Effect Of Synthesis Temperature Research Articles

Temperature-controlled morphology and enhanced functionalities of hydrothermally synthesized SrFe2O4 nanostructures for multifaceted applications

In this study, we investigate the effect of synthesis temperature on the morphology and properties of spinel strontium ferrite (SrFe2O4) nanostructures, synthesized using a surfactant-free hydrothermal method. We demonstrate that by varying the temperature from 85 °C to 160 °C, we can control the morphology of SrFe2O4, transitioning from nanoribbons to dendritic structures, and finally to hexagonal nanoplatelets. These morphological changes correspond to significant enhancements in both magnetic and photocatalytic performance. The saturation magnetization (Ms) notably increases by up to 70 % at higher synthesis temperatures. Additionally, these nanostructures show improved efficiency in photocatalytic degradation of methylene blue dye, indicating their potential for environmental remediation. The dielectric properties of the various morphologies were also characterized, suggesting applications in electronics and energy storage. This study establishes a clear link between synthesis conditions, resulting structures, and functional performance in SrFe2O4 nanostructures, contributing to the development of advanced materials.

Fabrication and performance investigation of high entropy perovskite (Sr0.2Ba0.2Bi0.2La0.2Pr0.2)FeO3 IT-SOFC cathode material

The high-entropy oxide (HEO) concept expands the design space of solid oxide fuel cell (SOFC) cathode materials. There is great potential for the development of HEO cathode materials that has not been fully explored, and the relationship between their chemical composition, grain size, and electrochemical performance is not yet fully understood. This experimental design involved the preparation of single-phase perovskite (Sr0.2Ba0.2Bi0.2La0.2Pr0.2)FeO3 HEO SOFC cathode materials, and we systematically studied the effects of synthesis temperature and microstructure on their electrochemical performance. The results show that as the synthesis temperature increases, structural transformations from multiphase to single-phase perovskite HEO can be observed. It exhibits excellent conductivity and electrochemical performance (the minimum polarization resistance reaches 0.033 Ω∙cm2, and the maximum power density is 664 mW∙cm−2). The single-phase perovskite HEO sample exhibits higher electrochemical performances compared to those of multiphase perovskite. Furthermore, it exhibits outstanding ability to suppress Sr segregation, chemical compatibility with Ce0.8Sm0.2O1.9(SDC), and CO2 tolerance performance. The Distribution of relaxation time(DRT) analysis shows that as the synthesis temperature (1000–1150 ℃) increase, HEO single-phase formed and the oxygen atom reduction ability of the SBBLP samples was improved; and the adsorption of gas oxygen on the electrode surface is limited with porosity decreases. The work shows it is interesting and valuable to optimize the performance of SOFC cathode materials using a high entropy design.

Effect of synthesis temperature on the structural morphology of a metal–organic framework and the capacitor performance of derived cobalt–nickel layered double hydroxides

Three-dimensional interconnected nickel–cobalt layered double hydroxides (NiCo-LDHs) were prepared on nickel foam by ion exchange using a cobalt-based metal–organic framework (Co-MOF) as a template at different temperatures. The effects of the Co-MOF preparation temperature on the growth, mass, morphology, and electrochemical properties of the Co-MOF and derived NiCo-LDH samples were studied. The synthesis temperature from 30 to 50 °C gradually increased the mass of the active material and the thickness of the Co-MOF sheets grown on the nickel foam. The higher the temperature is, the larger the proportion of Co3+. β-Cobalt hydroxide (β-Co(OH)2) sheets were generated above 60 °C. The morphology and mass loading pattern of the derived flocculent layer clusters of NiCo-LDH were inherited from metal-organic frameworks (MOFs). The areal capacitance of NiCo-LDH shows an inverted U-shaped curve trend with increasing temperature. The electrode material synthesized at 50 °C had a tremendous specific capacitance of 7631 mF·cm−2 at a current density of 2 mA·cm−2. The asymmetric supercapacitor assembled with the sample and active carbon (AC) achieved an energy density of 55.0 Wh·kg−1 at a power density of 800.0 W·kg−1, demonstrating the great potential of the NiCo-LDH material for energy storage. This work presents a new strategy for designing and fabricating advanced green supercapacitor materials with large power and energy densities.

Preparation of Si3N4 powder by carbothermal reduction and nitridation of glucose and water glass

Herein, Si3N4 powders were successfully synthesized via carbothermal reduction nitridation of glucose and water glass as starting materials. The effects of synthesis temperature, glucose-to-water glass molar ratio, and Si3N4 seeding on the production were investigated. The results show that the reduction rate of silica increases with increasing temperature. The highest Si3N4 yield of 98.5 % was observed at 1450 °C after 400 min. The conversion of amorphous silica to Si3N4 was increased when the molar ratio of glucose/water glass was from 3.6 to 9.0 and is slightly affected when this ratio is greater than 9.0. Moreover, the maximum nitrogen content (N wt%) was 39.1 % when Si3N4/water glass molar ratio was 0.05. In the early stage of the reduction process, SiO2 is mainly reduced to SiC which is then converted to Si3N4.

Effect of Synthesis Temperature on Adsorbent Performance of Blending Anionic and Cationic Gels in Divalent Metal Ions Adsorption

In this study, the anionic and cationic gels were synthesized separately using copolymerization between N-isopropylacrylamide (NIPAM) and acrylic acid or chitosan through a polymerization reaction using N,N'-methylenebisacrylamide (MBAA) as a cross-linker with various monomer concentrations and synthesis temperature. The anionic and cationic gels were blended to minimize inter-intra particle association and to improve the adsorption ability. The FTIR analysis found that the synthesis of the NIPAM-co-acrylic acid and NIPAM-co-chitosan gels was successfully carried out, indicating no presence of a vinyl group in the functional group. The result showed that the ion adsorption amount of Pb2+ ions blending gels increased significantly, almost twice compared to the adsorption before blending. The adsorption amount of Pb2+ ions increased with increasing the gel synthesis temperature. The adsorption amount follows the order of Pb2+ > Fe2+ > Ni2+. The adsorption amount of Pb2+ tends to decrease with increasing sedimentation volume. The higher the synthesis temperature, the larger the porous diameter formed. These results demonstrate that blending gel of NIPAM-co-chitosan and NIPAM-co-acrylic acid is a feasible alternative for removing heavy metal ions owing to its good adsorption performance.

Effects of synthesis temperature on structures and properties of epoxidized soybean oil oligomers and starch‐based bioplastics

AbstractThe work investigated the synthesis of the oligomers with citric acid (CA) and epoxidized soybean oils (ESO) at various temperatures and the effects of the oligomers on the structures and properties of starch‐based bioplastics. CA was bonded effectively onto ESO via ring‐opening polymerization at 90°C as confirmed by the results of Fourier‐transform infrared spectroscopy, thermogravimetric analysis, and carboxylic group contents of CA‐ESO oligomers (CESO). The oligomers exhibited higher thermal stability than ESO. Regarding starch‐based bioplastics, CESO disrupted the hydrogen bonding interaction within starch molecules and formed the esterification reaction with starch. The bioplastics containing CESO exhibited remarkably higher structural homogeneity and opacity as the synthesis temperatures of CESO increased. However, the thermal properties of the bioplastics with various CESO reduced, which might be due to the decomposition of starch by CESO. The films containing CESO also exhibited lower tensile strength than the film with ESO, which might be related to the decomposition, crosslinking, and plasticization effects of CESO on starch. The bioplastics with CESO exhibited lower degradation due to a more intense interaction of CESO and starch. The study demonstrated the potential of CA as an interfacial linker of starch/ESO‐based bioplastics by adjusting the synthetic temperatures of CESO.

Effect of synthesis temperature on crystal structure, optical and magnetic properties of SmCuO3-δ ceramic phosphor

Effect of synthesis temperature on crystal structure, optical and magnetic properties of SmCuO3-δ ceramic phosphor is investigated in this work. The SmCuO3-δ ceramic has been synthesized using a sol-gel method. Rietveld analysis reveals that SmCuO3-δ ceramic crystallizes into coexisting tetragonal (I4/mmm) and monoclinic (C2/c) crystal structures. The phase fraction of the tetragonal and monoclinic phases strongly depends on the synthesis temperature. The crystallite size and particle size increase with increasing calcination temperature. The X-ray photoelectron spectroscopic spectra reveal the presence of (Cu2+, Cu3+) and (Sm2+, Sm3+) ions alongwith the oxygen vacancy centres in the phosphor. The SmCuO3-δ ceramic shows multiple magnetic phase transitions. The FTIR spectra show the presence of vibrational bands due to Cu-O and Sm-O groups. The optical band gap of the SmCuO3-δ phosphor decreases with an increase in calcination temperature and crystallite size. The photoluminescence excitation spectra show the peaks at 363, 402, 505 and 542 nm at the fixed emission wavelength of 609 nm, whereas the photoluminescence emission spectra contain peaks at 465, 515 and 609 nm at the fixed excitation wavelength of 402 nm. The photoluminescence emission intensity of the sample increases with the rising calcination temperature upto 900 °C and finally, it quenches at 1000 °C. Therefore, the SmCuO3-δ ceramic phosphor may be useful for solid state lighting, LEDs and magnetic devices.

High-Performance FAU Zeolite Membranes Derived from Nano-Seeds for Gas Separation.

In this study, high-performance FAU (NaY type) zeolite membranes were successfully synthesized using small-sized seeds of 50 nm, and their gas separation performance was systematically evaluated. Employing nano-sized NaY seeds and an ultra-dilute reaction solution with a molar composition of 80 Na2O: 1Al2O3: 19 SiO2: 5000H2O, the effects of synthesis temperature, crystallization time, and porous support (α-Al2O3 or mullite) on the formation of FAU membranes were investigated. The results illustrated that further extending the crystallization time or increasing the synthesis temperature led to the formation of a NaP impurity phase on the FAU membrane layer. The most promising FAU membrane with a thickness of 2.7 µm was synthesized on an α-Al2O3 support at 368 K for 8 h and had good reproducibility. The H2 permeance of the membrane was as high as 5.34 × 10-7 mol/(m2 s Pa), and the H2/C3H8 and H2/i-C4H10 selectivities were 183 and 315, respectively. The C3H6/C3H8 selectivity of the membrane was as high as 46, with a remarkably high C3H6 permeance of 1.35 × 10-7 mol/(m2 s Pa). The excellent separation performance of the membrane is mainly attributed to the thin, defect-free membrane layer and the relatively wide pore size (0.74 nm).

Synthesis mechanism and electrical conductivity of NbCxO1-x solid solution

Niobium oxycarbide (NbCxO1-x) is an important soluble anode utilized primarily for the electrochemical preparation of metal Nb. Based on thermodynamic analysis, this study elucidates the controllable synthesis of single-phase NbCxO1-x solid solution by the carbothermal reduction of Nb2O5. The effects of synthesis temperature, holding time, forming pressure, and carbon content on the sintering behavior of NbCxO1-x solid solution are investigated. Under the optimum conditions (1400 °C of synthesis temperature, 4 h of holding time, 100 MPa of forming pressure, and 1/7 of molar ratio of Nb2O5 to carbon black), the single-phase NbCxO1-x solid solution with the similar crystal structure to NbC and 0.440 nm of the lattice parameter is obtained. The optimum resistivity of the solid solution is only 52.10 mΩ·cm, which is two orders of magnitude lower than that before sintering. This work provides crucial raw materials for the extraction of niobium by soluble anode electrolysis, improving the efficient electrolysis of niobium.

Ethanol monitoring gas sensor based on Co2P nanomaterials by a facile hydrothermal approach

Co2P nanocomposites were successfully synthesized via a facile hydrothermal method. The microstructure, morphology and elemental composition were examined by XRD, SEM, TEM and XPS. The effects of synthesis temperature and reaction time on the sensing properties of Co2P nanocomposites were analyzed. The Co2P sensor at 200[Formula: see text]C and 3 h reaction condition exhibited optimum sensitivity toward 100 ppm ethanol. In comparison with other gases, ethanol possesses good selective characteristics at optimal operating temperature of 160[Formula: see text]C, which greatly reduce energy consumption. The above results showed that Co2P nanocomposites have the potential application as an effective sensor for ethanol detection.

Structural variation in lead(II) dithiocarbamates and effect of synthesis temperature on lead sulfide nanoparticles

Three lead(II) dithiocarbamate complexes of the type, [Pb(RR'dtc)2] (where RR'dtc = N-isoprpyl-N-(4-dimethylaminobenzyl)dithiocarbamate, N‑butyl‑N-(4-dimethylaminobenzyl)dithiocarbamate and N-(3-chlorobenzyl)-N-tetrahydrofuran-2-ylmethyl)dithiocarbamate for 1, 2 and 3, respectively) were prepared and characterized by FT-IR and NMR (1H and 13C{1H}) spectroscopic methods and X-ray structural analysis. As shown by X- ray crystallography, the coordination number of lead(II) in 1, 2 and 3 are five, six, and four, respectively. The theoretical study with density functional theory (DFT) has been utilized to optimize the structures of complexes 1–3 for HOMO-LUMO energy calculation. Various electronic properties, known as global reactive descriptors, have been calculated from HOMO-LUMO energies. Hirshfeld surface analysis indicates that the most significant contacts in packing are H…H, followed by S…H and C…H. Lead sulfide nanoparticles, PbS1 and PbS2 were prepared from complex 1 using solvothermal method under two different temperatures 60 °C and 100 °C, respectively. Morphology, composition, structure and optical properties were studied using Field emission scanning electron microscopy (FESEM), Energy- Dispersive X-ray Spectroscopy (EDS), Powder X-ray diffraction (PXRD) and UV–Vis Diffuse Reflectance Spectroscopy (UV-DRS). In this work, we demonstrate the synthesis temperature has influence on morphologies, chemical composition and structural features. Both lead sulfide nanoparticles show good photocatalytic degradation capabilities toward methylene blue dye under UV light irradiation.

Effects of synthesis temperatures on the photocatalytic activities of bismuth oxides for phenol and water oxidation under visible light

Bismuth oxides with different crystal structures possess distinct photocatalytic properties. Herein, BiO2−x and Bi4O7 were prepared by a hydrothermal process done at varied synthesis temperatures (Ts), where BiO2−x was obtained at Ts = 25–180 °C and Bi4O7 was resulted at Ts = 200–220 °C. The samples (BiO-Ts) possessed increased crystallinity and decreased visible light absorption with the increment of Ts. They showed certain activities for phenol oxidation due to the oxygen species generated by tiny room light in the dark, which were much weaker than those under visible light irradiation, and all the reaction rates decreased with the increment of Ts. For water oxidation on a photoanode, BiO2−x and Bi4O7 showed an increased and decreased activity with Ts increasing, which agrees with the corresponding charge separation efficiencies. BiO2−x possesses an improved intrinsic photocatalytic activity with increased crystallinity, but its apparent activity is determined by the organics adsorbed thereon.

Effect of synthesis temperature on the formation of nickel-copper composite nanoparticles

The influence of temperature on the process of synthesis of catalytic nanoparticles is studied. The microstructure of nanoparticles and copper to nickel ratio were investigated by transmission electron microscopy, scanning transmission electron microscopy, energy dispersive X-ray microanalysis and X-ray diffraction. It was found that even minor temperature variations led to the drastic microstructure changes in the nanoparticles.

Effect of synthesis temperature on the charge transport properties of poly(3-methylthiophene) devices

Low temperature-dependent I-V measurement was adopted to investigate an insight into the effect of synthesis temperature on the field and temperature-dependent charge transport properties of electrochemically polymerized poly(3-methylthiophene) devices. Devices having different doping levels were fabricated at two different temperatures, one at room temperature (25oC) and another at a lower temperature (5oC). The transport mechanism in the devices were studied in the temperature range 40 K to 300 K. Our studies revealed that trap controlled space charge limited conduction (TCSCLC) mechanism dominated the transport mechanism at higher temperature(T>200K) and changed to field dependent mobility model at lower temperature(T<200K). It was observed that the synthesis temperature influenced the transport parameters. Devices prepared at low temperature showed an increase in resistivity and a corresponding decrease in the charge carrier mobility compared to those prepared at high temperature. Moreover, the distribution of the trap states in the devices was also affected by the synthesis temperature, with devices fabricated at low temperature exhibiting a wider trap state distribution.

Mesoporous CoFe2O4 nanocrystals: Rapid microwave-hydrothermal synthesis and effect of synthesis temperature on properties

Cobalt ferrite (CoFe2O4) nanoparticles of the size of 7–20 nm have been easily synthesized by microwave-hydrothermal route with rapid heating at 100, 150, and 200 °C. The XRD and TEM studies establish that the pure spinel CoFe2O4 phase is obtained at all the synthesis temperatures. FTIR examination presents the bands representative of cubic CoFe2O4 phase and triton X-100 surfactant. Thermal analysis shows nominal weight loss between 25 and 1000 °C demonstrating high thermal stability of the samples. Electron microscopy examination reveals spherical morphology with the particle size increasing as the synthesis temperature increases. The EDX spectrum reveals the stoichiometric proportion to be nearly 1:2 for Co: Fe as anticipated, and the elemental mapping results show the extreme distribution of elements Co, Fe, and O. The SAED patterns show bright and distinct diffraction rings associated with the different lattice planes of cubic CoFe2O4 phase. The clear lattice fringes in HRTEM images endorse the single-crystalline nature of the nanoparticles. N2 sorption studies demonstrate mesoporous structure with specific surface area decreasing with rising synthesis temperature. These nanoparticles exhibit hysteretic magnetization at room temperature, characteristic of the ferrimagnetic material, with the room temperature saturation magnetization close to that of bulk CoFe2O4. The MS value increases, but Mr and Hc values decrease as the synthesis temperature/particle size increases. It is anticipated that the findings of this study will offer more insight into the effective use of microwave-hydrothermal synthesis to tailor the properties of CoFe2O4 nanoparticles for applications.

Activation of peroxydisulfate by MIL-88A(Fe) under visible light toward tetracycline degradation: Effect of synthesis temperature on catalytic performance

Three different MIL-88A(Fe) samples (named as MIL-88A(Fe)-65, MIL-88A(Fe)-95 and MIL-88A(Fe)-125) were synthesized by a one-step hydrothermal method at the different synthesis temperature (65 °C, 95 °C and 125 °C) on the control, and they were adopted as high-efficiency catalysts for peroxydisulfate (PDS) activation to remove tetracycline (TC) from water under visible light irradiation. Various characterization methods (including XRD, BET surface area, UV–vis DRS, PL and XPS) indicate that synthesis temperature affects the crystal facet exposure, specific surface area, band gap energy, energy band position and ≡Fe2+/≡Fe3+ ratio of as-prepared MIL-88A(Fe). Activation of PDS by MIL-88A(Fe)-95 sample showed the highest efficiency for TC degradation under visible light mainly due to the photo-generated electrons on the conduction band of MIL-88A(Fe)-95 are more likely to be captured by O2 and PDS to produce reactive oxygen species. As-synthesized MIL-88A(Fe)-95 catalyst is stable and can be efficiently reused in the process of activating PDS to degrade TC. More importantly, TC degradation efficiency in real water matrices by MIL-88A(Fe)-95/PDS oxidation system is significantly higher than that in distilled water because bicarbonate ions in selected real water bodies can promote PDS activation, suggesting good practicability of this oxidation process. Mechanism analysis verifies that 1O2, O2•−, SO4•−, and •OH participate in TC degradation. This work laid a foundation for further developing the synthesis conditions to synthesize high-performance MIL-88A(Fe) applied in PS-AOPs.

Effect of synthesis temperatures on the composition, microstructure, and microwave absorption properties of titanium nitride porous nanofibers prepared using ammonia reduction nitridation process

Effect of synthesis temperatures on the composition, microstructure, and microwave absorption properties of titanium nitride porous nanofibers prepared using ammonia reduction nitridation process

Vanadium oxide - poly(3,4-ethylenedioxythiophene) cathodes for zinc-ion batteries: effect of synthesis temperature

Vanadium oxide composites with conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) were obtained by one-step microwave-assisted hydrothermal synthesis at two different temperatures: 120 and 170 °C (denoted as V-120 and V-170, respectively). The structure and composition of the obtained samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis, X-ray photoelectron spectro­scopy (XPS), and thermogravimetric (TG) analysis. The detailed study of the electro­chemical properties of the composites as cathodes of aqueous zinc-ion battery was per­formed by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) at different current densities and by electrochemical impedance spectroscopy (EIS). It was shown that V-120 demonstrated excellent electrochemical performance in the 0.3 to 1.4 V vs. Zn/Zn2+ potential range reaching specific capacities of up to 390 mA∙h∙g−1 at 0.3 A∙g−1 with excel­lent capacity stability after 1000 charge-discharge cycles. Its functional parameters were found to be much better than those of the electrodes based on the V-170 composite obtained at a higher temperature. The effect of the synthesis temperature on the electro­chemical properties is discussed in terms of the crystallographic, compositional, and thermogravimetric properties of the samples.

Ni-CaO bifunctional catalyst for biomass catalytic pyrolysis to produce hydrogen-rich gas

In this study, high-value conversion of biomass energy was achieved by catalytic pyrolysis of corn cob in a fixed-bed reaction system to produce hydrogen-rich gas. Specifically, the effects of synthesis temperature and catalyst metal ratio of Ni-CaO bifunctional adsorption catalyst on pyrolysis gas composition, yield, and hydrogen conversion were explored. The results show that the Ni1Ca7-750 catalyst has a uniform morphology, small particulate size, large specific surface area, and good pore size distribution at a synthesis temperature of 750 °C and metal ratio of Ni/Ca = 1/7. Under the conditions of pyrolysis temperature of 600 °C and catalyst/biomass = 1/1, the syngas percentage of Ni1Ca7-750 was 85.81 vol. %, and the total pyrolysis gas yield reached 661.63 mL/gbiomass with the highest H2 concentration (68.62 vol. %), hydrogen yield (450.15 mL/gbiomass) and hydrogen conversion (65.97 wt. %). The percentage of CO2 in the pyrolysis gas was 9.11 vol. %, which was 65.4 % lower than that of the corn cob pyrolysis blank group. Thus, this study provides a specific reference for catalytic pyrolysis technology for biomass resource development and clean production.

Effect of synthesis temperature on oxygen evolution reaction of cobalt-iron layered double hydroxide

Effect of synthesis temperature on oxygen evolution reaction of cobalt-iron layered double hydroxide