Papers by Keyword: Coprecipitation

Abstract: Lanthanum (La) and Nickel (Ni)-codoped Strontium Titanate (SrTiO₃) with the formula of Sr_1-xLa_xTi_1-yNi_yO₃ has been synthesized using the coprecipitation method. This research aimed to determine the effect of nickel and lanthanum co-doping on the photocatalytic activity of SrTiO₃. Here, the Ni concentration (y) was constant at 4%, while La concentrations (x) were varied at 1% and 2%. The synthesized samples were tested via X-ray diffraction (XRD) instrument to determine the crystal structure. It exhibited that the crystallite size reduced along with increased lanthanum concentration. The photocatalytic activity of Sr_1-xLa_xTi_1-yNi_yO₃ was observed under UV and Visible light irradiation against methylene blue (MB) pollutant dyes, and the absorption was measured via a UV-Vis spectrophotometer. It revealed that all samples succeeded in degrading MB solution under the two light sources with exposure times of 1, 2, 3, and 4 hours. Further, it was found that photocatalytic activity with UV lamp irradiation resulted in a better degradation percentage than visible light irradiation. The highest degradation about 60% was achieved by Sr_0.99La_0.01Ti_0.96Ni_0.04O₃ under UV light exposure for 4 hours.

Abstract: Hematite (α-Fe₂O₃) has been synthesized from iron sand using the coprecipitation method. This study aims to determine the morphology and mineral content using SEM-EDX, crystal structure and phases formed using XRD, and magnetic properties using VSM on iron sand before and after synthesis. SEM-EDX results show that the average particle size of iron sand before and after synthesizing is 356.23nm and 12.40 µm, respectively. XRD results show that iron sand before synthesizing has multipahase including Hematite, magnetic, and ilmenite and after synthesizing produces Single Phase hematite. VSM results show that iron sand before synthesizing has saturation, remanence, and coercivity of 47.56 emu/g, 5.97emu/g, and 121.03 Oe respectively, and after synthesizing has saturation, remanence, and coercivity of 9.47 emu/g, 1.53 emu/g and 102.97 Oe respectively.

Abstract: This research investigated the Fe doping effects on the Strontium Titanate (SrTiO₃) structure to improve its photocatalytic activity. The so-called Fe-doped STO photocatalysts with a stoichiometry formula of SrTi_1-xFe_xO₃ (x = 0, 0.01, and 0.05) were successfully fabricated using the coprecipitation method. The XRD characterization confirmed the formation of STO, SrTi_0.99Fe_0.01O₃, and SrTi_0.95Fe_0.05O₃ photocatalysts and the shrinkage crystallite size due to increasing Fe content. The FTIR characterization supported the XRD results, where all samples revealed Sr-Ti-O bonds with no observed Fe-O bonds indicating the successful fabrication and doping. The photocatalytic activity was examined by the degradation of Methylene Blue (MB) dye under UV light for 1, 2, 3, 4, and 5 irradiation times, and the absorbance was determined using a Spectrophotometer instrument. All samples have successfully degraded MB dye where the %degradation linearly increased with longer irradiation times. The results further exhibited that the SrTi_0.95Fe_0.05O₃ sample had the highest %degradation at 75.3% while SrTi_0.99Fe_0.01O₃ samples achieved the highest kinetic rate at 0.2557 min^-1. All Fe-doped samples revealed better photocatalytic activity than the undoped STO, proving that Fe doping could improve the photocatalytic activity of SrTiO₃.

Abstract: Battery technology applications for energy storage are currently increasing. The most popular kind of battery in use today is the lithium-ion battery. However, lithium is limited. In fact, the need for batteries as energy storage devices grows over time. One alternative for replacing lithium-ion batteries is the sodium-ion battery because its characteristics are similar to lithium’s and it is very abundant. In this study, Na-NCM 532 has been successfully produced using a co-precipitation and solid-state method combination. The co-precipitation process, using oxalic acid as a precipitation agent and ammonia as a pH adjustor, can be used to create sodium ion-based cathode materials. It is clear from the characterization that the material has been formed and has a good structure. A hexagonally layered material structure can be seen in the XRD patterns. FTIR analysis revealed that the material was produced after the sintering process. The morphology of the substance, which has dimensions between 1 to 5 micrometers, was revealed by a SEM investigation. The EIS test results show a battery conductivity of 1.24 x 10^-4 Scm^-1_. The electrochemical performance of the Na-NCM 532 cathode sodium battery and hard carbon anode was evaluated in a type 18650 cylindrical cell. The sodium battery was tested at a voltage window of 1.5-3.7 V and a current of 0.05C produced a capacity of 40 mAhg^-1.

Abstract: Powder nanoparticles of vanadium oxide doped with titanium dioxide were successfully prepared by the chemical co-precipitation method. The sample was calcined at temperatures 150, 300, 450, and 600°C. As prepared and heat-treated samples were structurally characterized through X-ray diffraction. The crystal size, cell parameters, R-Factor, and structural properties of mixed nano oxide were investigated. The value of the goodness fit factor, R-Factor, and cell parameters were examined by Rietveld Refinement. XRD study reveals that V₂O₅ exhibits orthorhombic structure and this orthorhombic phase is fully developed at 600°C. By using XRD data crystallite size of V₂O₅ was estimated to be 33.98nm and the crystallite size of TiO₂ was estimated to be 35.04nm.

Abstract: Iron nitride is a promising material for soft magnetic composite. In the current research, iron nitride compound was produced from natural iron sand, involving coprecipitation and gas nitriding. Prior to coprecipitation, natural iron sands were separated magnetically to obtain pure Fe₃O₄. Afterward, the coprecipitation was carried out to obtain nanosized Fe₃O₄. Gas nitriding of Fe₃O₄ powders was performed at different temperatures i.e. 500 °C, 600 °C and 700 °C, under flowing NH₃ gas. Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD) are used to investigate the phases obtained after the nitriding process. XRD patterns of the resulted powder indicate that nitriding temperature at 600 °C and 700 °C can produce iron nitride material, i.e. ε-Fe₃N. While nitriding temperature of 500 °C is not able to yield iron nitrides. SEM examination reveals that the ε-Fe₃N has irregular lamellar morphology. Some impurities are still detected, in the form of Fe₃O₄, Fe₂O₃, Ti₂O₃ and TiO₂. Further works regarding the examination of the magnetic properties of the powders will be carried out.

Abstract: Synthesis of Barium M-Hexaferrite samples based on natural iron sand at Ketapang beach, Pringgabaya District, East Lombok with Mn-Ni doping (BaFe_12-xMn_xNi_xO₁₉) has been successfully carried out using the coprecipitation method. The synthesis aims to determine the characteristics of the electrical properties of the Reflection Loss sample of BaFe_12-xMn_xNi_xO₁₉ doped with Mn-Ni metal. The basic materials used in this study were natural iron sand and Barium Carbonate (BaCO₃) powder, while the doping materials used were Nickel (II) Chloride Hexahydrate (NiCl₂.6H₂O) and Manganese(II) chloride (MnCl₂) powder with a variety of mole fraction (X = 0, 2; 0 ‚4; 0‚6 and 0.8). The solvent uses distilled water, 37% hydrochloric acid (HCl), and 25% NH₄OH solution. The samples were then calcined at 25 °C, 400 °C, and 600 °C. The obtained samples show that the higher the Mn-Ni doping ion content and the calcination temperature, the smaller the resulting Reflection Loss value and the greater the absorption rate of microwaves.

Abstract: In this work it was investigated the influence of CTAB surfactant concentration on the synthesis of the compound Mn_0.75Zn_0.25Fe₂O₄ by the coprecipitation method. It was also compared the influence of hydrothermal treatment on the synthesized materials. The magnetic properties were characterized by AC susceptometry for the determination of the magnetic susceptibility and magnetic density energy. The phases, crystal structure and morphology of the nanoferrites were determined by Rietveld analysis of X-ray diffraction data. It was found the presence of two phases: Franklinite and Akaganeite and it was shown that the samples synthesized only by coprecipitation presented the tendency to increasing the crystallite sizes of the akaganeite phase and decreasing of crystallite sizes of the Franklinite phase as a function of CTAB concentration. The samples submitted to subsequent hydrothermal treatment presented a tendency to decreasing the crystallite sizes of both phases and increasing in Franklinite phase fraction, compared to the samples synthesized only by coprecipitation, suggesting that the hydrothermal treatment was effective in obtaining nanostructured materials of smaller particles.

Abstract: Bismuth ferrite (BiFeO₃) nanoparticles has been synthesized by coprecipitation method with various NaOH concentration (4, 6, 8, and 10 M) and temperature (RT, 60, 80, and 100 C). X-ray diffraction patterns showed the emergence of Bi(OH)₃ and Bi₂₅FeO₄₀ structures with crystallite size in the range of 15.1 nm to 35.6 nm. The particles sample was agglomerated. Hysterisis loop showed the linear M–H loops behaviour with no magnetization saturation in 15 kOe maximum field applied which indicates the antiferromagnetic properties. The coercivity field tends to increase by the increasing of the NaOH concentration and synthesis temperature. In addition, the annealing treatment could leads the increasing of coercivity fields while decreasing the magnetization of BFO sampel.

Abstract: A series of M-type barium ferrites with chemicals composition BaFe₁₂O₁₉ and Ba_0.7La_0.3Fe_(12-2x)(MnZn)_xO₁₉ (with x = 0.0, 0.2, 0.5) were synthesized using a chemical coprecipitation based technique. The sample was then called as BFO and BLF, BLFMZ-02 and BLFMZ-05, respectively. The structural parameters were measured by applying the full pattern fitting of Rietveld method using Fullprof program. The crystallite size was calculated using Scherrer formula and Williamson-Hall analysis method, and also confirmed by scanning electron microscope (SEM) and transmission electron microscope (TEM). The morphology of particle is composed of fine-grained aggregates with particle size distributions in the range of 70nm - 160nm. The lattice parameter (a = b and c), cell volume (V_cell) and density (ρ) of the samples were found to be changed with La, Mn and Zn substitution due to the dissimilar cationic radii of Ba²⁺ (1.49Å), La³⁺ (1.22Å), Fe³⁺ (0.64Å), Mn³⁺ (0.89Å) and Zn²⁺ (0.76Å) ions. The results of sample measurements with Vibrating Sample Magetometer (VSM) indicate that the magnetic behaviours showed that the saturation magnetization (M_s) increased gradually with the substitution of La³⁺, Mn³⁺ and Zn³⁺ ions, whereas the coercivity (H_c) was increase with addition of La³⁺ ions and then decrease significantly with the addition of Mn³⁺ and Zn²⁺ ions. The vector network analyzer (VNA) revealed that microwave absorption measured within 7 – 15 GHz frequency range indicated optimum reflection loss (RL) of-21.50dB at 10.5GHz for BLMZ-02 sample.