scholarly journals Influence of Cobalt Substitution in LaNiO3 Nanoperovskite on Catalytic Propylene Oxidation

2021 ◽  
Vol 13 (3) ◽  
pp. 961-969
Author(s):  
T. Vaz ◽  
S. M. Gurav ◽  
A. V. Salker
Keyword(s):  
Perovskite Phase ◽  
Oxidation Reactions ◽  
Transition Elements ◽  
Scanning Calorimetry ◽  
Total Oxidation ◽  
Propylene Oxidation ◽  
Xrd Diffraction ◽  
Cobalt Substitution ◽  
Co Precipitation ◽  
Oxidation Efficiency

Perovskite-type oxides with transition elements offer promising potential as catalysts in total oxidation reactions. The present work reports the synthesis of crystalline lanthanum nickelates and cobaltates and their intermediate nanomaterials compositions LaNi1-XCoXO3 (x = 0.3, 0.5, and 0.7) at 800 ºC by co-precipitation precursor technique for structural, morphological, and total propylene oxidation catalytic activity. The evolution of the crystal structure and formation of the perovskite phase were analyzed by X-ray diffraction, Thermo Gravimetry Analysis (TGA) / Differential Scanning Calorimetry (DSC), Fourier Transformed Infra-Red (FTIR), Atomic Absorption Spectroscopy (AAS), Scanning Electron Microscopy (SEM), Brunauer–Emmett–Teller (BET), Electron Spin Resonance (ESR) techniques. The terminal compounds LaNiO3, LaCoO3, and their intermediates compositions were identified to be single-phase and are indexed to rhombohedral structures. The bonding characteristics were studied by FTIR spectroscopy. On substitution of Ni with Co in B-site, the slight distortion in XRD diffraction peaks were observed. These compounds show a considerable increase in the activity of propylene oxidation to carbon dioxide. This study aims at understanding the effect of B– site substitution in the lattice of LaNiO3 and their influence on catalytic propylene oxidation efficiency.

scholarly journals Influence of Cobalt Substitution in LaMnO3 on Catalytic Propylene Oxidation

2021 ◽  
Vol 21 (5) ◽  
pp. 1244
Author(s):  
Teotone Inas Mariano Vaz ◽  
Sridhar Maruti Gurav ◽  
Arun Vithal Salker
Keyword(s):  
Perovskite Phase ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Total Oxidation ◽  
Propylene Oxidation ◽  
Xrd Diffraction ◽  
Structure Morphology ◽  
Cobalt Substitution ◽  
Co Precipitation ◽  
Oxidation Efficiency

Perovskite-type structures LaBO3 with the compositions of LaMn1-xCoxO3 (x = 0.0, 0.3, 0.5, 0.7, and 1.0) were synthesized at 800 °C by a modified co-precipitation precursor technique for total oxidation of propylene, as a model test of the hydrocarbon oxidation reaction. Details concerning the evolution of the crystal structure, morphology, and crystallite size were performed by X-ray diffraction (XRD), Thermo Gravimetry Analysis (TGA)/Differential Scanning Calorimetry (DSC), Fourier Transform Infra-Red (FTIR), Atomic Absorption Spectroscopy (AAS), Scanning Electron Microscopy (SEM), and Electron Spin Resonance (ESR) techniques. All compositions were identified to be single-phase and are indexed to rhombohedral structures. TG/DSC technique evidenced a temperature of 330 °C needed for the precursor as the start point and 800 °C completion for perovskite phase formation. Slight distortion in XRD diffraction peaks was observed on substituting manganese with cobalt in B-site, and new peaks emerged. An attempt has been made to understand the effect of the B-site substitution of Co3+ ions in the lattice of LaMnO3 and their influence on catalytic total propylene oxidation efficiency. These compounds show a considerable increase in the activity of propylene oxidation to carbon dioxide and water and could be explored for hydrocarbon pollution control.

scholarly journals Lanthanum based high surface area perovskite-type oxide and application in CO and propane combustion

2018 ◽  
Vol 34 (1) ◽  
pp. 31
Author(s):  
Paulo Roberto Nagipe Da Silva ◽  
Ana Brígida Soares
Keyword(s):  
Catalytic Activity ◽  
Photoelectron Spectroscopy ◽  
Perovskite Phase ◽  
High Surface ◽  
High Surface Area ◽  
Propane Combustion ◽  
Total Oxidation ◽  
X Ray ◽  
Co Precipitation ◽  
Perovskite Type

The perovskite-type oxides using transition metals present a promising potential as catalysts in total oxidation reaction. The present work investigates the effect of synthesis by oxidant co-precipitation on the catalytic activity of perovskite-type oxides LaBO3 (B= Co, Ni, Mn) in total oxidation of propane and CO. The perovskite-type oxides were characterized by means of X-ray diffraction, nitrogen adsorption (BET method), thermo gravimetric and differential thermal analysis (ATG-DTA) and X-ray photoelectron spectroscopy (XPS). Through a method involving the oxidant co-precipitation it’s possible to obtain catalysts with different BET surface areas, of 33-44 m2/g, according the salts of metal used. The characterization results proved that catalysts have a perovskite phase as well as lanthanum oxide, except LaMnO3, that presents a cationic vacancies and generation for known oxygen excess. The results of catalytic test showed that all oxides have a specific catalytic activity for total oxidation of CO and propane even though the temperatures for total conversion change for each transition metal and substance to be oxidized.

scholarly journals Comprehensive Thermal Characteristics of Different Cultivars of Flaxseed Oil (Linum usittatissimum L.)

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1958
Author(s):  
Jolanta Tomaszewska-Gras ◽  
Mahbuba Islam ◽  
Liliana Grzeca ◽  
Anna Kaczmarek ◽  
Emilia Fornal
Keyword(s):  
Differential Scanning Calorimetry ◽  
Heating Rate ◽  
Fatty Acid Content ◽  
Thermal Characteristics ◽  
Principal Component ◽  
Flaxseed Oil ◽  
Scanning Calorimetry ◽  
Total Oxidation ◽  
Increasing Temperature ◽  
Linear Correlations

The aim of this study was to describe the thermal properties of selected cultivars of flaxseed oil by the use of the differential scanning calorimetry (DSC) technique. The crystallization and melting profiles were analyzed depending on different scanning rates (1, 2, 5 °C/min) as well as oxidative induction time (OIT) isothermally at 120 °C and 140 °C, and oxidation onset temperatures (Ton) at 2 and 5 °C/min were measured. The crystallization was manifested as a single peak, differing for a cooling rate of 1 and 2 °C/min. The melting curves were more complex with differences among the cultivars for a heating rate of 1 and 2 °C/min, while for 5 °C/min, the profiles did not differ, which could be utilized in analytics for profiling in order to assess the authenticity of the flaxseed oil. Moreover, it was observed that flaxseed oil was highly susceptible to thermal oxidation, and its stability decreased with increasing temperature and decreasing heating rate. Significant negative linear correlations were found between unsaturated fatty acid content (C18:2, C18:3 n-3) and DSC parameters (OIT, Ton). Principal component analysis (PCA) also established a strong correlation between total oxidation value (TOTOX), peroxide value (PV) and all DSC parameters of thermo-oxidative stability.

scholarly journals Phase Transition and Coefficients of Thermal Expansion in Al2−xInxW3O12 (0.2 ≤ x ≤ 1)

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4021
Author(s):  
Andrés Esteban Cerón Cerón Cortés ◽  
Anja Dosen ◽  
Victoria L. Blair ◽  
Michel B. Johnson ◽  
Mary Anne White ◽  
...  
Keyword(s):  
Phase Transition ◽  
Thermal Expansion ◽  
Thermal Shock ◽  
Monoclinic Phase ◽  
Ceramic Materials ◽  
Precipitation Method ◽  
Scanning Calorimetry ◽  
Orthorhombic Crystal ◽  
Co Precipitation

Materials from theA2M3O12 family are known for their extensive chemical versatility while preserving the polyhedral-corner-shared orthorhombic crystal system, as well as for their consequent unusual thermal expansion, varying from negative and near-zero to slightly positive. The rarest are near-zero thermal expansion materials, which are of paramount importance in thermal shock resistance applications. Ceramic materials with chemistry Al2−xInxW3O12 (x = 0.2–1.0) were synthesized using a modified reverse-strike co-precipitation method and prepared into solid specimens using traditional ceramic sintering. The resulting materials were characterized by X-ray powder diffraction (ambient and in situ high temperatures), differential scanning calorimetry and dilatometry to delineate thermal expansion, phase transitions and crystal structures. It was found that the x = 0.2 composition had the lowest thermal expansion, 1.88 × 10−6 K−1, which was still higher than the end member Al2W3O12 for the chemical series. Furthermore, the AlInW3O12 was monoclinic phase at room temperature and transformed to the orthorhombic form at ca. 200 °C, in contrast with previous reports. Interestingly, the x = 0.2, x = 0.4 and x = 0.7 materials did not exhibit the expected orthorhombic-to-monoclinic phase transition as observed for the other compositions, and hence did not follow the expected Vegard-like relationship associated with the electronegativity rule. Overall, compositions within the Al2−xInxW3O12 family should not be considered candidates for high thermal shock applications that would require near-zero thermal expansion properties.

Total oxidation of propane over Cu-Mn mixed oxide catalysts prepared by co-precipitation method

2011 ◽  
Vol 28 (4) ◽  
pp. 1139-1143 ◽  
Author(s):  
Moon Hyeon Kim ◽  
Kyung Ho Cho ◽  
Chae-Ho Shin ◽  
Seong-Eun Kang ◽  
Sung-Won Ham
Keyword(s):  
Mixed Oxide ◽  
Oxide Catalysts ◽  
Precipitation Method ◽  
Total Oxidation ◽  
Mixed Oxide Catalysts ◽  
Co Precipitation

Comparing study of the effect of the CeO2-based carrier materials on the total oxidation of CO, methane, and propane over RuO2

2021 ◽  
Author(s):  
Zheng Wang ◽  
Omeir Khalid ◽  
Wei Wang ◽  
Yu Wang ◽  
Tim Weber ◽  
...  
Keyword(s):  
Co Oxidation ◽  
Intrinsic Activity ◽  
Oxidation Reactions ◽  
Oxidation Of Co ◽  
Propane Combustion ◽  
Total Oxidation ◽  
Carrier Material ◽  
Highly Dispersed ◽  
Carrier Materials

The effect of the carrier material on the intrinsic activity of three catalytic total oxidation reactions, namely CO oxidation as well as methane and propane combustion over highly dispersed RuO2...

The Influence of Calcination Temperature on Quantitative Phase of Hematite from Iron Stone Tanah Laut

2015 ◽  
Vol 1112 ◽  
pp. 489-492
Author(s):  
Ali Mufid ◽  
M. Zainuri
Keyword(s):  
Particle Size ◽  
Calcination Temperature ◽  
Thermo Gravimetric Analysis ◽  
Precipitation Method ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Particle Size Analyzer ◽  
Co Precipitation

This research aims to form particles of hematite (α-Fe2O3) with a basis of mineral iron ore Fe3O4 from Tanah Laut. Magnetite Fe3O4 was synthesized using co-precipitation method. Further characterization using X-ray fluorescence (XRF) to obtain the percentage of the elements, obtained an iron content of 98.51%. Then characterized using thermo-gravimetric analysis and differential scanning calorimetry (TGA-DSC) to determine the calcination temperature, that at a temperature of 445 °C mass decreased by 0.369% due to increase in temperature. Further Characterization of X-ray diffraction (XRD) to determine the phases formed at the calcination temperature variation of 400 °C, 445 °C, 500 °C and 600 °C with a holding time of 5 hours to form a single phase α-Fe2O3 hematite. Testing with a particle size analyzer (PSA) to determine the particle size distribution, where test results indicate that the α-Fe2O3 phase of each having a particle size of 269.7 nm, 332.2 nm, 357.9 nm, 412.2 nm. The best quantity is shown at a temperature of 500 °C to form the hematite phase. This result is used as the calcination procedure to obtain a source of Fe ions in the manufacture of Lithium Ferro Phosphate.

scholarly journals The Effect of Nanosizing on the Oxidation of Partially Oxidized Copper Nanoparticles

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2878
Author(s):  
Jindřich Leitner ◽  
David Sedmidubský ◽  
Michal Lojka ◽  
Ondřej Jankovský
Keyword(s):  
Copper Nanoparticles ◽  
Scanning Transmission Electron Microscopy ◽  
Oxidation Mechanism ◽  
Oxidation Reactions ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Final State ◽  
Micro Particles ◽  
Transmission Electron ◽  
Scanning Transmission

Copper nanoparticles are of great interest in various applications, such as catalysis, cooling fluids, conductive inks or for their antibacterial activity. In this paper, the thermal behavior of copper nanoparticles was studied using thermogravimetry, differential thermal analysis and differential scanning calorimetry. Original Cu samples as well as the products of oxidation were analysed by X-ray diffraction, scanning/transmission electron microscopy and energy dispersive spectroscopy. A step-by-step oxidation mechanism during the oxidation of Cu nano-powders was observed. The Cu-nano oxidation starts slightly above 150 °C when bulk copper does not yet react. The dominant oxidation product in the first step is Cu2O while CuO was identified as the final state of oxidation. Our results confirm an easier oxidation process of Cu-nano than Cu-micro particles, which must be attributed to kinetic not thermodynamic aspects of oxidation reactions.

Study on Sn-Fe-Cr Composite Oxides: Novel, Active and Thermally Stable Catalysts for CH4 Total Oxidation

2002 ◽  
Vol 216 (7) ◽  
Author(s):  
X. Wang ◽  
Y. Xie
Keyword(s):  
Thermal Stability ◽  
Metal Oxide ◽  
Specific Surface ◽  
Redox Reaction ◽  
Metal Oxide Catalysts ◽  
Total Oxidation ◽  
Surface Areas ◽  
Composite Oxides ◽  
Specific Surface Areas ◽  
Co Precipitation

With the combination of redox reaction and co-precipitation, a series of Sn-Fe-Cr composite metal oxide catalysts with various compositions were prepared, which exhibit higher specific surface areas, thermal stability and CH

PREPARATION AND CHARACTERIZATION OF BIOACTIVE COMPOSITES OF PCL/BIOACTIVE FILLERS

2010 ◽  
Vol 24 (01n02) ◽  
pp. 128-135 ◽  
Author(s):  
YING LI ◽  
CHI MUN CHEAH ◽  
HENGKY CHANG ◽  
LEONARD LOH ◽  
ADELINE KUM
Keyword(s):  
Material Design ◽  
Precipitation Reaction ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Composition Structure ◽  
Co Precipitation ◽  
Bioactive Composites ◽  
The Relationship ◽  
Substitute Materials

A variety of bioactive composites have been invested over the last two decades as substitute materials for diseased or damaged tissues in the human body. In this paper, bioactive composites were prepared using polycaprolactone ( PCL ) and hydroxyapatite ( HA ). The influence of micro-sized and nano-sized HA on composite properties was investigated. The nano- HA was prepared by wet chemical co-precipitation reaction method. Studies of biocomposite specimen morphology were performed by Field-emission scanning electron microscopy (SEM). XRD (X-Ray Diffraction) and DSC (Differential scanning calorimetry) were used to assess the crystal structure of HA and thermal properties of the composites, respectively. The synthesized nano- HA is found to be of high purity HA structure. The relationship between composition, structure and properties was studied. Different methods to prepare uniform composites were tried, and the outcome of this work suggests that by proper manipulation of biodegradable polymers and bioactive ceramics through material design, bioactive composites with controlled properties might be achievable.

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