Zr Ions Research Articles

Phase and structural evolution of dysprosia stabilized zirconia ceramics under CMAS corrosion environment

In this study, 10 wt % dysprosia stabilized zirconia (10DySZ) ceramics were prepared by pressureless sintering method. The CMAS corrosion behaviors of DySZ ceramics were investigated and the corrosion mechanism was also discussed in detail. Results show that the CMAS corrosive agent can induce phase transformation of DySZ ceramic due to the stronger ability to capture Dy stabilizers than Zr ions. During the corrosion process, molten CMAS would preferentially corrode the grain boundaries and then infiltrated into the interior of DySZ ceramic, resulting in the formation of loose structure on the ceramic surface. Sandy-shaped DySZ particles were also formed in the residual CMAS layers based on dissolution and precipitation mechanism. The corrosion temperature plays a crucial role in accelerating the phase transformation and thermal-mechanical damage of DySZ ceramic. Mismatch of thermal expansion coefficient between CMAS and DySZ ceramics as well as composition and structural difference between dense layer and porous layer are all responsible to the formation of destructive cracks.

Nanostructured cauliflowers patterning in Zr doped tungsten oxide thin films grown by AACVD

The effort is made to grow the cellular segmentation patterning of undoped and Zr doped Tungsten Oxide (ZWO) coatings engineered by aerosol assisted Chemical Vapor Deposition (AACVD) onto silica glass at 400 °C. Nanostructured cauliflowers were successfully grown without using any particular template via the chemical route of AACVD for undoped and Zr doped Tungsten Oxide. The tailored coatings of nano cauliflowers were explored by employing FE-Scanning electron microscopy/Energy Dispersive X-ray spectroscopy (FE-SEM/EDX), X-ray photoelectron spectroscopy (XPS), X-ray diffractometry (XRD), Fourier transformation Infrared spectroscopy (FTIR), UV-VIS spectroscopy (UV-VIS) and four-point probe method to study surface morphological, chemical composition, optical and electrical properties systematically. Morphological features present fractal-type cauliflower patterning because of Zr incorporation. XRD spectra revealed a monoclinic (WO3) phase in undoped Tungsten Oxide with preferential orientation (0 2 0) whereas Zr doping triggered the growth of Magneli suboxide W5O14 with tetragonal (0 0 1) preferred reflection. Adding Zr dopant caused a slight expansion of lattice with a decrease in crystallite size (54–18) nm. Vibrational information exhibits shoulder at around 854.30 cm−1, attributed to O–W–O bond shifting. Undoped and Zr doped Tungsten oxide thin film signatures positioned at 446.65 cm-1, 692 cm-1, and 854.30 cm-1 are witnessed with a red and blue shift in all rest of the Zr doped thin films. The mismatch of W and Zr ions in ionic radii, electronegativity, and thermal coefficients promote stresses leading to the variation in lattice parameters, bond length, and crystallite size with stretching of IR modes attributed to the incorporation of Zr into the host lattice sites of Tungsten oxide. XPS deconvoluted peaks yield the analysis for bond energy of O1s electrons located around 505.19 eV and 510.85 eV characterized as metallic oxide of Tungsten (WO3). UV-VIS spectroscopy presented a highly absorptive nature of coatings in the spectral range between (300–900) nm with the widening of both direct (1.9–3.2) eV and indirect (1.9–2.6) eV band gap which is of absolute interest for both fundamental and applied aspects. Transport properties unveiled the decrease of electrical resistivity of order from 106 Ω-cm (undoped) to 105 Ω-cm (Zr doped), attributed to grown high angle nanoparticles boundaries of tungsten oxide contribute to governing of nano cauliflowers and, as a result, the volume of the grain boundaries increases. The interplay between crystalline quality, tuned architecture, and oxygen vacancies can contribute to the understanding of morphological, optical, and transport properties.

Reversible Solid Oxide Cells: Cycling and Long-Term Durability of Air Electrodes

Introduction Reversible solid oxide cell (r-SOC) enables both power generation and electrolysis, when the cell can be operated as a solid oxide fuel cell (SOFC) and as a solid oxide electrolysis cell (SOEC). Many studies are being conducted to improve their performance and durability (1,2).Lanthanum strontium cobalt ferrite (LSCF) is an air electrode material with a perovskite-type crystal structure which exhibits high electronic and ionic conductivity, oxygen diffusivity, and electrocatalytic activity (3). However, performance and durability of the cells with Sr-containing oxide air electrodes have to be carefully analyzed, as Sr ions tend to easily diffuse during sintering and in long-term operation, reacting with Zr ions from the solid electrolyte to form a highly resistance reaction layer such as SrZrO3 (4-6). While the performance and durability of LSCF-based air electrodes and the Sr diffusion in SOFC operation have been studied, there are still limited number of studies on the SOEC operation, and especially on the r-SOC operation. The diffusion of constituent ions such as Co and Fe may not be negligible in SOCs.Here in this study, we fabricate YSZ electrolyte-supported r-SOCs and conduct durability studies in both SOFC and SOEC modes. STEM-EDS observation of the air electrode materials is also made to investigate the durability and diffusion of various elements in the LSCF-based air electrode of r-SOCs. Experimental R-SOCs with yttria stabilized zirconia electrolytes (YSZ, 200 µm thick) were prepared. Ni-GDC co-impregnated fuel electrode was prepared, where a mixture of La0.1Sr0.9TiO3 (LST) and Gd0.1Ce0.9O2 (GDC) at a volume ratio of 50:50 was used as the porous electrode backbone, onto which Ni-containing solution of 1 µL was impregnated for Ni loading of 0.167 mg cm-2 (7). Gd0.1Ce0.9O2 (GDC) buffer layer was prepared between the electrolyte and the air electrode to prevent elemental diffusion (8). La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) was used for the air electrode. In addition, a Pt reference electrode was deposited onto the electrolyte on the fuel electrode side. The voltage measurement terminals of the electrochemical measurement setup were connected between the reference electrode and the air electrode to evaluate the air electrode potential. 50%-humidified hydrogen (100 ml min-1) was supplied to the fuel electrode, and air (150 ml min-1) was supplied to the air electrode. Negative current density means the value in the SOEC mode, while positive current density in the SOFC mode. Results and discussion As shown in Fig. 2 describing one cycle, current density was varied at 800°C for the 1000-cycle durability tests in the r-SOC operation. The range of current density was between -0.2 A cm-2 and 0.2 A cm-2. The air electrode potential at different current densities and the electrode impedance in every 100 cycles were measured. For the 1000-hour electrolysis durability test in the SOEC mode, current density of -0.2 A cm-2 was applied for 1000 hours at 800°C. The air electrode potential and the impedance in every 100 hours were measured (9). It has been found that a gradual degradation of the r-SOCs associated with an increase in air electrode potential in the SOEC mode and a decrease in the potential in the SOFC mode could be distinguished. However, such degradation tended to be stabilized with the number of cycles.STEM-EDS observations were performed to analyze the elemental distribution around the air electrode and the electrolyte in the cell. It was found that such elemental diffusion could occur during sintering and durability experiments.AcknowledgmentsA part of this study was supported by “Research and Development Program for Promoting Innovative Clean Energy Technologies Through International Collaboration” of the New Energy and Industrial Technology Development Organization (NEDO) (Project No. JPNP20005). Collaborative support by Prof. H. L. Tuller, and Prof. B. Yildiz at Massachusetts Institute of Technology (MIT) for their continuous support is gratefully acknowledged. Figure 1

Self-assembly of molecular beacons through metal ion coordination for fluorescence imaging of miRNA in living cells.

Fluorescence nanosensors based on functional nucleic acids have been explored as a powerful sensing platform for disease-relevant miRNAs. This work developed a new hybrid nanosensor (Zr-B) through coordination-driven self-assembly of Zr ions and beacons. The prepared nanosensor exhibited high loading efficiency of beacons and could achieve sensitive and specific detection for miRNAs. The hybrid nanosensor could transfer beacons into living cells efficiently and maintain high stability and biocompatibility in the biological environment, achieving effective miRNA fluorescence imaging in living cells. Therefore, the resultant nanosensor holds potential for applications in disease diagnostics.

Enhancing the Photocatalytic Activity of Zirconium-Based Metal-Organic Frameworks Through the Formation of Mixed-Valence Centers.

Despite the desirability of metal-organic frameworks (MOFs) as heterogeneous photocatalysts, current strategies available to enhance the performance of MOF photocatalysts are complicated and expensive. Herein, a simple strategy is presented for improving the activity of MOF photocatalysts by regulating the atomic interface structure of the metal active sites on the MOF. In this study, MOF (PCN-222) is hybridized with cellulose acetate (CA@PCN-222) through an optimized atomic interface strategy, which lowers the average valence state of Zr ions. The electronic metal-support interaction mechanism of CA@PCN-222 is revealed by evaluating the photocatalytic CO2 reduction reaction (CO2 RR). The experimental results suggested that the electron migration efficiency at the atomic interface of the MOFs strongly coupled with cellulose is significantly improved. In particular, the CO2 RR to formate activity of CA@PCN-222 photocatalyst greatly increased from 778.2 to 2816.0µmolg-1 compared with pristine PCN-222 without cellulose acetate. The findings suggest that the strongly coupled metal-ligand moiety at the atomic interface of MOFs may play a synergistic role in heterogeneous catalysts.

Cathode Nanophosphors

High-current cathodic pulses on an aluminum electrode in solutions containing sufficiently high concentrations of Mg, Ca, Sr, Al, Sc, Y, or La nitrates in a mixture with H3BO3, HF, H3PO4, or H4P2O7 are accompanied by an intense intrinsic luminescence of a number of heavy metals, the ions of which are captured by salt nanofilms and luminescence under the action of hot electrons when are in an environment characteristic of crystal phosphors. The effect of the cathode nanophosphor (CNP) was found in more than 100 systems; photographs are presented for most of the systems. Ga, In, Tl, Ge, Sn, Pb, Mn, Cu, Ag, Cd, Ce, Tb, and Zr ions were activators. The effect of matrix composition on the spectral and kinetic characteristics of the CNP was shown on several examples; a qualitative description of the phenomenon is given, and the prospects for its application to chemical analysis are considered.

Atomic structure of ZrO2-doped Li2O–SiO2-based multi-component glasses revealed by molecular dynamics–reverse Monte Carlo modeling

Structural model of ZrO2-doped Li2O–SiO2-based multi-component glass, which is developed as a mother material for high-strength glass-ceramics, is constructed by the molecular dynamics–reverse Monte Carlo (MD–RMC) method based on anomalous X-ray and neutron scattering data. In particular, we have succeeded in extracting reliable local structural information around Zr from the MD–RMC model. It was found that a significant fraction of edge-sharing structural units was formed around Zr–O and Li–O polyhedra, resulting in a densely packed configuration of O atoms. This configuration was manifested by a very sharp principal peak in the neutron scattering data. Our model suggested that both the Zr and Li ions are incorporated in the glass as distorted ZrO6 octahedra and distorted LiO4 tetrahedra, respectively. These structural features are discussed in terms of the crystallization behavior of this material.

Synthesis, structural, morphological and optical properties of environment friendly yellow inorganic pigment Bi4Zr3O12

This study reports on the structural, morphological, microstructural, electronic and optical properties of 5 nm (annealed at 300 °C) and 8 nm (annealed at 500 °C) sized nanocrystals of yellow inorganic pigment Bi4Zr3O12 prepared by sol-gel auto-combustion technique. Increase in the annealing temperature from 300 °C to 500 °C does not led to structural phase change but results in minor shifts in the 2θ position of Bragg peaks towards the higher angle side, which is attributed to reduction in the unit cell volume due to well crystallization. Phase pure formation and well crystallization of 8 nm sized Bi4Zr3O12 pigment in the fluorite type fcc symmetry in the space group Fm3‾m (No. 225) have been revealed first time by detailed Rietveld profile refinement of the X-ray diffractogram, FTIR, SAED and HRTEM analysis. The FESEM micrographs showed micro-flower type morphology of the rod shaped nanocrystals of the Bi4Zr3O12 pigments. EDS and XPS analysis confirmed the stoichiometry of the constituent elements present in the Bi4Zr3O12 pigments. XPS analysis evaluated +3, +4 and −2 oxidation states of the Bi, Zr and oxygen ions respectively and also rule out presence of organic species in the two pigments. ESR, Fluorescence and XPS analysis affirmed formation of oxygen vacancies in the two pigments. UV–Vis–NIR optical reflectance data showed marginal increment in the optical band gap upon raising the annealing temperature but 8 nm sized Bi4Zr3O12 nanocrystals have shown greater reflectance in comparison to 5 nm sized Bi4Zr3O12 nanocrystals. The photoluminescence spectroscopic analysis and CIE coordinates along with CCT values showed that yellow Bi4Zr3O12 pigment could be useful for optical devices and yellow pigment applications.

Enhancement of CsPbBr3 Perovskite Single-Crystal Photodetector Performance via Zr Ion Implantation

All-inorganic halide perovskite single crystals have attracted significant attention in optoelectronic fields on account of their outstanding optoelectronic properties. Photodetectors (PDs) based on CsPbBr3 single crystal exhibit high responsivity (R) and external quantum efficiency (EQE) due to the direct optical band gap, large optical absorption throughout the visible spectrum range, and long-term stability. Herein, we prepared the centimeter-size CsPbBr3 perovskite single crystal and utilized Zr ion implantation to modify the photoelectric properties of single crystals. The optical band gap of the CsPbBr3 single crystal decreases from 2.24 to 2.12 eV, and the absorption intensity increases after Zr ion implantation. The R and EQE of the CsPbBr3 single crystal photodetector modified by Zr ion implantation are 1.0 A W–1 and 294%, respectively, with a light intensity of 3.8 mW cm–2 and a 5 V bias under 425 nm illumination, which are ten times larger than that of the pristine devices. Meanwhile, the first-principles calculation results show that the introduction of Zr ions decreases the band gap and that the Zr 4d orbit contributes to the conduction band minimum (CBM), which facilitates carrier transport in Zr ion implanted CsPbBr3 single crystals. The results show that Zr ion implantation is an effective strategy to improve the performance of the CsPbBr3 single-crystal-based PDs.

The Activity and Cyclic Catalysis of Synthesized Iron-Supported Zr/Ti Solid Acid Catalysts in Methyl Benzoate Compounds

The catalytic activity and cyclic catalysis of different methyl benzoates were studied by using a series of Lewis solid acid catalysts. The iron-supported zirconium/titanium solid acid catalysts were characterized using FTIR, SEM, XRD, and BET. The details of catalytic activity and cyclic catalysis verified that the catalyst catalyzed the reactions of 31 benzoic acids with different substituents and methanol. In addition, the mechanism was revealed according to the microstructure, acid strength, and specific surface area of the catalysts, and the yields of methyl benzoates by the GC-MS. Zr ions had significant effects on the catalytic activity of the catalyst. A certain proportion of Fe and Ti ions additionally enhanced the catalytic activity of the catalyst, with the catalyst-specific composition of Fe:Zr: Ti = 2:1: 1 showing optimal catalytic activity. A variety of substituents in the benzene ring, such as the electron-withdrawing group, the electron-donating group, large steric hindrance, and the position of the group on the benzene ring, had regular effects on the catalytic activity of the methyl benzoates. An increase in the catalyst activity occurred owing to the increases in the catalyst surface and the number of acid sites after the Fe ion was added. The catalytic activity remained unchanged after the facile recycling method was performed.

Synthesis of an "all-in-one" nanotherapeutic platform for triple-amplification chemodynamic therapy of osteosarcoma

High recurrence rates after surgery and unacceptable side effects of chemotherapy and radiotherapy are challenges in the treatment of osteosarcoma (OS). Therefore, the development of nanoplatforms with combined tumor inhibition efficiency and fewer side effects is a promising strategy for the treatment of OS. In this paper, a biocompatible therapeutic nanoplatform (Fe-Zr@PDA@GOx) was constructed with a simple and efficient strategy for the treatment of OS. First, as an excellent Fenton reaction reagent, iron ions in the nanoplatform can generate highly toxic hydroxyl radicals (•OH) with hydrogen peroxide (H2O2) in the tumor microenvironment and induce tumor cell death. Then, the modification of polydopamine endows the nanoplatform with photothermal responsiveness, with a photothermal conversion efficiency of 28.0%. Importantly, the conversed heat by polydopamine both promotes the release of glucose oxidase (GOx) and increases the rate of the Fenton reaction. Furthermore, GOx-mediated starvation treatment (SDT) can also provide suitable reaction conditions and sufficient H2O2 to realize the amplification of chemodynamic therapy (CDT). Finally, the doping of Zr ions can interact with Fe to form dual active centers in the Fenton reaction and further accelerate the generation of •OH. Both in vitro and in vivo experiments reveal the synergistic photothermal/CDT/SDT anti-tumor effect. Therefore, this work provides an effective strategy for the treatment of OS.

Increasing hot corrosion resistance of β-(Ni, Pt)Al coating by replacing Pt partially with Zr

The effect of Zr partially replacing Pt on the hot corrosion resistance of β-(Ni, Pt)Al coating at 900 ℃ has been studied due to the high cost of Pt. The Zr replacing Pt coatings with substitutions up to 17 at% and 24 at% show remarkably better hot corrosion resistance than pure (Ni, Pt)Al coating. Zr ions segregation at the oxide grain boundaries reduces the oxidation rate and Zr inhibits the development of Al2O3 intrusions through the fixation effect of Zr on S. However, the growth of ZrO2 particles in the oxide scale induced by over-doping leads to local scale spallation.

Preparation and properties of zirconium-doped copper calcium titanate ceramics for broadband electromagnetic spectrum conversion

In this paper, zirconium-doped CaCu3Ti4-xZrxO12 (0 ≤ x ≤ 0.3, CCTZO) ceramics were prepared by traditional solid-state reaction. The prepared CaCu3Ti4-xZrxO12 display cubic phase structure, as shown by the XRD analysis, and interplanar spacing increase, as obtained by TEM. The surface morphologies, electrical conductivity, optical properties, solar and microwave thermal conversion characteristics of the synthesized samples were investigated in detail. The experimental results indicate that both the solar absorbance and thermal emittance of the samples could be tailored by Zr ions doping. In general, the CaCu3Ti4-xZrxO12 system displays relatively high thermal radiation properties, with an optimal composition of CaCu3Ti3.9Zr0.1O12 exhibiting a solar absorbance of 0.85 and a thermal emittance of 0.75. The incorporated Zr ions enhanced the solar–thermal conversion while weakened the microwave–thermal conversion. Under simulated solar irradiation (3 W/cm2), the equilibrium temperature of CaCu3Ti3.9Zr0.1O12 could reach above 260 °C. The equilibrium temperature of CaCu3Ti4O12 could reach up to 493 °C at a frequency of 2.45 GHz over 140 s. The results demonstrate that the CCTZO ceramics have the potential to emerge as the broadband electromagnetic wave–thermal conversion materials.

Removal Effectiveness for Washing Ce(IV), U(VI), and Zr(IV) Ions from Contaminated Purex Solvent by Hydrazine Carbonate

The contaminated solvent from the Purex process is washed with alkaline detergents such as sodium carbonate, which generates a large amount of secondary wastes. Therefore, hydrazine carbonate as a salt-free reagent deserves to be studied in depth. In this study, the Ce(IV), U(VI), and Zr(IV) metal ions in organic phases containing dibutyl phosphate (HDBP) of 30% tributyl phosphate (TBP)–dodecane were washed with hydrazine carbonate. The effects of the oscillation time (1 to 15 min); temperature (25°C to 85°C); cumulative number of washes (one to four times); mass fraction of hydrazine carbonate (0.1% to 20%); volume ratio of the aqueous phase to the organic phase (0.2 to 5); HDBP concentration (0 to 0.4 M); HNO3 concentration (0.05 to 8 M); and concentration of Ce(IV), U(VI), and Zr(IV) metal ions on the removal percentages of Ce(IV), U(VI), and Zr(IV) metal ions in polluted solvents were studied. The results showed that when the organic phase containing 0.02 M HDBP was washed three times with 5% hydrazine carbonate at 25°C, the removal percentages of the Ce(IV), U(VI), and Zr(IV) ions were 96%, 98%, and 94%, respectively. Meanwhile, the retention concentrations of the three in the organic phase were 35, 28, and 78 mg/L, respectively. The increase of the mass fraction of hydrazine carbonate enhances the removal of the metal ions from the organic phase into the aqueous phase. High acid is not conducive to alkaline washing of metal ions. The increase of HDBP concentration not only promotes extraction but also increases the retention capacity of the organic phase and has the most significant effect on Zr(IV). U(VI) promotes the preferential washing of Zr(IV) while Ce(IV) increases the metal retention concentration of Zr(IV) in the organic phase.

In Situ Reactive Formation of Mixed Oxides in Additively Manufactured Cobalt Alloy.

Oxide-dispersion-strengthened (ODS) alloys have long been considered for high temperature turbine, spacecraft, and nuclear reactor components due to their high temperature strength and radiation resistance. Conventional synthesis approaches of ODS alloys involve ball milling of powders and consolidation. In this work, a process-synergistic approach is used to introduce oxide particles during laser powder bed fusion (LPBF). Chromium (III) oxide (Cr2O3) powders are blended with a cobalt-based alloy, Mar-M 509, and exposed to laser irradiation, resulting in reduction-oxidation reactions involving metal (Ta, Ti, Zr) ions from the metal matrix to form mixed oxides of increased thermodynamic stability. A microstructure analysis indicates the formation of nanoscale spherical mixed oxide particles as well as large agglomerates with internal cracks. Chemical analyses confirm the presence of Ta, Ti, and Zr in agglomerated oxides, but primarily Zr in the nanoscale oxides. Mechanical testing reveals that agglomerate particle cracking is detrimental to tensile ductility compared to the base alloy, suggesting the need for improved processing methods to break up oxide particle clusters and promote their uniform dispersion during laser exposure.

Simple Synchronous Dual-Modification Strategy with Zr4+ Doping and CeO2 Nanowelding to Stabilize Layered Ni-Rich Cathode Materials

A Ni-rich layered oxide, one promising cathode for lithium-ion batteries (LIBs), exhibits the advantages of low cost and high capacity but suffers from rapid capacity loss due to bulk structural instability and surface side reactions. Herein, a simple synchronous dual-modification strategy with Zr4+ doping and CeO2 nanowelding is proposed to address such issues. Utilizing the migration energy difference of Zr and Ce ions in layered structures, one-step high-temperature sintering of LiNi0.8Co0.1Mn0.1O2 particles with Zr and Ce nitrate distributions enables simultaneous doping of Zr ions in the bulk and CeO2 surface modification. Therein, Zr ions in the bulk occupying the Li sites can improve the Li+ diffusion rate and stabilize the crystal structure, while CeO2 on the surface provides nanowelding between the grain boundaries and resistance to electrolyte erosion. Theoretical calculations and a series of structure/composition characterizations (i.e., neutron scattering, in situ X-ray diffraction, etc.) validated the proposed strategy and its role in stabilizing the Ni-rich cathodes. The synergistic effect of Zr4+ doping and CeO2 nanowelding enables an impressive initial capacity of 187.2 mAh g–1 (2.7–4.3 V vs Li/Li+) with 86.1% retention after 200 cycles at 1 C and rate capabilities of 146.6 and 127.3 mAh g–1 at 5 and 10 C, respectively. Upon increasing the testing temperature to 60 °C, the dual-modified Ni-rich cathode exhibits an initial discharge capacity of 203.5 mAh g–1 with a good retention of 80.8% after 100 cycles at 0.5 C. The present strategy utilizing the migration energy difference of metal ions to achieve synchronous bulk doping and surface modification will offer fresh insights to stabilize layered cathode materials for LIBs, which can be widely used in other kinds of batteries with various cathode materials.

How do pH modifiers modulate the pore environment of polar-neutral bidentate ligated zirconium coordination polymers?

Amino acids are having higher chelating nature, which can be easily complexed with various metal ions. Generally, amino acids are considered to be bidentate ligands with amine and carboxylic functional groups. Among all, l-serine is the neutral polar ligand which consists of a hydroxyl functional group. The l-serine is used as an organic ligand in synthesizing Zr-based Coordination Polymers (CPs). During synthesis, Conc. HCl and NaOH are used as additional pH modifiers. The Ser-Zr CPs are synthesized with and without the additional pH modifiers. The pXRD results show that the Ser-Zr CPs possess a short-range ordered network, i.e., amorphous and having qualitatively coarse surface texture. The FTIR spectrum evidences the bonding between the Zr ion and the l-serine ligand through Zr–N bonding at 644 cm−1. The Ser-Zr CPs synthesized with Conc. HCl possesses enhanced BET surface area, average pore diameter, and total pore volume of 760 m2/g, ∼8.28 nm, and 1.563 cm3/g, respectively. Similarly, the Ser-Zr CPs synthesized with Conc. HCl has multilayer bottle-neck type mesopores. However, the thermal stability of all the Ser-Zr CPs is ∼250 °C. The formation of Ser-Zr CPs and the coordination of serine with Zr are further characterized by ICP-OES and CPMAS NMR spectroscopies. The morphology and crystallinity of the Ser-Zr CPs are studied using a high-resolution transmission electron microscope. The amorphous Ser-Zr CPs can be utilized in applications such as gas adsorption and storage, separation, purification, drug delivery, and many more.

Influence of B-site zr ion substitution on the structural, dielectric and ferroelectric properties in Bi0.5Na0.5TiO3-based lead-free ceramics

Influence of B-site zr ion substitution on the structural, dielectric and ferroelectric properties in Bi0.5Na0.5TiO3-based lead-free ceramics

Improvement in deformation degree of Zr surface-layered Bi-2223 ceramics by diffusion annealing temperature

This study investigated the effects of different annealing temperatures (650 °C ≤ T ≤ 840 °C) on the surface morphological and mechanical performance properties of Zr surface-layered Bi-2223 materials with scanning electron microscopy (SEM) images, Vickers microhardness (Hv) measurements, and semi-empirical mechanical approaches. It was observed that the ceramic compound exposed to 650 °C annealing temperature exhibited the superior performance features due to the enhancement in the deformation degree. This is because the Zr ions behaved as the nucleation centers to prevent the propagations of cracks and dislocations throughout the main matrix depending on the decrease in the degree of granularity and distributions of crystal structure problems over a wider area. Similarly, the SEM pictures indicated that the diffusion mechanism increased the random distributions of the thinner plate-like granular structures (serving as nucleation centers), leading the decrease in the coupling problems between the grains. Among the materials, the highest surface densification was observed for the compound exposed to 650 °C. Namely, surface morphological analysis showed a strong correlation between microstructure and mechanical performances. Further, the zirconium ions were found to decrease in the non-recoverable stress concentration sites, crack-initiating defects, and dislocations in the ceramic system. Accordingly, the sensitivity to the applied test load was noted to decrease dramatically. Shortly, crack growth size and velocity were observed to be more easily under control. Correspondingly, the Zr ions delayed considerably the beginning points of saturation limit (load-independent) regions for the bulk Bi-2223 superconducting materials. Additionally, the Zr ions led to the change in the mechanical characteristic behavior from typical indentation size effect to reverse indentation size effect. Lastly, the microindentation hardness measurements were semi-empirically analyzed by the different models. According to the comparison, Hays-Kendall mechanical model was noted to provide the closest parameters to the load-independent microhardness results.

Synthesis and Spectral, Thermal and Antimicrobial Investigation of Mixed Ligand Metal Complexes of N-Salicylidene Aniline and 1,10-Phenanthroline

Coordination compounds of Co(II), Cu(II), Y(III), Zr(IV) and La(III) ions were synthesized from the N-salicylidene aniline (L) derived from the condensation of aniline with salicylaldhyde and 1,10-phenanthroline (phen) as a secondary mixed ligand. L, phen and their complexes were characterized using various physiochemical methods, such as elemental analyses (CHN), Fourier-transform infrared spectroscopy (FT-IR), molar conductance (Λ), magnetic susceptibility (μeff), proton nuclear magnetic resonance (1H NMR), ultraviolet–visible spectroscopy (UV–Vis) and thermogravimetric analysis (TG/DTG). The analytical and spectroscopic data supporting the chemical formulas of the metal complexes and chelation of L and phen with the metal ions forming octahedral complexes. FT-IR spectra demonstrated that L chelated with metal ions as a bidentate ligand via the oxygen atom of the phenolic group with a band in the range 3378–3437 cm−1 and the nitrogen atom of the azomethine group at 1612 cm−1. In addition, phen chelated through two nitrogen atoms in the range 1525–1565 cm−1. The 1H NMR results confirmed the IR assumption that the ligand connected to the metal ions via the phenolic’s oxygen atom. The molar conductance measurements of the complexes revealed high values of the electrolytic nature of these complexes in the range of 90.40–125.80 S cm2 mol−1. Thermal analysis (TG/DTG) was used to differentiate between coordinated and hydrated water molecules and the thermal stability of the complexes. Finally, the anti-microbial activities of the complexes were investigated against fungi (Candida albicans), Gram-negative bacteria (Escherichia coli and Salmonella typhimurium) and Gram-positive bacteria (Staphylococcus aureus and Micrococcus sp.) using the disc diffusion method. The La(III) complex was significant against C. albicans compared with all other compounds and reference standard control.