scholarly journals The Effect of Tartaric and Citric Acid as a Complexing Agent on Defect Structure and Conductivity of Copper Samarium Co-doped Ceria Prepared by a Sol-Gel Auto-Combustion Method

2021 ◽  
Author(s):  
Kornrawit Duangsa ◽  
Apishok Tangtrakarn ◽  
Charustporn Mongkolkachit ◽  
Pavadee Aungkavattana ◽  
Klitsada Moolsarn
Keyword(s):  
Citric Acid ◽  
Sol Gel ◽  
Complexing Agents ◽  
Total Conductivity ◽  
Average Particle ◽  
Doped Ceria ◽  
Temperature Conductivity ◽  
Metal Nitrates ◽  
Auto Combustion ◽  
Co Doped

Abstract A copper samarium co-doped ceria (CSDC) (Cu0.01Sm0.19Ce0.80O2-δ) nanoparticles were synthesized via a sol-gel auto-combustion of metal nitrates with two different complexing agents including tartaric acid (TA) and citric acid (CA). A reference sample was metal nitrates in deionized water (DI). TGA/DSC of gels reveals endothermic reaction for CSDC/DI but exothermic behavior for CSDC/TA or CSDC/CA during oxide formation. The CA route exhibits the highest energy release since it has extensive formation of metals-citrate. From SEM, the as-synthesized morphologies of DI, TA and CA routes show porous sheet-like, fluffy-like and foamy-like structure, respectively. XRD patterns of calcined CSDCs denote a cubic fluorite structure. The average particle sizes from TEM vary in the range of 30-32 nm. The relative oxygen vacancy (VO) concentrations for calcined and sintered CSDCs from Raman analysis are as follow; CSDC/CA>CSDC/TA>CSDC/DI. Moreover, segregation of (Ce and/or Sm)2O3 and CuO can be observed in Raman spectra for calcined and sintered CSDCs. The oxides of copper segregate mostly in sintered CSDC/CA. The XPS results confirm that Ce3+/Ce4+ coexist, and in addition, the Ce3+ represent Ce3+-VO and/or Ce2O3 segregation. The Ce3+ in sintered CSDCs suggest the existence of Ce3+-VO for CSDC/DI and CSDC/CA; however, Ce3+ implied coexisting of Ce3+-VO and Ce2O3 segregation for CSDC/TA. The relative densities of sintered CSDC/DI, CSDC/TA and CSDC/CA are 82.78%, 95.51% and 97.98%, respectively. The enthalpy of association increases with the increasing of porosity and metal oxide segregation. Segregation of CuO increases CSDC/CA’s association enthalpy at low temperature but it does not affect high temperature conductivity of CSDC/CA. The high total conductivity of 0.0271 S/cm was achieved for CSDC/CA at 600 °C.

scholarly journals The Effect of Tartaric Acid and Citric Acid as a Complexing Agent on Defect Structure and Conductivity of Copper Samarium Co-Doped Ceria Prepared by a Sol-Gel Auto-Combustion Method

2021 ◽  
Vol 2021 ◽  
pp. 1-23
Author(s):  
Kornrawit Duangsa ◽  
Apishok Tangtrakarn ◽  
Charusporn Mongkolkachit ◽  
Pavadee Aungkavattana ◽  
Klitsada Moolsarn
Keyword(s):  
Citric Acid ◽  
Grain Boundary ◽  
Tartaric Acid ◽  
Sol Gel ◽  
Cross Linking ◽  
Complexing Agent ◽  
Doped Ceria ◽  
Boundary Conductivity ◽  
Auto Combustion ◽  
Co Doped

Copper samarium co-doped ceria (CSDC) (Cu0.01Sm0.19Ce0.80O2−δ) nanoparticles were synthesized via a sol-gel auto-combustion of metal nitrates without a complexing agent (DI) and with tartaric acid (TA) or citric acid (CA). The solid oxide formation of CSDC/DI corresponds to the endothermic stage, whereas that of CSDC/TA and CSDC/CA matches the exothermic stage caused by the decomposition of the metal cross-linking and carbon combustion. The cross-linking occurs more extensively in the CA case as more heat is released in CA than in the TA route. The as-synthesized morphology of CSDC/DI reveals both layered structures and small agglomerated particles, whereas CSDC/TA and CSDC/CA show dense xerogel and porous xerogel, respectively. The cubic fluorite structure for calcined CSDCs was confirmed by XRD. From Raman analysis, calcined CSDC/CA has the lowest amount of copper segregation and the highest relative total oxygen vacancy concentration [ V O • • ]total, whereas calcined CSDC/DI has the highest amount of copper segregation and the lowest [ V O • • ]total. For all samples, copper segregation promotes densification, albeit to varying degrees. The relative densities of CSDC/DI, CSDC/TA, and CSDC/CA pellets are 82.8 ± 2.4%, 95.5 ± 1.8%, and 97.8 ± 0.9%, respectively. The sintered CSDC/DI has the lowest density because some copper segregates and liquid copper in interparticle spaces could evaporate earlier than samples containing a complexing agent, whereas sintered CSDC/CA has the highest density because Cu could slowly diffuse from the Cu-Sm-Ce solid solution to grain boundary regions and then precipitate as CuO. The specific grain boundary conductivity is predominantly influenced by CuO along grain boundaries, which reduces specific grain boundary conductivity and increases the enthalpy of association (ΔHa) at 250–350°C; however, it rarely impacts total grain boundary conductivity at temperatures higher than 400°C. CSDC/CA has slightly higher total conductivity than CSDC/TA despite having more CuO segregation because it has higher density and V O • • .

Preparation of Magnesium-Based Cobalt-Ferrites (Co1−xMgxFe2O4) Nanoparticles by Sol–Gel Auto Combustion Method

2017 ◽  
Vol 17 (01n02) ◽  
pp. 1760012
Author(s):  
S. Gowreesan ◽  
A. Ruban Kumar
Keyword(s):  
Particle Size ◽  
Structural Parameters ◽  
Sol Gel ◽  
Average Particle Size ◽  
Combustion Method ◽  
Dielectric Behavior ◽  
Powder Xrd ◽  
Average Particle ◽  
Cobalt Ferrites ◽  
Auto Combustion

The scope of the present work is in enhancing the particle size, and dielectric properties of Mg-substituted Cobalt ferrites nanoparticles prepared by sol–gel auto combustion method. The different ratios of Mg-substituted Co Ferrites (Co[Formula: see text]MgxFe2O4([Formula: see text], 0.05, 0.10, 0.15, 0.20 and 0.30)) are calcinated at 850[Formula: see text]C. The synthesized nanoparticles were characterized by powder XRD, FTIR, FE-SEM, EDX techniques and dielectric behavior. The structural parameters were confirmed from powder XRD and the average particle size is obtained from 39 to 67 nm due to the substitution of Mg[Formula: see text] which was calculated by Debye Scherrer’s formula. FE-SEM showed the surface morphology of the different ratio of the sample. The dielectric loss has measured the frequency range of 50[Formula: see text]Hz–5[Formula: see text]MHz. From electrical modulus, conductivity relaxation and thermal activation of charge carriers has been discussed.

scholarly journals Investigation of Structural and Magnetic Properties of Multiferroic La1-Xyxfeo3perovskites, Prepared by Citrate Auto-Combustion Technique

2019 ◽  
Vol 15 ◽  
pp. 6056-6077
Author(s):  
Ahmed Hassan Ibrahim ◽  
Yehia Mohammed Abbas ◽  
Shehab Esmail Mohammed ◽  
Ahmed Bakry Mansour
Keyword(s):  
Magnetic Properties ◽  
Sol Gel ◽  
Particle Diameter ◽  
Average Particle ◽  
Microscopy Imaging ◽  
Transmission Microscopy ◽  
Auto Combustion ◽  
Structural And Magnetic Properties ◽  
Combustion Technique ◽  
Synchrotron Xrd

In this work, we studied the structural and magnetic properties of multiferroic La1-xYxFeO3 perovskites, (x= 0.0, 0.05, 0.1, 0.15, 0.25 and 0.3) which synthesized through Sol-gel auto-combustion technique using a citric acid as a fuel. The room temperature synchrotron X-ray diffraction (XRD) analysis revealed that the all the synthesized samples consisted of the polycrystalline orthorhombic structure perovskites(space group pnma), and tolerance factor confirmed the phase stability of the prepared perovskite system.The Williamson-Hall plot based on synchrotron XRD data were employed to estimate the average particle diameter and varies from 18 nmto 27.8 nm.For a deeper insight of the crystal structure, high resolution transmission microscopy imaging (HRTEM) was performed. The estimated values of crystallite size from HRTEM and synchrotron XRD data were coincident. Many of crystallographic parameters and electron density measurements were calculated by Rietveld refinement of synchrotron XRD data. La1-xYxFeO3 perovskite crystalsarecanted antiferromagnets with a weak ferromagnetism in room temperature.The magnetic properties were gotten through analyzing the magnetization versus temperature M(T) and M(H) hysteresis loop which characterized by a vibrating sample magnetometer (VSM). The molecular structure showed the decrease of the tilting of the octahedra <FeO6> with increasing Y content trying to strengthen the ferromagnetic character. Selected Area Electron Diffraction (SAED) patterns of the investigated samples exhibited spotty ring patterns,confirming the polycrystalline character.The orthoferrite La1-xYxFeO3 crystalsare a promising candidate for optical device applications in broad temperature range and high power system.

Synthesis and Characterization of Co-Doped Ceria Ceramics by Sol-Gel Method

2011 ◽  
Vol 70 (3) ◽  
pp. 143-147 ◽  
Author(s):  
S. Ramesh ◽  
K. C. James Raju ◽  
C. Vishnuvardhan Reddy
Keyword(s):  
Sol Gel ◽  
Synthesis And Characterization ◽  
Doped Ceria ◽  
Gel Method ◽  
Sol Gel Method ◽  
Co Doped

SYNTHESIS OF THE NANOCRYSTALLINE NICKEL FERRITE BY A NOVEL MECHANO SOL–GEL AUTO-COMBUSTION METHOD

2011 ◽  
Vol 25 (11) ◽  
pp. 855-861 ◽  
Author(s):  
M. SHAHMIRZAEI ◽  
S. A. SEYYED EBRAHIMI ◽  
R. DEHGHAN
Keyword(s):  
Nickel Ferrite ◽  
Single Phase ◽  
Sol Gel ◽  
Combustion Method ◽  
High Energy ◽  
Milling Process ◽  
Nanocrystalline Powder ◽  
High Energy Milling ◽  
Metal Nitrates ◽  
Auto Combustion

In this work, a novel method of mechano sol–gel auto-combustion has been developed for production of single phase nickel ferrite nanocrystalline powder, consisting of a sol–gel auto-combustion synthesis followed by a high energy milling process before calcination. Sol–gel auto-combustion was carried out using a gel including citric acid as a reductant and metal nitrates as oxidants. This gel exhibited a self-propagating behavior after ignition in air. The effects of the intermediate high energy milling on the physical properties of the final product after calcination were investigated. The results showed that with a high energy milling of the sol–gel auto-combusted powders with a ball-to-powder mass ratio of 20 for 20 h, the temperature of calcination for synthesis of the single phase ferrite reduced from 1000°C to 700°C and the size of the ferrite crystallites decreased from 72 nm to 15 nm.

scholarly journals Composition, Microstructure, and Electrical Properties Control of the Powders Synthesized by Sol–Gel Auto-Combustion Method Using Citric Acid as the Fuel

2017 ◽  
Vol 12 (1) ◽  
Author(s):  
Bogdan K. Ostafiychuk ◽  
Larysa S. Kaykan ◽  
Julia S. Kaykan ◽  
Bogdan Ya. Deputat ◽  
Olena V. Shevchuk
Keyword(s):  
Citric Acid ◽  
Electrical Properties ◽  
Sol Gel ◽  
Combustion Method ◽  
Auto Combustion

Synthesis of (Ba,Ti)-Doped Apatite-Type Lanthanum Silicate Nano-Sized Powders via Microwave-Assisted Sol-Gel Auto-Combustion Route

2013 ◽  
Vol 652-654 ◽  
pp. 882-885 ◽  
Author(s):  
Ran Wu ◽  
Jia Mei Ye ◽  
Qi Zhao Li ◽  
Sheng Yun Wang ◽  
Xiu Lei Chen ◽  
...  
Keyword(s):  
Particle Size ◽  
Citric Acid ◽  
Sol Gel ◽  
Lanthanum Nitrate ◽  
Microwave Assisted ◽  
Auto Combustion ◽  
Combustion Route ◽  
Lanthanum Silicate ◽  
Apatite Type

In this paper, (Ba,Ti)-doped lanthanum silicate nano-sized powders have been synthesized via microwave assisted sol-gel auto-combustion route by using TEOS and lanthanum nitrate as the starting materials, citric acid and glycol as chelators. Both the phase compositions and morphologies of the obtained powders have been characterized. The results indicated that: the synthesized nano powders were characterized as fluffy aggregates with the particle size ranging from 50 to 100nm. As the doping contents of Ba increased, the crystalline sizes decreased and the aggregation were deteriorated, while the particle size decreased from 120nm to 80nm and the aggregation between particles were halted as the doping contents of Ti increased.

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