Influence Of Synthesis Temperature Research Articles

Synthesis and photocatalytic activity of BiOI particles: An efficient visible-light-driven degradation of organic pollutants in aqueous environments

Bismuth oxyiodide (BiOI) particles were successfully fabricated through solvothermal activation using bismuth (III) nitrate pentahydrate and potassium iodide as precursors. The photocatalytic activities of BiOI were investigated under the influence of synthesis temperature (120–200 °C) with a fixed duration of 12 h. The physical-chemical properties of the samples were systematically investigated using X-ray diffraction, scanning electron microscopy, N2-sorption isotherm techniques, and pH of the point of zero charge (pHpzc). The prepared BiOI exhibited a single phase with a non-uniform 2D morphology with different sizes, an average crystallite size of 30 nm, and a BET surface area of 20.71 m²g−1. The zero-point charge was determined to be 7.7. The photocatalytic performance under simulated solar light irradiation was investigated by examining the effects of dye initial concentration, catalyst dose, and dye pH. Remarkably, BiOI synthesized at 160 °C demonstrated an impressive 85% removal efficiency of 10 ppm MO (methyl orange) at normal pH levels (pH 6.8) within 120 min under visible light irradiation, along with the highest rate constant of 0.01418 min−1. The quenching effects of different scavengers indicate the significant role of reactive O2•– and a minor role of hVB+ and •OHads in the photocatalytic process. These findings underscore the potential of BiOI particles as efficient photocatalysts for environmental applications, particularly in the degradation of organic pollutants in water using solar light irradiation.

The influence of synthesis temperature on a polyurethane carrier used for the transfer of 2’-deoxycytidylic acid

The influence of synthesis temperature on a polyurethane carrier used for the transfer of 2’-deoxycytidylic acid

Optimization of growth conditions to obtain highly anisotropic FeCo nanowires prepared through magnetic-field-assisted chemical route

In this study, we synthesized one-dimensional α-FeCo nanowires using the magnetic-field-assisted hydrazine reduction method. The amount of hydrazine, NaOH, synthesis temperature and strength of the magnetic field were optimized to obtain high aspect ratio nanowires with good quality. Two samples, obtained at 90 °C (S12) and 60 °C (S34) with improved morphologies and aspect ratios, while keeping the other optimized conditions (Hydrazine - 1 mL; NaOH - 1.5 g and strength of the magnetic field - 4000 Gauss (G)) same, were characterized using various techniques viz. X-ray diffraction (XRD), High-resolution transmission electron microscopy (HR-TEM), selected area electron diffraction (SAED), X-ray photoemission spectroscopy (XPS) and dc-magnetization to investigate structural, electronic structural and magnetic properties. Both the samples revealed single-phase α-FeCo formation with body centered cubic (BCC) geometry with space group: Im-3m indicating decrease in the lattice parameter and crystallite dimensions at 60 °C (S34). The influence of synthesis temperature was notably observed on the magnetic properties as well. The saturation magnetization was found to be enhanced from 233 emu/g for S12 to 247 emu/g for S34 along with the enhancement in coercivity. The effective magnetic anisotropy also enhanced to be 2.3× 106 erg/cm3 in S34. In brief, the improvement in aspect ratio and morphology of the wires resulted in the enhancement of saturation magnetization and effective magnetic anisotropy. The enhanced value of magnetocrystalline anisotropy and shape magnetic anisotropy is attributable to the external magnetic field applied during growth and curling of spins due to the reduced diameter of the wires.

Green synthesis of MgAlON refractories with high strength and excellent slag corrosion resistance

The direct utilization of magnesite to synthesize magnesia-based refractories is a promising approach that not only shortens the mineral processing procedures, but also yields industrial products with high added value. In this work, we attempted to prepare MgAlON refractories with magnesite through a feasible solid-state reaction in a carbon-embedded atmosphere. Afterward, the influence of synthesis temperature and magnesite addition ratio on sintering and mechanical performance of as-synthesized MgAlON refractories was systematically investigated. Besides mechanical performance, the possible oxidation and slag corrosion mechanism of as-sintered MgAlON refractories was proposed. The results indicated that as-sintered refractories featured apparent porosity of 12.98%–39.29%, bulk density of 1.54–2.95 g cm−3, and cold compressive strength of 41.58–221.87 MPa. Additionally, it was found that the high magnesite content accelerated the sintering and densification process through the volume expansion effect. The slag resistance test results showed that the surface of the reacted refractory had a double-layer structure, namely the reacted slag layer and penetrated layer, indicating the slag corrosion process followed the mutual diffusion mechanism. Consequently, this work offers insight into the slag corrosion mechanism, paving the way for the cost-effective and facile synthesis of high-value MgAlON refractories from magnesite.

Influence of synthesis temperature on oxygen exchange behavior of electrode material PrBaFe2O6−δ

PrBaFe2O6−δ attracts attention as a promising material for electrode development for solid oxide fuel cells. A comparative study of the structure, oxygen non-stoichiometry, and high-temperature defect chemistry in PrBaFe2O6−δ prepared at 1000 °C, hereinafter referred to as LTS (low temperature synthesis) and at 1350 °C, hereinafter referred to as HTS, was carried out. Experimental data were obtained by X-ray and electron diffraction, thermogravimetry, and coulometric titration. The onset temperature of oxygen exchange with the gas phase was found to be 278 °C and 484 °C for the LTS and HTS oxides, respectively. The revealed advantage of the LTS oxide is argued to be conditioned by the structural features. Although X-ray diffraction identified the structure of both oxides as cubic perovskite with Pm3¯m space group, electron diffraction found in the LTS oxide the incomplete formation of an ordered superstructure with a Cmmm space group, in contrast to only the short-range ordering in the HTS oxide. The modeling of defect chemistry at 750–950°С indicates a uniform distribution of oxygen ions over the available anion positions with close thermodynamic parameters of the defect formation reactions for both oxides. These results, however, can reflect only a peculiarity of the LTS oxide state with disordered anion sublattice at high temperature and does not mean unambiguous independence of oxygen exchange behavior on thermodynamic parameters of the oxidation reaction.

Influence of Synthesis Temperature on the Structural, Morphological and Optical Properties of MoO3 Nanorods.

Molybdenum trioxide nanomaterials have attained notable attention in the recent past and are used in various optoelectronic and biomedical applications. Here blue and purple blue light emitting MoO3 nanophosphors were synthesized using the simple hydrothermal method at three different temperatures 100ºC, 150°C, and 200°C. Structural characterization using XRD along with Raman spectroscopy confirms the formation of a highly stable orthorhombic phase. Micro strain effects have been analyzed by employing the Williamson-Hall method using a uniform deformation model. Nanorod like morphology was obtained from FESEM. Optical analysis, using Tauc plot shows a decreasing trend in bandgap value with increasing temperature. Emission peaks in the photoluminescence spectrum are associated with the transition between the sub-bands of the Mo5+ defect state. From CIE coordinates it is confirmed that the characteristic light from the samples is blue and purple-blue. Being an excellent blue and purple blue light emitting phosphor, MoO3 is a suitable material for future LED and fluorescence imaging applications.

Influence of synthesis temperature on morphology and electrochemical performance of NiCo hydroxides for supercapacitor applications

Influence of synthesis temperature on morphology and electrochemical performance of NiCo hydroxides for supercapacitor applications

Influence of synthesis temperature and atmosphere on Te4+ ion formation in lithium tellurite glass

In this research, the influence of synthesis process under Te4+ ion formation in lithium tellurite glass was investigated based in their optical and structural characteristics. The same 80TeO2 + 20Li2O nominal composition (in mol%) was used to prepare glasses with different synthesis temperatures (Ts = 600, 700, 750, 800 and 850 °C) and atmospheres (room, oxygen and argon). The study was based in the investigation of the UV–Vis absorption spectroscopy, Raman spectroscopy, photoluminescence (PL) and photoluminescence excitation (PLE) spectroscopies. The linear refractive index was measured in function of the wavelength ranging all the visible region. The results indicate that Te4+ concentration into the glass is strongly dependent on both synthesis temperature and atmosphere. A more intense emission is observed in glasses prepared in oxygen atmosphere and in the 750–800 °C temperature range.

Synthesis and Characteristics of Sr3La(PO4)3:Eu3+ Phosphor with Luminescence in NIR Biological Window

The Sr3La(PO4)3:Eu3+ (SLP:Eu3+) phosphor was prepared with the coprecipitation method, which emited red visible-light along with a near-infrared (NIR) luminescence in the biological window region. The influence of synthesis temperature and Eu3+ doping concentration on the characteristics of the phosphor was discussed. The optimal crystallinity was obtained when the phosphor was doped with 0.7 mol% of Eu3+ and annealed at 1200 °C for 2 h. The particle size was approximately 1 μm. As compared with the SLP:0.01 Eu3+, the photoluminescence intensity of the SLP:0.07 Eu3+ increased by 4.95-fold at wavelength of 615 nm and 3.97- fold at 705 nm. The red SLP:Eu3+ phosphor with a high NIR emission is a potential candidate material for bio-image and bio-sensor applications.

Effect of synthesis temperature on catalytic activity and coke resistance of Ni/bio-char during CO2 reforming of tar

Understanding how the synthesis parameters affect nickel particle distribution is critical to the synthesis of Ni/bio-char with excellent catalytic performance. In this work, the influence of synthesis temperature on catalytic activity and coke resistance of Ni/bio-char during CO2 reforming of tar was explored. With the increase of synthesis temperature from 200 °C to 250 °C, the dispersion of nickel precursor into bio-char was promoted, resulting in an increase in crystallite size of metallic nickel particle from 51.98 nm to 62.45 nm. Besides, parts of the metallic nickel particles were oxidized to nickel oxides, providing more lattice oxygen to oxidize the coke deposited on the catalyst. However, further increasing the synthesis temperature to 300 °C would aggravate the oxidation of active nickel particles. The increase in crystallite size of nickel oxide particle from 23.25 nm to 43.38 nm could block the pore structure and hinder the access of reactants, resulting in a drop in the tar conversion rate from 40-51% to 13–27%.

Effect of thermal treatment conditions on the solid-state synthesis of barium zirconate from barium carbonate and monoclinic zirconia

In the present work the solid-state synthesis of phase-pure barium zirconate (BaZrO3) using barium carbonate and monoclinic zirconia as powder raw materials is investigated. Due to the high evaporation tendency of BaO, special attention is paid to the thermogravimetric behaviour of stoichiometric mixtures of BaCO3 and ZrO2, namely without sintering aids. DSC/TG measurements of the powder mixtures were conducted to assess the synthesis reaction using heating rates of 1, 3 and 10 K min−1. In addition to the investigations of the thermogravimetric behaviour in dependence of different heating rates, the influence of synthesis temperature and ceramic carrier grains was examined on pressed specimens of 50 mm in diameter. Moreover, the influence of three different partial pressure relations resulting from the decarbonisation reaction and the assumed BaO evaporation was investigated. It was found that a synthesis temperature of 1200 °C and a heating rate of 1 K min−1 resulted in the least pronounced mass loss and mass loss rate, respectively. XRD analyses revealed phase-purity for specimens of assumed low BaO evaporation. Thus, optimum thermal treatment conditions were identified for the BaZrO3 synthesis that can be applied to the production of phase-pure material for e.g. the refractory industry.

Influence of Synthesis Temperature on the Phases Developed and Optical Properties of Manganese Sulfide and Zinc Sulfide

AbstractNano MnS and ZnS samples are prepared through a simple thermolysis procedure. The effect of synthesis temperature on the different phases formed and their percentages, and on the lattice parameters and crystallite size of MnS and ZnS is examined using Rietveld analysis for X‐ray diffraction patterns. The minimum synthesis temperature at which MnS can be formed by the present simple procedure is 250 °C, while ZnS can be prepared at a lower temperature of 200 °C. For manganese sulfide, traces of Mn3O4 phase appear at 300 °C and increase with temperature, while ZnS resists oxidation until 500 °C; pure ZnO forms at 700 °C. The MnS and ZnS samples, obtained at all temperatures, are found to be biphasic; cubic and hexagonal. The nano nature of the samples and the particle morphology are investigated by high‐resolution transmission electron microscopy. Fourier‐transform infrared spectroscopy is applied to follow the characteristic vibration bands in both systems. The values of the different energy gaps depend on the crystallite size, phases’ percentages, and the preparation temperature. The photoluminescence intensity and the emitted colors from MnS and ZnS depend on the synthesis temperature.

Regularities of structure and phase formation at the synthesis of AlN‒Al<sub>2</sub>O <sub>3</sub>‒Y <sub>2</sub>O <sub>3</sub>compositions in the combustion mode

The results of studies on the synthesis of AlN‒Al2O3‒Y2O3 compositions in the combustion mode in an industrial reactor are presented. The influence of synthesis temperature on the formation of microstructure, phase composition of compositions and oxygen content of impurities dissolved in the crystal lattice of aluminum nitride was studied. The optimal synthesis temperature is determined. Experimental batches of composite powders were produced for the production of dielectric ceramics with high thermal conductivity.

The influence of synthesis temperature on the HT-LiCoO2 crystallographic properties

Grande parte do sucesso das baterias de íon-lítio à base de cobalto se deve à fácil síntese do HT-LiCoO2 por rotas sol-gel. Muitas rotas sol-gel reduziram a temperatura de síntese de 900 °C - para rotas de estado sólido - para 600 °C. No entanto, para se obter o composto HT-LCO por uma via química a temperaturas de calcinação moderadas, a taxa de aquecimento no estágio inicial da síntese deve ser alta. No entanto, em altas taxas de aquecimento, uma alta concentração de energia se desenvolve devido à combustão do agente quelante, causando uma grande e indesejável expansão volumétrica. Portanto, como forma de minimizar os efeitos da expansão volumétrica, a taxa de aquecimento na síntese foi investigada. Os resultados da difração de raios X mostraram que, usando uma baixa taxa de aquecimento, a formação da fase HT-LCO exige que mais do que a energia disponível a 600 oC para ser pura e se cristalize no grupo espacial desejado. No entanto, para a temperatura de calcinação de 800 °C, apenas 20 minutos foram suficientes para sintetizar uma fase HT-LCO cristalográfica com alto ordenamento. O tempo de síntese reduzido está possivelmente associado a uma alta homogeneização dos íons metálicos, uma vez que a expansão do gel é radicalmente reduzida. O LCO sintetizado a 800 °C por apenas 20 min mostrou capacidade de carga eletroquímica de cerca de 140 mAh g-1. Conclui-se que, controlando a cinética durante a etapa de aquecimento, na fase inicial da síntese, o HT-LCO é obtido com alto ordenamento cristalográfico, embora o tempo de síntese seja reduzido, possibilitando um processo de síntese economicamente mais atraente.

Facile synthesis of LiVO3 and its electrochemical behavior in rechargeable lithium batteries

Lithium vanadate, LiVO3, has been successfully synthesized by a soft chemistry route with subsequent calcinations. The influence of synthesis temperature on the structure properties including lattice parameters and crystallite size were investigated by X-ray powder diffraction. The LiVO3 compound fabricated at 350 °C has the smallest particles with diameters ranging from 500 nm to 1 μm, and possesses the best performance including high discharge capacity, good rate capability and cyclic stability as cathode materials for lithium batteries. Highly stable specific capacities of 257, 233, 203.8, 173.7 and 141.9 mA h g−1 can be achieved at current densities of 100, 200, 400, 800 and 1500 mA g−1, respectively. The phase transition of the discharged electrode has been evaluated by the ex-situ XRD techniques. Electrochemical impedance spectra (EIS) measurements were carried out to determine the influence of phase transition on the lithium diffusion coefficients.

The Influence of Synthesis Temperature on the Phase Composition and Structure of Ternary Compounds Produced from TiH2–Si–C Powder Mixtures

The paper examines the formation of phases and structure in ternary compounds produced by thermal synthesis from the TiH2–Si–C powder mixture. The alloys were thermally synthesized in vacuum at 1150, 1300, and 1400°C. According to X-ray diffraction and structural analysis, titanium carbide is the major phase in the alloy synthesized at 1150°C. The alloy also contains a Ti5Si3 silicide phase and an insignificant amount of free carbon. When synthesis temperature increases to 1300°C, the titanium carbide content decreases and a Ti5Si4 silicide phase and ternary Ti3SiC2 compound show up in the alloy. When synthesis temperature increases further to 1400°C, the alloy mainly consists of laminar ternary Ti3SiC2 grains and an insignificant amount of titanium carbide and Ti5Si4 intermetallide. An increase in the synthesis temperature from 1150 to 1400°C leads to a significant growth of grains representing the main alloy components.

New approaches in lowering the gas-phase synthesis temperature of TiO2 nanoparticles by H2O-assisted atmospheric pressure CVS process

H2O-assisted atmospheric pressure chemical vapor synthesis is a modern economical process for the gas-phase synthesis of TiO2 nanoparticles. In the present work, the influence of synthesis temperatures (100–800°C) on the phase structure, nanoparticle size, morphology, and agglomeration is investigated by transmission electron microscopy, selected area electron diffraction, X-ray diffraction, thermogravimetry, and differential thermal analysis. Down to 400°C, crystalline TiO2 nanoparticles are synthesized and at 200°C amorphous nanoparticles are formed. Therefore, a decrease in minimum synthesis temperature by more than 500°C is achieved. In addition, the paper investigates the hypothesis that the high heat capacity of the H2O particles is responsible for the achieved decrease in synthesis temperature and for the dramatic decrease in size, coalescence, coagulation, and agglomeration of the nanoparticles. It is shown that the nanoparticles size is considerably higher for nanoparticles produced with gas-phase H2O particles in comparison to those produced with liquid-phase H2O particles, (average size 41 and 13nm, respectively), because of the lower heat capacity of gas-phase H2O particles, thus confirming the hypothesis.

Influence of synthesis temperature on structural and magnetic properties of magnetoferritin

The variation of synthesis temperature made it possible to produce artificial ferritins possessing different structural and magnetic properties, size distribution, and colloidal stability. The effect of synthesis temperature on the core structure and stability of protein shell was investigated using small-angle neutron scattering, small-angle X-ray scattering, SQUID magnetometry, dynamic light scattering, and zeta potential measurements. The optimal temperature was established for the synthesis of artificial ferritin suitable for biomedical imaging applications at ∼60 °C, which is close to the protein denaturation temperature.

Influence of synthesis temperature on cobalt metal-organic framework (Co-MOF) formation and its electrochemical performance towards supercapacitor electrodes

We have synthesized cobalt metal-organic framework (Co-MOF) at different temperatures through solvothermal route as metal-organic frameworks which can be used for supercapacitors. The effect of synthesizing temperature on Co-MOF’s structure and porous behavior were analyzed with various characterization techniques like X-ray diffraction, Brunauer-Emmett-Teller surface analyzer, scanning electron microscope, and transmission electron microscope. The charge storage performance of the as-prepared Co-MOF’s was carried out in 3 M KOH. The results proved the excellent redox behavior of Co-MOFs, and a maximum specific capacitance of 952.5 F g−1 was obtained for Co-MOF/150 (synthesized at 150 °C) at a current density of 0.25 A g−1. The higher specific surface area and micropore of Co-MOF/150 significantly heightened the electrolyte ion transport during the electrochemical performance.

Facile synthesis of Tungsten Phosphide/Ketjen Black Hybrid Electrocatalyst for Hydrogen Production

Hydrogen is considered a clean and sustainable alternative energy source in future, and transition metal phosphides as substitutes for Pt-based electrocatalysts for the hydrogen evolution reaction (HER) have received widespread attention. However, exploring a facile way to synthesize efficient catalysts is still a challenge. In this work, we found a simple and safe way to obtain tungsten phosphide (WP) and the influence of synthesis temperature was also investigated. Moreover, with the modification of Ketjen Black, WP/KB heterostructures were gained, which showed an excellent HER performance in both acidic and alkaline solutions with Tafel slopes of 60 mV dec−1 and 66 mV dec−1, respectively. Furthermore, a possible improvement mechanism was also discussed.