Simple Solid-state Reaction Method Research Articles

The Impact of the Final Sintering Temperature on the Microstructure and Dielectric Properties of Ba0.75Ca0.25TiO3 Perovskite Ceramics.

Ba0.75Ca0.25TiO3 ceramics were successfully synthesized by a simple solid-state reaction method. This study examined the influence of sintering temperature on the structure, microstructure, dielectric properties and electrical behavior of the material. The XRD analysis reveals that the tetragonal phase (P4mm) is dominant in all the synthesized materials, with those sintered at T = 1400 °C and T = 1450 °C being single-phase, while others exhibit a minor orthorhombic phase (Pbnm). Higher sintering temperatures promoted better grain boundary formation and larger grain sizes. The electric permittivity increased with temperature up to T = 1400 °C, followed by a sharp decline at T = 1450 °C. Additionally, the Curie temperature decreased with increasing sintering temperature, indicating changes in phase transition characteristics. Thermal analysis showed that higher sintering temperatures led to sharper heat capacity peaks, while pyroelectric and thermally stimulated depolarization currents were maximized at T = 1400 °C due to oxygen vacancies. These findings highlight the significant impact of sintering temperature on the material's structural and functional properties.

Synthesis and Characterization of Iron–Sillenite for Application as an XRD/MRI Dual-Contrast Agent

In the present work, iron–sillenite (Bi25FeO40) was synthesized using a simple solid-state reaction method and characterized. The effects of the synthesis conditions on the phase purity of Bi2O3/Fe3O4, morphological features, and possible application as an XRD/MRI dual-contrast agent were investigated. For the synthesis, the stoichiometric amounts of Bi2O3 and Fe3O4 were mixed and subsequently milled in a planetary ball mill for 10 min with a speed of 300 rpm. The milled mixture was calcined at various temperatures (550 °C, 700 °C, 750 °C, 800 °C, and 850 °C) for 1 h in air at a heating rate of 5 °C/min. For phase identification, powder X-ray diffraction (XRD) analysis was performed and infrared (FTIR) spectra were recorded. The surface morphology of synthesized samples was studied by field-emission scanning electron microscopy (FE-SEM). For the radiopacity measurements, iron–sillenite specimens were synthesized at different temperatures and mixed with different amounts of BaSO4 and Laponite solution. It was demonstrated that iron–sillenite Bi25FeO40 possessed sufficient radiopacity and could be a potential candidate to meet the requirements of its application as an XRD/MRI dual-contrast agent.

Perovskite-structured RFeO3 (R = Tm, La) over nickel foam for robust oxygen evolution reaction

Transition metal oxides have gained significant recognition for their remarkable catalytic performance in the oxygen evolution reaction (OER). Among this group, the perovskite-structured ABO3 compounds have emerged as prospective OER electrocatalysts, particularly when selections are made for the constituents occupying the A and B sites. Here, we employed a simple solid-state reaction method to synthesize perovskite-structured RFeO3 (R = Tm, La) and subsequently loaded them on high-conductive nickel foam (NF) for OER. The results reveal that RFeO3/NF (R = Tm, La) catalysts exhibit low overpotentials of 361 mV and 357 mV, respectively, for OER at a current density of 10 mA·cm−2, indicating substantial advancements in both catalytic activity and efficiency.

Red-emitting Mn4+-doped Li2MgSn2O6 phosphors for plant growth LED lighting

In this study, a novel red-emitting Mn4+ doped Li2MgSn2O6 (Li2MgSn2O6:Mn4+) phosphors were successfully synthesized using a simple solid-state reaction method. XRD patterns indicated the replacement of Mn4+ ions with Sn4+ ions in the [SnO6] octahedrons site of the Li2MgSn2O6 lattice, and XPS spectra confirmed the Mn4+ oxidation state. Excited at 323 nm and 480 nm, the phosphors exhibited a strong red emission band peaking at 659 nm, attributed to the 2E → 4A2 transition of Mn4+ ions. Notably, the highest PL intensity was found in the Li2MgSn2O6:0.3%Mn4+ sample annealed at 1000 °C. These phosphors, with a particle size of 1.0 μm, possess a long lifetime of 0.176 ms, high activation energy of 0.335 eV, excellent color purity of 99.9%, and good internal and external quantum efficiency of 44.5% and 24.1%, respectively. Furthermore, an LED coated with Li2MgSn2O6:0.3%Mn4+ phosphor on a 365 nm NUV LED chip showed strong emission matching the absorption spectrum of the red phytochrome. Therefore, these results indicated that the synthesized Li2MgSn2O6:Mn4+ phosphors could be used as red-emitting materials for plant growth LED applications.

Utilizing rare earth titanates to improve performance of solid-state electrochromic device

Exploring new materials and synthesis recipes are required to enhance the electrochromic performance especially, when used in solid-state devices. Here, polycrystalline gadolinium titanate (Gd2TiO5 or GTO), synthesized using a simple solid-state reaction method, has been used for this purpose by combining it with polythiophene (P3HT). The electrochemical investigation of the Gd2TiO5 doped P3HT electrode has been carried out using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), which reveals the dominance of diffusion-controlled mechanism over charge storage on the electrode surface as compared to the P3HT electrode. The Gd2TiO5 doped P3HT solid-state electrochromic device shows color modulation at 515 nm and 670 nm wavelengths with a color contrast of as high as 79% and 42%, respectively, under an external bias of as low as ±1.4 V. The prepared device switches between maroon to a transparent state in less than a second under the external bias (±1.4 V) with a high coloration efficiency of 346 cm2/C. The device shows improved cycle life over 100 switching cycles at both the wavelengths, which makes it more suitable for real-life applications.

Influence of Bi doping on the structure and electromagnetic wave absorption for LaFeO3 perovskite

LaFeO3 perovskite has possessed great potential in the field of microwave absorption considering its outstanding dielectric and magnetic properties. In this work, Bi-doped LaFeO3 powders (BLFO) were prepared by a simple solid state reaction method. The results have demonstrated that the crystalline of LaFeO3 and the lattice oxygen are increased with the additionally introduced Bi. As a result, the samples could exhibit the strongest microwave absorption with the minimum reflection loss (RLmin) of −39.48 dB and the effective absorption band (EAB) of 3.63 GHz (10.28–13.91 GHz) at a filling ratio of 60 wt%. The excellent microwave absorption properties are ascribed to the enhanced conductive loss, polarization relaxation and the co-existed magnetic loss. Moreover, the optimum sample exhibits the radar cross-section values below −10 dBm2 across a wide angular range of −90° to 90° with a thickness of 2.5 mm. Therefore, this work opens up a feasible and effective way for modulating the electromagnetic properties of perovskite materials as potential microwave absorbents.

Facile preparation of a PbS:Ni nanostructure using solid state synthesis route: microstructural, dielectric, and electrical properties

In the present study, a novel PbS:Ni (10 at. %) nanostructure was synthesised via a simple solid state reaction method at 400 °C and constant pressure. X-ray diffraction analysis confirms the formation of a face-centred cubic crystalline structure. Preferential growth is observed along the (311) plane direction. The calculated crystallite size of PbS:Ni (10 at. %) from XRD analysis was found to be equal to 65 nm. Scanning electron microscopy revealed the formation of nanostructured PbS:Ni (10 at. %) materials. Its band gap of ~ 2.14 eV was determined by photoluminescence spectroscopy. Raman spectroscopy was used to confirm the structure of the material. Electrical properties were studied by I-V characteristic at ± 5 V and a temperature range from 100 K to 300 K. The lnV-lnI plot showed a non-linear behaviour of PbS:Ni (10 at. %). Impedance spectroscopy is applied at temperatures from 100 K to 300 K in a frequency range from 20 Hz to 2 MHz to observe the dielectric response of PbS:Ni (10 at. %). As obtained, ε′ ~ 26 and conductivity in the order of 10–4 S · cm–1 were obtained at all temperatures above 104 Hz. The results obtained from photoluminescence spectroscopy, I-V characteristics and impedance spectroscopy confirm that PbS:Ni (10 at. %) can be considered as a suitable material for optoelectronic applications.

Multicolor tunable luminescence and energy transfer of Tb3+/Eu3+ doped NaLaP2O7 pyrophosphate phosphors

The pyrophosphate NaLaP2O7 (NLP) samples doped with Tb3+ and Eu3+ were prepared by a simple high-temperature solid state reaction method. The XRD, SEM and spectroscopy were used for characterization. The phosphors exhibited a pure phase identified by XRD. The powders are aggregates of much smaller particles with individual sizes of about 1 μm or even smaller in diameter. The crystal structures were refined by the Rietveld method, and the unit cell parameters decreased with increasing doping concentration. The luminescence properties of the phosphors are analyzed in detail. The optimal doping concentration was determined to be 16 at.% for NLP:Tb3+ and 10 at.% for NLP:Eu3+. The color tunable luminescence from green to red was achieved by co-doping Tb3+ and Eu3+. The fluorescence dynamics fitting based on the Inokuti-Hirayama model revealed that the energy transfer mechanism is mainly contributed by the electronic dipole-dipole interaction. The energy transfer efficiency from Tb3+ to Eu3+ under 376 nm excitation is more than 50 % when the concentration of Eu3+ exceeds 10 %. Under 376 nm excitation, the emission intensity of NLP:0.16 Tb3+, 0.10Eu3+ at 423 K remains 86 % of that at room temperature, and the quantum efficiency of NLP:0.16 Tb3+, 0.10Eu3+ at room temperature is 44.29 %. The results indicate that the prepared NLP:Tb3+, Eu3+ is potential for pc-WLED applications.

High-entropy (La0.2Dy0.2Er0.2Yb0.2Y0.2)2Zr2O7 oxide, a potential thermal barrier coating material with photoluminescence property sensitive to pressure

In this work, high-entropy (La0.2Dy0.2Er0.2Yb0.2Y0.2)2Zr2O7 oxide (RZHEO-1600) has been synthesized by using a simple solid-state reaction method and investigated as a promising thermal barrier coating (TBC) material with potential optical pressure sensing application. Compared to oxide-yttria stabilized zirconium (YSZ) and single component zirconates, RZHEO-1600 exhibits excellent thermal stability at 1600 °C and a larger thermal expand coefficient 13.5 × 10−6 K−1 due to the high entropy effect. Its thermal conductivity (1.23–1.41 W m−1 K−1) and Vickers hardness (10 GPa) are lower than YSZ, while its fracture toughness (2.9 MPa m1/2) is much larger. The photoluminescence (PL) emissions of RZHEO-1600 excited by 514 nm laser are assigned to 4S3/2 → 4I15/2 and 4F9/2 → 4I15/2 transitions of Er3+ ions. The centre positions of emission peaks initially at 560 and 677 nm are sensitive to pressure, which red shift linearly with pressure coefficients of 0.178 nm/GPa (−5.650 cm−1/GPa) and 0.223 nm/GPa (−4.932 cm−1/GPa), respectively. Interestingly, the PL intensity ratios I677/I658 and I560/I547 are found to be pressure sensitive, which continuously increase during the compression. The findings of this study could serve as a new guide for the development of novel high-entropy oxide TBC materials with optical sensing applications.

Enhanced gas sensing performance to ethanol of ZnO based on Ag modification by a simple solid-state reaction method

Enhanced gas sensing performance to ethanol of ZnO based on Ag modification by a simple solid-state reaction method

Antibacterial effect and cell metabolic activity of Na2CaSi2O6, β-NaCaPO4, and β-NaCaPO4-SiO2versus hydroxyapatite

Hydroxyapatite (Ca5(PO2)3(OH)) is extensively used in diverse clinical applications because of its relatively simple synthesis protocol, low cost, and chemical similarity to the mineral component of bones and teeth. Some limitations regarding bioactivity and antibacterial activity have motivated changes in its structure and the development of alternative materials to achieve better performances as bioceramics. In this study, the antibacterial effect and cell metabolic activity of the main crystalline phases (Na2CaSi2O6, β-NaCaPO4, and β-NaCaPO4−SiO2) derived from the original 45S5 bioactive glass were evaluated and compared with those induced by a commercial powder of hydroxyapatite. Powder samples of Na2CaSi2O6, β-NaCaPO4, and β-NaCaPO4−SiO2 were synthesized by a simple and reproducible solid-state reaction method. The β-NaCaPO4−SiO2 sample exhibited the strongest effect against Pseudomonas aeruginosa, Staphylococcus aureus, and S. epidermidis, which are bacteria that normally colonize the skin but can become opportunistic pathogens when the host's resistance is low. All bacteria were eliminated within 5 min in the direct-contact test, an effect that is likely associated with changes in pH in the microenvironment generated from the partial solubilization of the material and the action of certain released ions, such as Ca2+. In vitro experiments with human cells, no sample showed cytotoxicity, and the β-NaCaPO4−SiO2 sample stood out once more inducing the most positive effect on keratinocyte and stem cell viability. Overall, the tested materials demonstrated similar or better (β-NaCaPO4−SiO2) biochemical properties than hydroxyapatite. This finding encourages us, and perhaps other research groups, to assess the bio-performance of these materials more comprehensively, aiming at the development of new products for use in tissue engineering.

Enhanced magnetic performance and in-vitro apatite-forming ability of the CoFe2 O4 doped nano-hydroxyapatite porous bioceramics.

In this research, the bioceramics system of nano-hydroxyapatite-cobalt ferrite or Ca10 (PO4)6 (OH)2 /xCoFe2 O4 (HAP/xCF), where x = 0-3 vol%, were studied. The effect of CF concentration on phase evolution, physical, microstructure, mechanical, and magnetic properties as well as the in-vitro apatite-forming ability and cell culture analysis of the HAP ceramic was investigated. XRD revealed that all HAP/xCF ceramics showed high purity of hydroxyapatite with calcium and phosphate. However, the peak of the CF phase is noted for the HAP + 3 vol% CF ceramic. The densification and mechanical properties (HV, HK, σc , and σf ) decreased with increasing the CF additive, which correlated to all HAP/xCF ceramics exhibited porous structure with increasing the percentage of porosity. The average grain size also increased with increasing the CF content. An improvement of magnetic behavior, which increasing of the Mr , Hc , and μB values, was obtained for the higher CF ceramics. In-vitro apatite-forming ability test suggested that the HAP + 3 vol% CF porous ceramic has a good apatite-forming ability. The cell culture analysis indicated that the proliferation of cells was above 97% for the HAP + 3 vol% CF porous ceramic, which means that the prepared ceramic is biocompatible. Based on the obtained results indicated that these ceramics are promising biomedical application candidates. RESEARCH HIGHLIGHTS: We fabricated the HAP/xCF ceramics by a simple solid-state reaction method. The addition of CF into HAP exhibited magnetic improvement and produced the porous ceramic, which caused good apatite-forming ability. The cell culture analysis indicated that the HAP + 3 vol% CF ceramic is biocompatible.

Novel B-site substituted KCuTa3-xNbxO9 solid solution photocatalysts with modulated band structure for visible-light-driven hydrogen evolution

Perovskite-like metal oxides (PLMOs), featuring unique structural and optical properties, exhibit great potential in photocatalytic water splitting field. However, the wide bandgap and strong carrier recombination severely suppress their photocatalytic hydrogen production activity. Thus, design and development of novel PLMO photocatalyst with extended photo-response range and enhanced photo-generated charge separation/transport efficiency remains an ongoing challenge. Herein, a series of novel B-site substituted KCuTa3-xNbxO9 solid solution photocatalysts were synthesized via a simple solid-state reaction method. With an increased content of Nb, a distinct red-shifted of the optical absorption edge of KCuTa3-xNbxO9 solid solution was observed, leading to a decreased bandgap (from 2.69 to 1.91 eV), and a positive shift of the conduction band bottom (from −0.54 to −0.49 eV vs RHE). All of the Nb-substituted KCuTa3O9 solid solutions exhibit enhanced separation efficiency of photoinduced charge carriers, which leads to increased hydrogen evolution activity, among which KCuTa0.75Nb2.25O9 exhibits the highest hydrogen evolution rate of 2.16 μmol h−1 under the visible light irradiation (λ > 420 nm), which is approximately 7-fold higher than that of the pure KCuTa3O9. This study demonstrates the potential of modulating band structure through constructing solid solutions for efficient perovskite-like metal oxides photocatalysis.

Zr-doping stabilizes spinel LiMn2O4 as a low cost long cycle life cathode for lithium ion batteries

The present commercial spinel LiMn2O4 delivers only 90 mAh/g–115 mAh/g, far lower than the theoretical specific capacity. It degrades fast caused by the Jahn–Teller effect, Mn dissolution and related side reactions that consume Li inventory. In this work, Zr doping is employed to improve the structural stability and electrochemical performance of spinel LiMn2O4. Li1.06Mn1.94–x Zr x O4 (x = 0, 0.01, 0.02, 0.04) have been successfully synthesized by a simple solid-state reaction method and evaluated as cathode for lithium ion batteries (LIB). Li1.06Mn1.92Zr0.02O4 is superior cathode material with a high capacity of 122 mAh/g at 1-C rate; long cycle stability, 98.39% retention after 100 cycles at 1-C rate, excellent high rate performance 107.1 mAh/g at 10-C rate, and high temperature performance 97.39% retention after 60 cycles. These are thought to be related to Zr doping effectively stabilizing the spinel LiMn2O4, by forming stronger Zr–O bonds in the octahedron, suppressing the Jahn–Teller effect, thus improving electrochemical performance.

Synthesis and photoluminescence characteristics of the near white emitting Dy3+ ions activated NaMBi2−x(PO4)3 [M: Ba/Ca/Ca0.5+Sr0.5/Sr/Sr0.5+Ba0.5] phosphors

The present work deals with the preparation and characterization of the NaBaBi2−x(PO4)3:xDy3+ phosphors and the impact of the host cation (M) replacement in the NaMBi1.91(PO4)3:9%Dy3+ (M: Ca/Ca0.5+Sr0.5/Sr/Sr0.5+Ba0.5/Ba) phosphors on the PXRD profile and the PL emission data. All the phosphors are prepared by simple solid state reaction method and their PXRD data confirms the single phase formation. For the NaBaBi2−x(PO4)3:9%Dy3+ phosphor, the morphology, elemental composition and the band gap estimation were carried out by FESEM-EDAX analysis and DRS studies respectively. The PL emission properties revealed that the Dy3+ occupied the low symmetry sites in the NaBaBi2(PO4)3 host lattice and the optimum emission observed for the concentration, xC = 9 mol%. The PL-lifetime of Dy3+ ions in the NaBaBi2(PO4)3 phosphors are in the range of millisecond. The temperature dependent PL studies showed that at 150 °C, the phosphor was able to retain 74.7% of its initial PL intensity value (at 27 °C) and the activation energy for thermal quenching was determined to be 0.192 eV. For λex = 349 nm, the calculated CIE color coordinates (0.339, 0.359), and the CCT value (5250 K) of the NaBaBi1.91(PO4)3:9%Dy3+ phosphor are found closer to the ideal white light. The Na(Sr0.5,Ba0.5)Bi1.91(PO4)3:9%Dy3+ phosphor has yielded the highest PL intensity, which is twice that of the NaCaBi1.91(PO4)3:9%Dy3+ phosphor. The estimated CIE color coordinates of this phosphor revealed its near white light emission property.

One-step method synthesis of cobalt-doped GeZn1.7ON1.8 particle for enhanced lithium-ion storage performance

The exploration of alternative anode materials to obtain the satisfactory lithium-ion storage performance is crucial for next-generation energy storage devices. Herein, the rational design of a completely new anode material is reported by a simple solid state reaction method, which follows an insertion-type lithiation mechanism, cobalt-doped GeZn1.7ON1.8 (Co-GeZn1.7ON1.8). The introduced cobalt increases the achievable capacity by more than 100%, originating from the additional space for the lithium-ion insertion. The Co-GeZn1.7ON1.8 particle anode delivered high capacity (861.4 mAh g−1 at 0.1 A g−1 after 200 cycles) and ultralong cycling stability (2000 cycles at 1.0 A g−1 with a maintained capacity of 435 mAh g−1), which represents outstanding comprehensive electrochemical performance. Electrochemical kinetic results confirms the existence of the pseudocapacitive and the reduced lithium-ion diffusion barrier in the Co-GeZn1.7ON1.8 particle anode. Furthermore, ex-situ XRD and XPS analyses corroborate the reversible intercalation electrochemical reaction mechanism of the Co-GeZn1.7ON1.8 anode. This study offers a new vision toward designing high-performance quaternary metallic oxynitrides-based materials for large-scale energy storage applications.

Ge-doped quaternary metallic oxynitrides GaZnON: The high-performance anode material for lithium-ion batteries

Although GaZnON, an anion material, is thought to be a good anode candidate for lithium-ion battery (LIB) owning to its superior chemical/structure stabilities and low volume expansions, the wide application of the pristine GaZnON is seriously hindered by the intrinsically tardy charge transfer kinetic. Herein, Ge cation doped GaZnON (Ge-GaZnON) is prepared by a simple solid state reaction method to study the heteroatomic doping regulated lithium-ion storage performance. Ge cation doping is confirmed by the combination of X-Ray Diffraction (XRD), Raman, and X-ray photoelectron spectroscopy (XPS), and so forth. After 200 cycles at 0.1 A g−1, the capacity of the Ge-GaZnON anode reaches up to 805.9 mAh g−1, much higher than the pristine GaZnON anode. Moreover, the reversible capacity is about 263.8 mAh g−1 after 1000 cycles. The Galvanostatic intermittent titration technique (GITT) and ex-situ electrochemical impedance spectroscopy (EIS) analyses reveal that Ge doping makes the lithiation/delithiation processes more stable with lower reaction resistance and faster charge transfer kinetic. The ex-situ analysis (XRD and XPS) reveals the good structural stability and reversibility of the Ge-GaZnON anode. This study provides a new opportunities to design the next-generation metallic oxynitrides-based materials for lithium-ion batteries.

Effect of CaF2 addition on the densification behavior and mechanical properties of resistant anorthite and its bioactivity

In the current study, anorthite ceramic (CaO, Al2O3, 2SiO2) was synthesized by a simple solid-state reaction method, using local Algerian raw materials. The effect of sintering temperature at 800, 850, 900, 950, 1000, and 1100 °C for 1h under atmosphere, and 0.5, 1.5, and 3 wt % calcium fluoride (CaF2) addition on the densification and mechanical properties of anorthite were studied. The correlation between these properties and the bioactivity of samples was investigated. The results showed that samples with 1.5 wt.% CaF2 sintered at 900 °C has the highest bulk density (2.7 g.cm-3 ), lowest apparent porosity (3%), outstanding micro-hardness (8.7 GPa), and high flexural strength (222 MPa) of anorthite. The in vitro bioactivity test was assessed by determining the changes in surface composition and morphology after immersion in a simulated body fluid (SBF) for 8 h to 21 days. The results of the bioactivity test determined the formation of hydroxyapatite (Ca5(PO4)3OH) on the sample surface after 3 days, suggesting it is a bioactive ceramic.

The Effect of Pr Doping Contents on the Structural, Microstructure and Dielectric Properties of BaBi2Nb2O9 Aurivillius Ceramics.

Aurivillius BaBi2Nb2O9 and Ba1-xPrxBi2Nb2O9 ceramics were successfully synthesized by a simple solid state reaction method. Ceramics were prepared from reactants: Nb2O5, Bi2O3, BaCO3 and Pr2O3. The microstructure, structure, chemical composition, and dielectric properties of the obtained materials were examined. Dielectric properties were investigated in a wide range of temperatures (T = 20–500 °C) and frequencies (f = 0.1 kHz–1 MHz). The obtained ceramic materials belong to the group of layered perovskites, crystallizing in a tetragonal structure with the space group I4/mmm. Modification of the barium niobate compound with praseodymium ions influenced its dielectric properties and introducing a small concentration of the dopant ion causes a slight increase in the value of electric permittivity and shifts its maximum towards higher temperatures.

Structural and Morphological Studies on Strontium Tin Phosphate SrSn(PO4)2 Nanopowder

Strontium Tin phosphate SrSn(PO4)2 nanopowder was prepared by simple Solid State Reaction method (SSR). Structural and morphological investigations of the synthesized nanopowder were characterized by Powdered X-ray diffraction study (P-XRD), Fourier transform infrared (FT-IR) Spectroscopy, Field Emission Scanning Electron Microscopy (FE-SEM) and Energy Dispersive X-ray Spectroscopy Analysis (EDS). The average crystallite size estimated from P-XRD study was around 17 nm. W-H plot method was also agreed the size of the crystallite of the prepared sample in nanoscale. FE-SEM images show agglomerates of non-uniform biscuit like nano flakes structure. Various functional groups of prepared sample exhibited phosphate related bands are confirmed by FT-IR study.