scholarly journals SYNTHESIS OF PEROFSKITE-LIKE Co-CONTAINING CATALYST

2020 ◽  
Vol 2 (440) ◽  
pp. 115-119
Author(s):  
G.D. Jetpisbayeva ◽  
B.K. Massalimova ◽  
A.B. Daulet
Keyword(s):  
Perovskite Structure ◽  
Complex Oxide ◽  
Optimal Composition ◽  
Polymer Complexes ◽  
Citrate Method ◽  
Oxidation Processes ◽  
Oxidative Reactions ◽  
Developed Surface ◽  
The Stability ◽  
Xrd Method

There are several approaches to the preparation of catalysts with a developed surface based on oxides with a perovskite structure. Perovskites, due to the possibility of easy variation of chemical composition, make it possible to choose the optimal composition of the catalyst and surface area, and as a result it is possible to influence effectively the selectivity. Perovskite-like LaMeO3 oxides are one of the most promising catalysts for many oxidation processes due to their high activity in oxidative reactions and the stability in aggressive environment. Pekini method (polymer complexes method) and its simplified variant - citrate method are the most widely used for the synthesis of perovskite-like oxides. This article reports about the synthesis of perovskite-like complex oxide LaCoO3 obtained in two ways: hydrothermal, using ethylene glycol, and the citrate method using the template – mesoporous silica KIT-6. The structure of the samples obtained was determined by the XRD method. As a result, it was found that the catalysts have a perovskite structure. Key words: LaCoO3 , perovskite, KIT-6.

ESTIMATING THE STABILITY OF METAL–LIGAND BONDING IN CARBOXYL-CONTAINING POLYMER COMPLEXES BY IR SPECTROSCOPY

2020 ◽  
Vol 61 (12) ◽  
pp. 1876-1887
Author(s):  
T. V. Berestova ◽  
K. N. Nosenko ◽  
O. V. Lusina ◽  
L. G. Kuzina ◽  
E. I. Kulish ◽  
...  
Keyword(s):  
Ir Spectroscopy ◽  
Polymer Complexes ◽  
The Stability ◽  
Metal Ligand

scholarly journals New tolerance factor to predict the stability of perovskite oxides and halides

2019 ◽  
Vol 5 (2) ◽  
pp. eaav0693 ◽  
Author(s):  
Christopher J. Bartel ◽  
Christopher Sutton ◽  
Bryan R. Goldsmith ◽  
Runhai Ouyang ◽  
Charles B. Musgrave ◽  
...  
Keyword(s):  
Perovskite Structure ◽  
Data Analytics ◽  
Functional Materials ◽  
Perovskite Oxides ◽  
Tolerance Factor ◽  
Double Perovskites ◽  
Training Set ◽  
Experimental Dataset ◽  
One Dimensional ◽  
The Stability

Predicting the stability of the perovskite structure remains a long-standing challenge for the discovery of new functional materials for many applications including photovoltaics and electrocatalysts. We developed an accurate, physically interpretable, and one-dimensional tolerance factor, τ, that correctly predicts 92% of compounds as perovskite or nonperovskite for an experimental dataset of 576 ABX3 materials (X = O2−, F−, Cl−, Br−, I−) using a novel data analytics approach based on SISSO (sure independence screening and sparsifying operator). τ is shown to generalize outside the training set for 1034 experimentally realized single and double perovskites (91% accuracy) and is applied to identify 23,314 new double perovskites (A2BB′X6) ranked by their probability of being stable as perovskite. This work guides experimentalists and theorists toward which perovskites are most likely to be successfully synthesized and demonstrates an approach to descriptor identification that can be extended to arbitrary applications beyond perovskite stability predictions.

scholarly journals ELECTROCHEMICAL EVALUATION OF THE STABILITY OF ASCORBIC ACID IN WHEY FROM CHEESE AND RICOTTA

2017 ◽  
Vol 14 (27) ◽  
pp. 51-55
Author(s):  
Lucélia HOEHNE ◽  
Adriano GENNARI ◽  
Eduardo Miranda ETHUR ◽  
Maurício HILGEMANN ◽  
Claucia Fernanda Volken SOUZA ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Cyclic Voltammetry ◽  
Vitamin C ◽  
Antioxidant Capacity ◽  
Electrochemical Techniques ◽  
Factors Affecting ◽  
Oxidative Reactions ◽  
Antioxidant Evaluation ◽  
The Stability ◽  
Electrochemical Evaluation

Ascorbic acid has aroused particular interest due to its antioxidant capacity, which can prevent oxidative reactions. Cyclic voltammetry stands out as one of the main electrochemical techniques for antioxidant evaluation. The cheese and ricotta whey are subproducts of the dairy, and have several components that allow its use in various foods. The enrichment of subproducts with essential substances in food may make its use even more attractive by industries. Therefore, the aim of this study was to evaluate the stability of ascorbic acid in cheese and ricotta whey using cyclic voltammetry. For this, the cheese and ricotta whey were collected from a dairy industry of the Vale do Taquari-RS and were fortified with ascorbic acid and its stability was evaluated according to the electrochemical profiles of the samples. With the data obtained, it was concluded that one of the factors affecting directly the stability of ascorbic acid was the pH, but more studies are needed to evaluate other interfering stability of vitamin C.

Peroviskites Synthesis to SOFC Anodes

2014 ◽  
Vol 805 ◽  
pp. 498-503
Author(s):  
Leonardo Pacheco Wendler ◽  
Kethlinn Ramos ◽  
Adriana Scoton Antonio Chinelatto ◽  
Adilson Luiz Chinelatto
Keyword(s):  
Solid Oxide Fuel Cells ◽  
Perovskite Structure ◽  
Catalytic Properties ◽  
Pechini Method ◽  
Hydrocarbon Fuel ◽  
Scanning Electronic Microscopy ◽  
X Ray ◽  
Bet Isotherm ◽  
Sofc Anode ◽  
The Stability

The traditional Ni-based anodes are capable of providing a good power output using H2and CO fuels, but sulfur contamination in any hydrocarbon fuel is a problem. Thus, perovskite structure materials containing lanthanum have been widely studied as electrodes for solid oxide fuel cells (SOFCs), due to its electrical properties. In this work was investigated the obtain of the perovskite structure LaCr0.5Ni0.5O3, by Pechini method, and its suitability as SOFC anode. The choice of this composition was based on the stability provided by chromium and the catalytic properties of nickel. After preparing the resins, the samples were calcined at 300oC, 600oC, 700oC and 850oC. The resulting powders were characterized by X-ray, X-ray fluorescence spectroscopy, He pycnometry, specific surface area by BET isotherm and scanning electronic microscopy. The obtaining of the powders of LaCr0.5Ni0.5O3through the Pechini method proved to be effective for temperatures above 850oC.

scholarly journals Устойчивость полимерных композитов с оксидом вольфрама к воздействию электронного облучения

2020 ◽  
Vol 90 (1) ◽  
pp. 115
Author(s):  
Н.И. Черкашина
Keyword(s):  
Tungsten Oxide ◽  
Outer Space ◽  
Calculated Data ◽  
Experimental Methods ◽  
Optimal Composition ◽  
Fast Electrons ◽  
Transmission Coefficients ◽  
The Difference ◽  
The Stability ◽  
Number Of Particles

The data on the physicomechanical and thermal properties of polymer composites based on polyimide and tungsten oxide (WO3) are presented. The calculation and experimental methods were used to study the stability of composites against the flow of fast electrons with an energy of 0.5-5 MeV. In the energy range under study, electron ranges in composites with different tungsten oxide contents are presented. The difference in the experimental and calculated data on the range of electrons is ± 15%. The results of modeling the dependence of the transmission coefficients in terms of the number of particles and energy depending on the thickness of the composite of optimal composition containing 60 wt. % WO3, in the case of electron incidence both perpendicularly (φ = 0) and at φ = 45 °. The possibility of using the developed composite to protect against electronic radiation in outer space is established.

scholarly journals Obtaining and properties of CdB4O7 polycrystals, doped with Cr3+ions

2020 ◽  
Author(s):  
Т.Н. ХАМАГАНОВА
Keyword(s):  
High Temperature ◽  
Solid State ◽  
Melting Point ◽  
Solid Solutions ◽  
Solid State Reactions ◽  
Optimal Composition ◽  
Dsc Method ◽  
First Time ◽  
Rhombic System ◽  
Xrd Method

Впервые поликристаллические фазы Cd1-xB4O7 : xCr3+ (x = 0,03; 0,05 и 0,07) и исходная матрица CdB4O7 синтезированы высокотемпературными твердофазными реакциями при 850 °С. Методом РФА показано, что твердые растворы кристаллизуются в ромбической сингонии (пр. гр. Pbca). Методом ДСК определена температура плавления (Тпл. = 974 °С) бората Cd1-xB4O7 : 0.03 Cr3+. Построением кривых высвечивания в области 20–400 °С проведены термолюминесцентные исследования. Выявлен оптимальный состав люминофора Cd1-xB4O7 : 0.03 Cr3+ с максимальной интенсивностью свечения. For the first time the polycrystalline phases Cd1-xB4O7 : x Cr3 + (x = 0.03; 0.05 and 0.07) and the initial CdB4O7 matrix were synthesized by high-temperature solid-state reactions at 850°C. The XRD method showed that solid solutions crystallize in rhombic system (sp. gr. Pbca). Using the DSC method, the melting point (Tm.p. = 974°С) of Cd1-xB4O7 : 0.03 Cr3 + borate was determined. Thermoluminescent studies were performed by plotting the emission curves in the range of 20–400°С. The optimal composition of the phosphor Cd1-xB4O7 : 0.03 Cr3 + with a maximum luminescence intensity was revealed.

scholarly journals VITAMIN D NANOCAPSULATION

2021 ◽  
Vol 64 (5) ◽  
pp. 98-105
Author(s):  
Taisiya S. Gutnova ◽  
Dmitry V. Kompantsev ◽  
Alexey A. Gvozdenko ◽  
Vasily N. Kramarenko ◽  
Andrey V. Blinov
Keyword(s):  
Vitamin D ◽  
Vitamin D3 ◽  
The Body ◽  
Optimal Composition ◽  
Quantitative Content ◽  
Biological Potential ◽  
Low Toxicity ◽  
The Stability ◽  
Biopharmaceutical Properties ◽  
Selection Of

The main objective of the planned experiment is to obtain a stabilized nanoemulsion of vitamin D3, followed by obtaining nanocapsules of vitamin D3 with a high biological potential, as well as to analyze the spatial (dimensional) characteristics, to study the stability and stability of the resulting product. In the presented study, the physicochemical and technological properties of the vitamin D substance were studied and the optimal ultradispersion mode was selected. The composition is experimentally established and a technology for obtaining laboratory samples of nanocapsules is proposed. The shape and size of the obtained nanocapsules with vitamin D were studied. Based on the developed experimental model, the optimal composition of nanocapsules was obtained. The quantitative content of vitamin D3 in the analyzed sample of nanocapsules was 76.9% with a holding time of 2.0 min. The results of studying the stability and stability of vitamin D nanocapsules proved their stability for 12 months. The developed vitamin D nanocapsules are a way of modifying the vitamin D substance for the subsequent production of tablets with improved biopharmaceutical properties. The selection of the composition of excipients based on the prediction of their properties, as well as the technology for producing nanocapsules, allows to increase the duration of the therapeutic effect while simultaneously reducing the maximum concentration of the drug in the body. The optimal composition of solubilizers for achieving a more complete, rapid and targeted dissolution of the active substance in a given part of the intestine has been experimentally confirmed. The aim of the study is to obtain a quality drug with improved properties such as adequate bioavailability, safety, low toxicity, no side effects and controlled release.

scholarly journals Effect of Grafted Hydroquinone on the Acid-Base Properties of Poly(acrylic acid) in the Presence of Copper (II)

2015 ◽  
Vol 2015 ◽  
pp. 1-7
Author(s):  
Nabila Bensacia ◽  
Saâd Moulay ◽  
François Garin ◽  
Ioana Fechete ◽  
Anne Boos
Keyword(s):  
Acrylic Acid ◽  
Coordination Number ◽  
Potentiometric Titration ◽  
Stability Constants ◽  
Acid Base ◽  
Polymer Complexes ◽  
Ionic Environment ◽  
The Stability ◽  
Hasselbalch Equation ◽  
Poly Acrylic Acid

Potentiometric titration of poly(acrylic acid) and hydroquinone-functionalized poly(acrylic acid) was conducted in the presence of copper (II). The effects of hydroquinone functionalizing and copper (II) complexing on the potentiometric titration of poly(acrylic acid) were studied in an ionic environment and in its absence. Henderson-Hasselbalch equation was applied to assess its validity for this titration. Coordination number and the stability constants of the copper- (II-)complexed polymers were determined, and results showed the formation of mostly monodentate and bidentate copper- (II-)polymer complexes.

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