitic reactions and facilitates Li+ diffusion enabled by the Ti interfacial doping. • The electrochemical polarization and internal cracking are reduced with the dual modification. Ni-rich layered structure ternary oxides, such as LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811), are promising cathode materials for high-energy lithium-ion batteries (LIBs). However, a trade-off between high capacity and long cycle life still obstructs the commercialization of Ni-rich cathodes in modern LIBs. Herein, a facile dual modification approach for improving the electrochemical performance of NCM811 was enabled by a typical perovskite oxide: strontium titanate (SrTiO 3). With a suitable thermal treatment, the modified cathode exhibited an outstanding electrochemical performance that could deliver a high discharge capacity of 188.5 mAh/g after 200 cycles under 1C with a capacity retention of 90%. The SrTiO 3 (STO) protective layer can effectively suppress the side reaction between the NCM811 and the electrolyte. In the meantime, the pillar effect provided by interfacial Ti doping could effectively reduce the Li+/Ni2+ mixing ratio on the NCM811 surface and offer more efficient Li+ migration between the cathode and the coating layer after post-thermal treatment (≥600 °C). This dual modification strategy not only significantly improves the structural stability of Ni-rich layered structure but also enhances the electrochemical kinetics via increasing diffusion rate of Li+. The electrochemical measurement results further disclosed that the 3 wt% STO coated NCM811 with 600 °C annealing exhibits the best performance compared with other control samples, suggesting an appropriate temperature range for STO coated NCM811 cathode is critical for maintaining a stable structure for the whole system. This work may offer an effective option to enhance the electrochemical performance of Ni-rich cathodes for high-performance LIBs. [ABSTRACT FROM AUTHOR]

With great optical, catalytic and electrical characteristics, titania (TiO 2) and TiO 2 -based titanates present many potential applications in chemical and photocatalysis, solar cells, electrochemical water splitting, chemical/gas sensing, among others. Herein, we show that lepidocrocite-based titanates of low-dimensional nanotubes, NTs, nanowires, NWs, and nanoribbons, NRs, can be synthesized near ambient conditions through a bottom-up approach starting with titanium carbide, TiC, nitride, TiN, or boride, TiB 2. Successful reactions were conducted at 95 °C in alkaline solutions of sodium hydroxide, NaOH, or potassium hydroxide, KOH, thereby producing NTs/NRs, and NWs, respectively. Such nanostructures self-assemble into fibrous structures that, in turn, form free flowing, mesoporous particles. The production of these materials from common binary Ti precursors under such relatively mild reaction conditions highlights a breakthrough in the efficient and scalable production of low-dimensional titanate materials. We synthesized and characterized these materials under various conditions and believe they present significant potential where similar titanate species have succeeded. [Display omitted] [ABSTRACT FROM AUTHOR]

Aurivillus oxide thin films with nanostructures attained much interest due to their structural stability, outstanding ferroelectric, and dielectric properties. This manuscript reports the influence of oxygen mixing percentage (OMP) on structural, nanomechanical, and microwave dielectric properties of strontium bismuth titanate (SrBi4Ti4O15) thin films. SrBi4Ti4O15 films were successfully fabricated on fused silica substrates at room temperature, followed by annealed in a microwave furnace. The crystalline nature and purity of the phase was identified by X-ray diffraction. Nanomechanical properties of the SrBi4Ti4O15 films were studied using nanoindentation and nanoscratch tests. The best nanomechanical (hardness ∼6.9 GPa, Young's modulus ∼120 GPa) properties were shown for films deposited around 50% of OMP. Microwave dielectric properties (dielectric constant and loss tangent at microwave frequencies 10 and 20 GHz) were extracted from the split postdielectric resonator technique. [ABSTRACT FROM AUTHOR]

With the development of electronic information technology, people have put forward more requirements for miniaturization and multifunctionality of electronic devices. Obtaining dielectric materials with good dielectric response is a research challenge. Calcium copper titanate (CCTO) ceramics have attracted widespread attention from researchers due to their high dielectric constant, good stability, and strong applicability. However, it has a significant dielectric loss, which limits its further development and application. Based on this, this paper systematically reviews the research progress of CCTO in terms of dielectric loss, focusing on the influence of different doping modification strategies on the dielectric loss characteristics. The selection of different sites, types, amounts, and properties of dopants has an important impact on dielectric loss, and controlling the grain size and grain boundary resistance can achieve low dielectric loss. The potential future development directions of CCTO mainly include the development of new doping strategies, research on doping modification mechanisms, and applications of materials in multiple fields. This work lays the foundation for the study of CCTO and its application in electronic devices, and is of great significance for the development of new materials and the improvement of their performance. [ABSTRACT FROM AUTHOR]

Nanosheets of layered perovskite-like oxides attract researchers as building blocks for the creation of a wide range of demanded nanomaterials. However, Ruddlesden–Popper phases are difficult to separate into nanosheets quantitatively via the conventional liquid-phase exfoliation procedure in aqueous solutions of bulky organic bases. The present study has considered systematically a relatively novel and efficient approach to a high-yield preparation of concentrated suspensions of perovskite nanosheets. For this, the Ruddlesden–Popper titanates HLnTiO4 and H2Ln2Ti3O10 (Ln = La, Nd) have been intercalated by n-alkylamines with various chain lengths, exposed to sonication in aqueous tetrabutylammonium hydroxide (TBAOH) and centrifuged to separate the nanosheet-containing supernatant. The experiments included variations of a wide range of conditions, which allowed for the achievement of impressive nanosheet concentrations in suspensions up to 2.1 g/L and yields up to 95%. The latter were found to strongly depend on the length of intercalated n-alkylamines. Despite the less expanded interlayer space, the titanates modified with short-chain amines demonstrated a much higher completeness of liquid-phase exfoliation as compared to those with long-chain ones. It was also shown that the exfoliation efficiency depends more on the sample stirring time in the TBAOH solution than on the sonication duration. Analysis of the titanate nanosheets obtained by means of dynamic light scattering, electron and atomic force microscopy revealed their lateral sizes of 30–250 nm and thickness of 2–4 nm. The investigated exfoliation strategy appears to be convenient for the high-yield production of perovskite nanosheet-based materials for photocatalytic hydrogen production, environmental remediation and other applications. [ABSTRACT FROM AUTHOR]

Sodium bismuth titanate (BNT)-based dielectric capacitors with excellent energy storage performance play an important role in electronics industry. (Sr 1.05 Bi 0.3)ScO 3 (SBS) is introduced into 0.85Bi 0.5 Na 0.5 TiO 3 -0.15NaNbO 3 (BNT-NN) to achieve co-regulation of phase and domain structure. With the introduction of SBS, the dominated pseudocubic phase accompanied by a small percentage of rhombohedral phase are tend to form, and thus induce nanodomain structure with high-density domain walls. Under the excitation of a bias voltage, the induced nanodomains are easier to switch and effectively reduce the residual polarization. Additionally, the homogeneous nanodomains with high-density domain walls will promote large negative built-in voltage which are favorable to rise of breakdown field strength, and thus, optimize the energy storage performance. The co-regulation of phase-domain structure provides an idea for designing ferroelectrics with good energy storage performance. [ABSTRACT FROM AUTHOR]

The interaction of an aqueous solution of strontium nitrate with magnesium-doped potassium titanate nanotubes synthesized by coprecipitation followed by hydrothermal treatment is studied. It is found that after 2 h of exposure in the solution at room temperature, the composition with the replacement of 10 at % titanium by magnesium showed the greatest sorption capacity. The results obtained show the promise of using magnesium-doped potassium titanate nanotubes as adsorbents of strontium ions from aqueous solutions. [ABSTRACT FROM AUTHOR]

In this study, calcium titanate (CaTiO3) doped (0, 15, 25 and 35%) polyaniline (PANI) composites in the presence of dodecylbenzene sulphonic acid (DBSA) were successfully synthesized by the means of in-situ emulsion polymerization of aniline monomer. The structural, morphological and optical characterization of as-prepared composites were determined using X-ray diffraction (XRD), field effect scanning electron microscopy, Fourier-transform infrared spectroscopy, UV–vis analysis, and electronic conductivity was determined using two-point probe method. The structural analysis confirms that PANI–DBSA is amorphous, but sharp peaks present in XRD patterns in composites are of crystalline nature. The morphological study reveals efficacious integration of CaTiO3 particles into the PANI–DBSA matrix. Further, the integration of CaTiO3 remarkably reduced the optical bandgap (2.7–2.2 eV) by making composites with PANI–DBSA. Room temperature alternating current conductivity was found to obey universal power law and correlated barrier hopping was found most appropriate model to describe the sample's charge transport mechanism. With the increasing wt% of CaTiO3, the dielectric permittivity and loss both varied according to the interfacial polarization law of Maxwell–Wagner. Moreover, the I–V graphs showed augmented electrical conductivity of composites with an increase in CaTiO3 particle content than that of pure PANI–DBSA. This is a simple way by which PANI–DBSA/CaTiO3 composites having low optical bandgap, high electrical conductivity and permittivity may be fabricated for a widespread technological application. [ABSTRACT FROM AUTHOR]

This paper considers the effect of adding niobium oxide (Nb2O5) to ferroelectric ceramics based on calcium titanate (CaTiO3), and establishes a connection between the observed alterations in strength and dielectric properties and the variation in the Nb2O5 dopant concentration in the ceramics' composition. The method of mechanochemical solid-phase synthesis was used as the main method for obtaining the ceramics, followed by thermal sintering under specified conditions in order to form a stable phase composition of the ceramics, and to initialize phase transformations in the composition. Based on the assessment of the phase composition of the resulting ceramics, it was determined that a growth in the Nb2O5 dopant concentration beyond 0.10 mol results in the formation of an orthorhombic-phase CaNb2O4 of the Pbcm(57) spatial system, the weight contribution of which grows. A growth in the Nb2O5 additive concentration results in the formation of two-phase ceramics, the formation of which allows for an enhancement in the mechanical strength of ceramics and resistance to external influences. During the study of the dependence of the strength properties on the dopant concentration alteration, a three-stage change in hardness and crack resistance was established, regarding both structural ordering and phase transformations. The measurement of dielectric characteristics showed the direct dependence of dielectric losses and the dielectric constant on the phase composition of ceramics. [ABSTRACT FROM AUTHOR]