scholarly journals LSCF-CuO as Promising Cathode for IT SOFC

2021 ◽  
Vol 53 (4) ◽  
pp. 210411
Author(s):  
Ahmad Fuzamy Bin Mohd Abd Fatah ◽  
Mohamad Nazri Murat ◽  
Noorashrina A. Hamid
Keyword(s):  
Activation Energy ◽  
Polarization Resistance ◽  
Sol Gel ◽  
Xrd Analysis ◽  
Reduction Reaction ◽  
High Catalytic Activity ◽  
High Electrical Conductivity ◽  
Different Temperatures ◽  
Eis Analysis ◽  
Nano Size

Infiltration of copper oxide towards LSCF was done in order to enhance cathode performance due to superior properties, including high electrical conductivity and high catalytic activity for the oxygen reduction reaction. Samples were synthesized at different temperatures using the sol-gel route. The TGA results showed that LSCF achieved complete perovskite formation when calcined above 600 °C and DTA showed the formation of lattice oxygen at 550 °C. XRD analysis showed no shifted peaks and nano size levels were achieved when samples were calcined at 700 °C and 800 °C. SEM and BET showed similar analysis patterns, where the particle size increased as the calcining temperature was increased. EIS analysis further verified that the polarization resistance of the sample calcined at 700 °C was as small as 0.161 Ω, compared to 1.524 Ω with a calcination temperature of 800 °C. The activation energy of LSCF-CuO was found to be 122.2 kJ/mol, which is much lower than for conventional LSCF.

Synthesis and Characterization of Sol–Gel Prepared Silver Nanoparticles

2014 ◽  
Vol 13 (01) ◽  
pp. 1450004 ◽  
Author(s):  
Dharamvir Singh Ahlawat ◽  
Rekha Kumari ◽  
Rachna ◽  
Indu Yadav
Keyword(s):  
Silver Nanoparticles ◽  
Absorption Spectra ◽  
Annealing Temperature ◽  
Sol Gel ◽  
Xrd Analysis ◽  
Silica Matrix ◽  
Silver Clusters ◽  
Different Temperatures ◽  
Uv Visible ◽  
Average Size

Silver nanoparticles (SNPs) have been successfully prepared using sol–gel method by annealing the sample at 550°C for 30 min. The SNPs were not confirmed by X-ray diffraction (XRD) analysis when the annealing temperature was considered at 450°C. They were also not confirmed without calcination of the sample. The physical mechanism of silver clusters formation in the densified silica matrix with respect to thermal treatment has been understood. The presence of silver metal in the silica matrix was confirmed by XRD analysis and TEM image of the samples. The average size of nanoparticles dispersed in silica matrix was determined as 10.2 nm by the XRD technique. The synthesized nanocomposites were also characterized by UV-Visible spectroscopy with a peak in the absorption spectra at around 375 nm. The distribution of particle size has been reported here in the range from 8 nm to 25 nm by TEM observations of the sample prepared at 550°C. The spherically smaller size (≈10 nm) SNPs have reported the surface plasmons resonance (SPR) peak less than or near to 400 nm due to blue-shifting and effect of local refractive index. Without annealing the silica samples the absorption spectra does not show any peak around 375 nm. The FTIR spectroscopy of the three types of samples prepared at different temperatures (room temperature, 450°C and 550°C) has also been reported. This spectra have provided the identification of different chemical groups in the prepared samples. It has been predicted that the size of SNPs by XRD, UV-Visible and TEM results have agreed well with each other. It may be concluded that formation of SNPs is a function of annealing temperature.

scholarly journals Physical and chemical properties of LSCF-CuO as potential cathode for intermediate temperature solid oxide fuel cell (IT-SOFC)

2018 ◽  
Vol 14 (3) ◽  
pp. 391-396 ◽  
Author(s):  
Ahmad Fuzamy Mohd Abd Fatah ◽  
Noorashrina A. Hamid
Keyword(s):  
Large Scale ◽  
Sol Gel ◽  
Chemical Properties ◽  
Electrical Energy ◽  
Reduction Reaction ◽  
Solid Oxide ◽  
Intermediate Temperature ◽  
High Catalytic Activity ◽  
Oxide Fuel ◽  
Sem Images

Solid oxide fuel cells (SOFCs) are efficient yet environmentally benign devices that can convert chemical energy into electrical energy and heat for large scale of applications. However, higher operating temperature of this device limits the selection of proper materials to be used as electrode and electrolyte as well as sacrifices the durability. Thus, it is desirable to develop materials with superior electrochemical performance at intermediate temperature (600-900 oC) for SOFC. LaSrCoFeO3 (LSCF) doped with CuO is an attracting yet promising cathode material for IT-SOFC owing to the distinguish properties including high electrical conductivity and high catalytic activity for the oxygen reduction reaction. This work investigates the influence of the synthesis route which are sloid state route and sol-gel route towards chemical and physical properties of composite LSCF-CuO. The samples were synthesized at different temperature ranging from 600 oC to 900 oC for each route respectively. XRD results showed high purity of as-synthesized samples while in the meantime increased in crystallinity has been observed as increased in calcining temperature indicating bigger crystal size after calcined at 900 oC. SEM images showed LSCF-CuO particles tends to expand as the calcining temperature increased. Meanwhile, from TGA results it is clear to conclude that LSCF-CuO loss its weight significantly after calcined at designed temperature. 

The Preparation of BaTi4O9 by Sol-Gel Method

2016 ◽  
Vol 852 ◽  
pp. 272-277 ◽  
Author(s):  
Zhao Rong Wei ◽  
Chao Yang Shi ◽  
Bin Shen ◽  
Ming Fan ◽  
Cheng Wang
Keyword(s):  
Thermal Analysis ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Sol Gel ◽  
Xrd Analysis ◽  
Tem Analysis ◽  
Gel Method ◽  
Sol Gel Method ◽  
Different Temperatures

To promote the application of BaTi4O9 in higher-end fields, BaTi4O9 precursor has been prepared with sol-gel method (SGM. The objective products have been obtained at different temperatures and SSR-BaTi4O9 samples has been prepared for compare experiments. The studies of thermal analysis, XRD analysis, TEM analysis, specific surface area analysis, DRS analysis and FS analysis show: the crystalline of the product obtained by SGM is more purity than the product obtained by SSR; The SGM600 sample is amorphous, which can be used as an optical catalyst because of the maximum specific surface area; The SGM1000 sample is the most pure, uniform and complete in crystal.

Development of High Permeability Core Materials for Embeddable Inductors in Flexible Organic Substrates

2003 ◽  
Vol 769 ◽  
Author(s):  
C. K. Liu ◽  
P. L. Cheng ◽  
S. Y. Y. Leung ◽  
T. W. Law ◽  
D. C. C. Lam
Keyword(s):  
Low Temperature ◽  
Sol Gel ◽  
Circuit Board ◽  
Organic Substrates ◽  
Circuit Boards ◽  
High Permeability ◽  
Electrical Measurements ◽  
Different Temperatures ◽  
Spiral Inductors ◽  
Ceramic Tape

AbstractCapacitors, resistors and inductors are surface mounted components on circuit boards, which occupy up to 70% of the circuit board area. For selected applications, these passives are packaged inside green ceramic tape substrates and sintered at temperatures over 700°C in a co-fired process. These high temperature processes are incompatible with organic substrates, and low temperature processes are needed if passives are to be embedded into organic substrates. A new high permeability dual-phase Nickel Zinc Ferrite (DP NZF) core fabricated using a low temperature sol-gel route was developed for use in embedded inductors in organic substrates. Crystalline NZF powder was added to the sol-gel precursor of NZF. The solution was deposited onto the substrates as thin films and heat-treated at different temperatures. The changes in the microstructures were characterized using XRD and SEM. Results showed that addition of NZF powder induced low temperature transformation of the sol-gel NZF phase to high permeability phase at 250°C, which is approximately 350°C lower than transformation temperature for pure NZF sol gel films. Electrical measurements of DP NZF cored two-layered spiral inductors indicated that the inductance increased by three times compared to inductors without the DP NZF cores. From microstructural observations, the increase is correlated with the changes in microstructural connectivity of the powder phase.

Ordered Intermetallic Nanoparticles with High Catalytic Activity Prepared by an Electrochemically Induced Phase Transformation

2019 ◽  
Author(s):  
Du Sun ◽  
yunfei wang ◽  
Kenneth Livi ◽  
chuhong wang ◽  
ruichun luo ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Diffusion Mechanism ◽  
Reduction Reaction ◽  
Atomic Scale ◽  
High Catalytic Activity ◽  
Ambient Conditions ◽  
Magnetic Devices ◽  
Disordered Alloys ◽  
Ordered Intermetallic ◽  
Intermetallic Nanoparticles

<div> <p>The synthesis of alloys with long range atomic scale ordering (ordered intermetallics) is an emerging field of nanochemistry. Ordered intermetallic nanoparticles are useful for a wide variety of applications such as catalysis, superconductors, and magnetic devices. However, the preparation of nanostructured ordered intermetallics is challenging in comparison to disordered alloys, hindering progress in materials development. We report a process for converting colloidally synthesized ordered intermetallic PdBi<sub>2</sub> to ordered intermetallic Pd<sub>3</sub>Bi nanoparticles under ambient conditions by an electrochemically induced phase transition. The low melting point of PdBi<sub>2</sub> corresponds to low vacancy formation energies which enables the facile removal of the Bi from the surface, while simultaneously enabling interdiffusion of the constituent atoms via a vacancy diffusion mechanism under ambient conditions. The resulting phase-converted ordered intermetallic Pd<sub>3</sub>Bi exhibits 11x and 3.5x higher mass activty and high methanol tolerance for the oxygen reduction reaction compared to Pt/C and Pd/C, respectively,which is the highest reported for a Pd-based catalyst, to the best of our knowledge. These results establish a key development in the synthesis of noble metal rich ordered intermetallic phases with high catalytic activity, and sets forth guidelines for the design of ordered intermetallic compounds under ambient conditions.</p> </div>

Nickel (II) and oxovanadium (IV) complexes supported on MCM-41 mesoporous and their application in catalytic selective sulfide and thiol oxidation

2020 ◽  
Vol 23 ◽  
Author(s):  
Mohsen Nikoorazm ◽  
Maryam Khanmoradi ◽  
Masoumeh Sayadian
Keyword(s):  
Catalytic Activity ◽  
Room Temperature ◽  
Sol Gel ◽  
Reaction Times ◽  
Significant Loss ◽  
Spectral Studies ◽  
High Catalytic Activity ◽  
Catalytic Systems ◽  
Solvent Free Conditions ◽  
Mcm 41

Introduction:: MCM-41 was synthesized using the sol-gel method. Then two new transition metal complexes of Nickel (II) and Vanadium (IV), were synthesized by immobilization of adenine (6-aminopurine) into MCM-41 mesoporous. The compounds have been characterized by XRD, TGA, SEM, AAS and FT-IR spectral studies. Using these catalysts provided an efficient and enantioselective procedure for oxidation of sulfides to sulfoxides and oxidative coupling of thiols to their corresponding disulfides using hydrogen peroxide at room temperature. Materials and Methods:: To a solution of sulfide or thiol (1 mmol) and H2O2 (5 mmol), a determined amount of the catalyst was added. The reaction mixture was stirred at room temperature for the specific time under solvent free conditions. The progress of the reaction was monitored by TLC using n-hexane: acetone (8:2). Afterwards, the catalyst was removed from the reaction mixture by centrifugation and, then, washed with dichloromethane in order to give the pure products. Results:: All the products were obtained in excellent yields and short reaction times indicating the high activity of the synthesized catalysts. Besides, the catalysts can be recovered and reused for several runs without significant loss in their catalytic activity. Conclusion:: These catalytic systems furnish the products very quickly with excellent yields and VO-6AP-MCM-41 shows high catalytic activity compared to Ni-6AP-MCM-41.

scholarly journals Aqueous Sol-Gel Synthesis of Different Iron Ferrites: From 3D to 2D

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1554
Author(s):  
Justinas Januskevicius ◽  
Zivile Stankeviciute ◽  
Dalis Baltrunas ◽  
Kęstutis Mažeika ◽  
Aldona Beganskiene ◽  
...  
Keyword(s):  
Magnetic Measurements ◽  
Substrate Surface ◽  
Sol Gel ◽  
Synthesis Method ◽  
Xrd Analysis ◽  
Dip Coating ◽  
Yttrium Iron ◽  
Iron Garnet ◽  
Dip Coating Technique ◽  
Sol Gel Synthesis

In this study, an aqueous sol-gel synthesis method and subsequent dip-coating technique were applied for the preparation of yttrium iron garnet (YIG), yttrium iron perovskite (YIP), and terbium iron perovskite (TIP) bulk and thin films. The monophasic highly crystalline different iron ferrite powders have been synthesized using this simple aqueous sol-gel process displaying the suitability of the method. In the next step, the same sol-gel solution was used for the fabrication of coatings on monocrystalline silicon (100) using a dip-coating procedure. This resulted, likely due to substrate surface influence, in all coatings having mixed phases of both garnet and perovskite. Thermogravimetric (TG) analysis of the precursor gels was carried out. All the samples were investigated by X-ray powder diffraction (XRD) analysis. The coatings were also investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM) and Mössbauer spectroscopy. Magnetic measurements were also carried out.

Reversal of triboelectric charges on sol–gel oxide films annealed at different temperatures

2021 ◽  
Vol 118 (24) ◽  
pp. 243902
Author(s):  
Yongqiao Zhu ◽  
Shiquan Lin ◽  
Wenchao Gao ◽  
Miao Zhang ◽  
Dawei Li ◽  
...  
Keyword(s):  
Sol Gel ◽  
Oxide Films ◽  
Different Temperatures

scholarly journals Hard Coating Materials Based on Photo-Reactive Silsesquioxane for Flexible Application: Improvement of Flexible and Hardness Properties by High Molecular Weight

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1564
Author(s):  
Jong Tae Leem ◽  
Woong Cheol Seok ◽  
Ji Beom Yoo ◽  
Sangkug Lee ◽  
Ho Jun Song
Keyword(s):  
Molecular Weight ◽  
Surface Morphology ◽  
High Molecular Weight ◽  
Sol Gel ◽  
Xrd Analysis ◽  
Polyhedral Oligomeric Silsesquioxanes ◽  
Coating Materials ◽  
Pencil Hardness ◽  
Coated Film ◽  
Flexible Application

EPOSS of polyhedral oligomeric silsesquioxanes (POSS) mixture structure and LPSQ of ladder-like polysilsesquioxane (LPSQ) structure were synthesized via sol–gel reaction. EPSQ had a high molecular weight due to polycondensation by potassium carbonate. The EPSQ film showed uniform surface morphology due to regular double-stranded structure. In contrast, the EPOSS-coated film showed nonuniform surface morphology due to strong aggregation. Due to the aggregation, the EPOSS film had shorter d-spacing (d1) than the EPSQ film in XRD analysis. In pencil hardness and nanoindentation analysis, EPSQ film showed higher hardness than the EPOSS film due to regular double-stranded structure. In addition, in the in-folding (r = 0.5 mm) and out-folding (r = 5 mm) tests, the EPSQ film did not crack unlike the EPOSS coated film.

scholarly journals Effect of calcination temperature on rare earth tailing catalysts for catalytic methane combustion

2020 ◽  
Vol 9 (1) ◽  
pp. 734-743
Author(s):  
Ran Zhao ◽  
ZiChen Tian ◽  
Zengwu Zhao
Keyword(s):  
Rare Earth ◽  
Mine Tailings ◽  
Photoelectron Spectroscopy ◽  
Methane Combustion ◽  
Space Velocity ◽  
High Catalytic Activity ◽  
Reduction Peak ◽  
X Ray ◽  
Different Temperatures ◽  
Bayan Obo

AbstractBayan Obo tailings are rich in rare earth elements (REEs), iron, and other catalytic active substances. In this study, mine tailings were calcined at different temperatures and tested for the catalytic combustion of low-concentration methane. Upon calcination at 600°C, high catalytic activity was revealed, with 50% CH4 conversion at 587°C (space velocity of 12,000 mL/g h). The physicochemical properties of catalysts were characterized using thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, hydrogen temperature-programmed reduction (H2-TPR), and X-ray photoelectron spectroscopy (XPS). Compared to the raw ore sample, the diffraction peak intensity of Fe2O3 increased post calcination, whereas that of CeCO3F decreased. A porous structure appeared after the catalyst was calcined at 600°C. Additionally, Fe, Ce, Ti, and other metal elements were more highly dispersed on the catalyst surface. H2-TPR results revealed a broadening of the reduction temperature range for the catalyst calcined at 600°C and an increase in the reduction peak. XPS analysis indicated the presence of Ce in the form of Ce3+ and Ce4+ oxidation states and the coexistence of Fe in the form of Fe2+ and Fe3+. Moreover, XPS revealed a higher surface Oads/Olatt ratio. This study provides evidence for the green reuse of Bayan Obo mine tailings in secondary resources.

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