Heating In Air Research Articles

Environmental response characteristics of epitaxial superconducting La0.8Sr0.2NiO2 thin films

Despite the discovery of superconducting properties in thin films with an infinite-layer structured nickelate has paved the way for exploring unconventional superconductivity, opening up new possibilities in this field. However, the challenges related to fabricating these samples have greatly restricted research in this area. In this study, we successfully fabricated superconducting thin films of La0.8Sr0.2NiO2 and investigated their tolerance to different environmental factors. To analyze the stability of the superconducting La0.8Sr0.2NiO2 thin films, we assessed their tolerance to temperature by examining the peak intensities in X-ray diffraction (XRD) and monitoring the changes in resistance curves at varying temperatures. In addition, we investigated the films’ sensitivity to acidity and alkalinity by immersing them in acidic and alkaline solutions for various durations. We also studied the stability of the thin films under various conditions, including heating in air, heating in a vacuum, exposure to acid and alkali, as well as exposure to the organic solvent acetone solution. Our findings highlight the successful preparation of superconducting La0.8Sr0.2NiO2 thin films and shed light on their stability in different environments. This research provides valuable insights for further exploration of their potential applications and laid the foundation for advancements in the field of unconventional superconductivity.

Synthesis of graphene mesosponge using CaO nanoparticles formed from CaCO3

While graphene mesosponge (GMS) is a new type of mesoporous material with the potential for a variety of applications, its synthesis process requires costly templates such as Al2O3 and MgO nanoparticles. In this study, we present a new synthesis method for GMS, which achieves a high specific surface area of 1720 m2 g1 by employing calcium oxide (CaO) nanoparticles as templates. The CaO nanoparticles with an approximate diameter of 86nm are formed through the thermal decomposition of calcium carbonate nanoparticles. However, the calcium carbonate nanoparticles contain a small amount of Mg (2wt%), and the thermal decomposition process also yields impurities, including Mg. When the CaO nanoparticles, including the Mg-based impurities, are subjected to chemical vapor deposition, the CaO surface can be coated with a thin carbon layer, primarily consisting of single-layer graphene through the specific catalysis of the CaO surface in facilitating the CH4-to-C conversion reactions. However, at the same time, the presence of Mg-based impurities leads to the formation of low-crystalline carbons, which have a detrimental effect on the subsequent high-temperature annealing at 1800 °C, following the template removal process, resulting in an excessive number of edge sits in the GMS. We have found that the harmful low-crystalline carbons can be eliminated through heat treatment in air at 350 °C. By adopting such a removal process, high-quality GMS with a minimal number of edge sites can be produced.

Температурные изменения в мясных изделиях при жарке в пароконвекционных печах

Combination steam ovens, or combi steamers, have entered all spheres of food production, including the meat industry. Their rational use requires a scientific and practical foundation. This research featured the changes in mean volume temperature and temperature gradient that occur in meat products (one-dimensional bodies with different nutrient compositions) during heat treatment in dry air and a steam-air mix.
 The research involved two samples of meat products with different moisture and fat contents. The chicken fillet sample had a moisture content of 74.5% and a fat content of 1.9% while the pork shoulder sample had a moisture content of 55.1% and a fat content of 29.4%. Shaped as a one-dimensional cylinder and a plate, the samples were subjected to heating at the temperature range of 160–240°C in a Unox-203G steam-convection oven (Italy). Dry air and a steam-air mix with a humidity of 80–85% served as a heating medium. The temperature was measured using thermocouples attached to a Sosna-004 meter.
 The research revealed some patterns in the mean volume temperature and temperature gradient. The temperature gradient involved three stages during processing in a steam-air mix and four stages when treated with dry air. The change in the mean volume temperature for the steam-air mix could be described by a power law equation; the dry air treatment was described using a linear equation. When heated in dry air, the rate of change in the temperature gradient was constant at first but started to decrease at a certain stage. The change rate in the mean volume temperature remained low for 5 min and started to increase onwards, maintaining its value until the end of the process. When heated in a steam-air mix, the change rate in the temperature gradient dropped to its minimum in 4–5 min and started to grow. The mean volume temperature demonstrated a high change rate during the first 5 min and went down. The chicken fillet with its low fat content warmed up faster by 13–26% when processed in a steam-air mix and by 9–23% when treated in dry air. The plate-shaped products needed longer heat treatment. The composition and form had no significant effect on the nature of the change in the temperature gradient and mean volume temperature.
 The obtained dependencies made it possible to select the optimal temperature and humidity conditions for convective frying of meat products.

Selenium bioaccesibility after in vitro digestion/fermentation of foods differs in adults and children

Selenium (Se) as essential element regulates the immune, endocrine, reproductive and neurological systems through selenoproteins. More important than its content, is the fraction available to be absorbed (bioaccesibility) to exert its important metabolic functions. The objective of this study was to determine the bioaccessibility of Se (Se-BA) in multiple foods by an in vitro digestion/fermentation method. Samples were subjected to homemade culinary techniques and fermented with feces from healthy adults (HE-AD), and healthy (HE-CH) and unhealthy children (with gluten related disorders, GRD-CH; obesity, OB-CH; or allergy/intolerance to cow's milk proteins, AICM-CH). Se-BA varied largely among samples depending on their vegetal/animal origin, category and type of food. Animal-vs. plant-based foods have higher mean Se concentration and total Se-BA (82.5(±97.5) and 93.6(±8.58) vs. 44.3(±55.6) μg/kg and 77.7(±20.4)%, respectively). In plant-based foods, higher Se-BA values were found in the large intestine (41.0(±25.7) vs. 30.1(±26.7%) in animal-base foods). In comparison to raw foods, the cooking techniques of vegetal- and animal-based foods grouped by heating in liquid media (frying-boiling) or hot air (roasting-grilling) decrease Se-BA in the small intestine (42.5(±27.0) vs. 34.8(±25.1) and 34.0(±24.3), and 75.9(±38.0) vs. 52.4(±28.9) and 71.3(±24.8)%, respectively), while it is increased in the large intestine (36.6(±28.5) vs. 41.3(±24.9) and 44.2(±23.6), and 19.9(±30.4) vs. 39.9(±26.0) and 23.4(±22.7)%, respectively). The higher Se-BA levels in the large intestine found in HE-CH (42.1 (±26.5) vs. HE-AD (35.2(±27.1) and unhealthy children (GRD-CH and OB-CH; 38.0(±24.6) and 35.8(±28.1)%, respectively) could be related to greater demands on growth and specific fermentative microbiota.

Effect of Heat Treatment under Different Atmospheres on the Bonding Properties and Mechanism of Ceramiziable Heat-Resistant Adhesive.

In this study, a heat-resistant adhesive was prepared using molybdenum-phenolic (Mo-PF) resin as the matrix and TiB2 particle as the ceramizable filler for bonding Al2O3 ceramic substrates. Firstly, Fourier transform infrared (FTIR) was used to characterize the chemical structure of the Mo-PF. Subsequently, thermo gravimetric analysis (TGA) and shear strength testing were employed to investigate the effects of heat treatment in different atmospheres on the thermal stability and residual bonding properties of the adhesive. To further explore the bonding mechanism of the adhesive after heat treatment in different atmospheres, scanning electron microscopy (SEM), compressive strength testing, and X-ray diffraction (XRD) were utilized to analyze the microstructure, mechanical strength, and composition evolution of the adhesive at different temperatures. The bonding strength of Al2O3 joints showed a trend of initially decreasing and then increasing after different temperature heat treatment in air, with the shear strength reaching a maximum value of 25.68 MPa after treatment at 1200 °C. And the bonding strength of Al2O3 joints decreased slowly with the increase of temperature in nitrogen. In air, the ceramicization reaction at a high temperature enabled the mechanical strength of the adhesive to rise despite the continuous pyrolysis of the resin. However, the TiB2 filler in nitrogen did not react, and the properties of the adhesive showed a decreasing tendency with the pyrolysis of the resin.

Advanced Ceramics with Dual Functions of Healing and Decomposition.

This study developed advanced ceramic materials with both healing and decomposition functions using a metastable product generated under superheated steam. The developed composite material comprises ZrC particles dispersed in a yttria-stabilized zirconia (YSZ) matrix. After introducing a surface crack of approximately 120 μm on the composite specimen, it showed a complete strength recovery rate after one hour of heat treatment under superheated steam at 400 °C, while it exhibited a decomposition behavior after one hour of heat treatment in air at 400 °C. The XRD analysis of the heat-treated specimens showed that the final product was monoclinic ZrO2 under both steam and air conditions. In other words, full strength recovery in superheated steam was achieved by a chain reaction involving metastable intermediate products derived from H2O, unlike the reaction in air.

Ultra-fast thermal shock behavior of Cr2AlC ceramics up to 1300 °C

Cr2AlC ceramic, an exceptional MAX phase, has been the subject of intensive investigation in this study to elucidate its ultra-fast thermal shock mechanisms. In this investigation, the samples were subjected to rapid induced heating in air and quenching in both air and water, at temperatures ranging from 570 to 1300 °C. Comprehensive analysis was conducted to explore the thermal shock behavior, including changes in strength, phase transformation, and surface/cross-section microstructure at different quenching temperatures. After water quenching, the strength of the samples decreased to 172 and 59 MPa at 570 and 960 °C, respectively, due to factors such as cooling rate, coefficient of thermal expansion (CTE), and stratification of the oxide layer. Notably, at 1150 °C, the presence of a dense oxide layer resulted in a slight increase in strength to 76 MPa. On the other hand, after air quenching, the slow cooling rate caused that the strength of the samples remained at 448 MPa even at the temperature as high as 1150 °C. However, at 1300 °C, the sharp rise in Al2O3 levels on the surface precipitated the stratification of oxide layer, which, in turn, led to the significant decrease in strength to 158 MPa. Performance at high temperatures highlighted the excellent thermal shock resistance exhibited by Cr2AlC ceramic.

Facial synthesis of Cu@Ag core-shell particles through temperature gradient method with excellent oxidation resistance

To improve the oxidation resistance of Cu particles, the temperature gradient method is used to prepare Cu@Ag core-shell particles (TG-Cu@AgCSPs) with uniform particle size and enhanced oxidation resistance. The TG-Cu@AgCSPs are spherical, with an average size of 2.9 [Formula: see text] m, and the average thickness of the Ag shells is 280 nm. The morphological analysis and thermogravimetric results show that the TG-Cu@AgCSPs possess denser Ag shells and better oxidation resistance compared to core-shell particles prepared by the thermostatic method. The thermal oxidation behavior of TG-Cu@AgCSPs is investigated by heating in air. When heated below 300[Formula: see text]C, the Ag shells can keep intact morphology and protect the Cu cores from oxidation. Whereas the original Cu particles will be oxidized at 150[Formula: see text]C. In addition, the TG-Cu@AgCSPs are prepared as low-temperature conductive pastes to investigate their electrical properties. Compared with commercial Cu@Ag core-shell particles, the TG-Cu@AgCSPs possess more outstanding performance advantages and have the potential for commercial applications.

Durability of heat-treated Paulownia tomentosa and Pinus koraiensis woods in palm oil and air against brown- and white-rot fungi

This study aimed to evaluate and compare the effects of oil- and air-heat treatments on the durability of Paulownia tomentosa and Pinus koraiensis woods against Fomitopsis palustris and Trametes versicolor. The wood samples were treated in palm oil and air at 180, 200, and 220 °C for 2 h. The weight loss, morphology, crystalline properties, and chemical compounds of untreated and heat-treated wood after fungal attack were investigated. The significant difference in weight loss between oil- and air-heat-treated samples was shown at 220 °C. Heat-treated wood exposed to white-rot fungus showed a lower weight loss than that exposed to brown-rot fungus. The cell components in the untreated- and heat-treated Paulownia tomentosa and Pinus koraiensis at 180 °C were severely damaged due to fungal exposure compared to those at 220 °C. A fungal effect on the relative crystallinity was observed in heat-treated wood at 180 °C, whereas the effect was not observed at 220 °C. Following brown-rot fungus exposure, untreated- and heat-treated wood at 180 °C showed a notable change in the Fourier transform infrared (FTIR) peaks of polysaccharides, whereas no noticeable change in lignin peaks was observed. Heat-treated wood at 220 °C showed no noticeable change in the FTIR spectra owing to brown-rot fungus exposure. Exposure to white-rot fungus did not noticeably change the FTIR spectra of untreated and heat-treated wood.

High temperature AlN thin film ultrasonic transducers with dual mode wave excitation

AlN thin film ultrasonic transducers with dual mode wave (transverse and longitudinal) excitation were deposited by reactive RF magnetron sputtering technique. The transducers deposited at radial distances of 0 and 50 mm in the sample plane exhibited well-developed straight and inclined columnar structures with dominating (002) and (103) X-ray diffraction peaks, respectively. The transducers deposited at radial distances of 0, 30, and 50 mm demonstrated excitation of longitudinal, transverse, and longitudinal-transverse waves, respectively. Short term heat treatment was conducted in air within a temperature range of 20–900 °C to investigate the high temperature ultrasonic response. Temperature dependencies of the time-of-flight and pulse-echo amplitude were analyzed. Long term heat treatment in air at 700 °C for 192 h revealed a degradation of ultrasonic response due to the oxidation of the AlN layer.

Corrosion and isothermal interdiffusion properties of Ni–Al coatings under simulated biomass combustion conditions

The main issue with using biomass fuels in power plants is fireside corrosion. Applying corrosion-resistant coatings is one potential choice. The current study examines how a Ni–Al diffusion coating on austenitic stainless steel reacts to corrosion and interdiffusion (TP347H). Nickel was electrolytically deposited to create Ni–Al coatings, which were then pack aluminized at 650 °C. With an internal layer of Ni and a Ni2Al3 outer layer, a homogenous and dense Ni–Al coating was created. Samples were heated to 560 °C for 168 h in an environment designed to simulate the combustion of biomass. A localized corrosion attack was the result. By using isothermal heat treatment in static air at 650 °C or 700 °C for up to 3000 h, interdiffusion was examined. In the course of the interdiffusion process, the Ni2Al3 eventually changed into NiAl and Ni3Al. At both temperatures, porosity formed at the intersection of the Ni–Al coating and the Ni layer and grew with time.

Application of the Single-Stage Process of Dark Fermentation and Microbial Electrolysis to Improve Hydrogen Productivity from Water Hyacinth

The production of hydrogen (H2) from water hyacinth (WH) can contribute to reducing both the negative impact of WH on ecosystems and dependence on fossil fuels. In this study, the combination of dark fermentation (DF) and microbial electrolysis cell (MEC) in a single reactor, namely, sDFMEC, was investigated to improve the H2 productivity of WH. Furthermore, the intermittently applied voltage (I-Eapp) scheme and various methane (CH4) inhibition methods, including air exposure, heat treatment, and chloroform (CHCl3) addition, were applied for performance enhancement purposes. The findings indicated that with a sufficient duty time of external energy input (less than 1 hour), the intermittent mode can enhance the performance of WH-fed sDFMEC but does not significantly inhibit CH4 formation. While air exposure and heat treatment damaged both methanogens and exoelectrogens, lowering sDFMEC performance, additional CHCl3 showed the best selective and long-term inhibition on methanogens (over 350 operation hours without further addition). Overall, the combination of the I-Eapp scheme and CHCl3 applied in WH-fed sDFMEC achieved a yield of 670.1 ± 15.2   mL − H 2 / g − VS , around 160% higher than the normal condition.

Crosslinking through acyl hydrazone formation by reacting water soluble polyurethanes derived from ketone diol comonomers and those containing hydrazide pendant groups

Fully water-based formulations are gaining traction with the sustainability initiative for various applications. In this regard, producing the components required for making these formulations by eliminating toxic reagents is highly desirable. Hydrazone formation is widely used as a non-hazardous curing process in coating applications. Generally, carbonyl compounds that are used in the hydrazone forming reaction are nearly exclusively derived from vinyl polymers. This article describes a facile process for making carbonyl group containing diols and keto group containing water-soluble polymers therefrom by step growth or condensation polymerization. A water-soluble polymeric hydrazide was prepared by DCC coupling reaction between hydrazine hydrate and a polyurethane bearing pendant carboxylic acid group. The aqueous solutions of keto group containing, and hydrazide pendant polymers were mixed and coated on glass slides. Subsequently, the acyl hydrazone formation was studied under static heating in a hot air oven and a dynamic condition provided by blowing air under ambient conditions with a hair dryer. The dynamic nature of the latter process more than compensated the absence of direct heating to induce drying and hydrazone formation sequentially as studied by FT-IR spectroscopy. The cured slides were stable to water and were sensitive to weakly acidic aqueous solutions (about pH 3) formed by dissolving citric acid in water. The keto group containing diols enabled the hydrazone formation in polymer pairs entirely derived from step growth polymerization. As step growth or condensation polymers potentially offer both degradability and recycling through the cleavage of labile bonds prevailing in the polymer backbone, these keto group containing diols are preferable alternatives to keto group containing vinyl monomers commonly used for making hydrazones.

Achieving superhydrophobicity of Zr-based metallic glass surface with anti-corrosion and anti-icing properties by nanosecond laser ablation and subsequent heat treatment

Water repellency of superhydrophobic surfaces offers an opportunity to enhance the corrosion and icing resistance of metallic glasses (MGs). Inspired by the “lotus effect” in nature, hierarchical micro/nanostructures were constructed on a Zr-based MG surface using nanosecond laser ablation. By subsequent heat treatment in air, the structured surface showed a water contact angle (CA) of 168.2 ± 1.5° and a sliding angle (SA) of 4 ± 0.7° (adhesion force of 9.8 ± 1.7 μN), exhibiting repellency and low adhesion to water. Specifically, the superhydrophobic surface stored in air and immersed in water possessed stability and durability, and the superhydrophobic surface still maintained superhydrophobicity after mechanical scratching. The heat treatment temperature worked as a switch for controlling the wettability transition, and by tuning the temperature, the structured surface can switch from superhydrophobicity (CA: 168.2 ± 1.5°) to superhydrophilicity (CA: ~0°). Furthermore, compared to the polished MG surface, the superhydrophobic surface increased the corrosion resistance and freezing time, and delayed the freezing temperature. This study provides a facile non-fluorinated method for fabricating superhydrophobic MG surfaces with anti-corrosion and anti-icing properties, which would enhance the application of MGs as structural and functional materials under extreme conditions.

Investigation of the effect of the key pore size on the radon adsorption performance by combining grand canonical Monte Carlo and activated carbon modification experiments

Radon (Rn) is an important contributing factor to lung cancer. Activated carbon (AC) is currently the only Rn adsorbent for industrial applications. However, the effect of the key pore size of AC on Rn adsorption remains unclear, and enhancement of the Rn adsorption performance when using AC is still a challenge. In this work, grand canonical Monte Carlo (GCMC) simulations were performed to simulate the Rn adsorption ability of AC with different pore sizes. The adsorption selectivity of AC with pore sizes from 0.42 nm to 0.60 nm for Rn in the atmospheric environment was much greater than that for nitrogen and oxygen. The Rn adsorption performance was also investigated using KOH-modified activated carbon (KAC) with different pore sizes experimentally prepared using high-temperature roasting. The results showed that when the pore volume of KAC was significantly increased to approximately 0.55 nm, the Rn adsorption performance was obviously improved. Its adsorption coefficient reached 6.50 ± 0.11 m3 kg−1, which was 46.7 % higher than that of AC. After heating and regeneration in air, the Rn adsorption performance of KAC was basically unchanged. Combined with the comparative analysis using theoretical and experimental results, the relationship between the Rn adsorption performance of KAC and the pore volume at 0.55 nm is determined, and the accuracy of the GCMC calculation results was substantiated. This research provides a theoretical basis and an experimental method for improving the Rn adsorption performance of AC.

Thermal stability, work function and Fermi level analysis of 2D multi-layered hexagonal boron nitride films

Thermal stability and Fermi level analysis of commercial multilayer (ML) and as-grown 10 nm thick hexagonal boron nitride (hBN) films on Cu foil by atmospheric chemical vapor deposition (APCVD) by heating in N2 and air at temperatures ≤900 °C are studied. For all samples, progressive surface oxidation was observed correlating with higher hBN nucleation density. Thermal stability was measured in air from 200 °C to 400 °C (relative humidity ∼65%) where commercial ML and APCVD material degraded; BN peaks begin to be replaced by BO peaks at temperatures >300 °C. It is shown that hBN thermal stability is sensitive to Tgrowth and Cu foil surface preparation methods such as electropolishing (EP). We evaluate as-grown material for different Tgrowth conditions (1000 °C, 1030 °C, 1050 °C and 1060 °C) by ultraviolet photoelectron spectroscopy (UPS) to locate and understand subsequent Fermi level and work function variation, confirming our material is in general n-type, which becomes increasingly so as thermal stability regresses. To this effect, we observe a work function increase of 0.45 eV as BO increases with in-situ anneal temperature. An average electron affinity of 2.13 eV and 1.7 eV is determined for commercial hBN and APCVD material, respectively. Further work is required by material scientists to optimize the material properties of CVD hBN.

Combustion and flue gas evolution characteristics of rice husk in various mixtures and layers with Al2O3 particles and char prepared with different pyrolysis parameters

During pyrolysis and combustion experiments, rice husk and Al2O3 were combined in two ways, namely blending (rice husk was blended with Al2O3) and covering (rice husk was covered by Al2O3) modes, respectively. Rice husk biomass (RHB) char was prepared under different pyrolysis conditions. The resulting combustion characteristics and corresponding gaseous evolution of the biochar were compared. The maximum combustion rate decreased as particles accumulated, causing a shift in the thermo-gravimetric curve to higher temperature ranges. The combustion reaction was hindered in the covering mode. The combustion reactivity of the prepared char decreased as the char preparation time increased. During the char oxidation process, the release amounts of H2O and CO2 from char combustion increased first and then decreased, while the release amounts of CO, CH4, and organic components containing C=O gradually decreased with increasing char preparation time. Char prepared with the covering mode exhibited higher burn-out rates and combustion indices but lower activation energies required for combustion reaction. Additionally, the covering mode delayed the timely release of gases from the biomass heating in air, and the quantity of combustion gas released from the char produced at covering mode was greater than that released from the char produced at blending mode. The results obtained can improve the understanding of stacked biomass particles combustion process.

Synthesis of amorphous titania nanostructures by pulsed-laser decomposition of liquid metal-organic precursor with post-annealing transformation into crystalline-layered TiO2 nanorods and nanospheres

Amorphous and non-stoichiometric titania nanoparticles and films are produced by pulsed-laser decomposition of a liquid titanium tetra-isopropoxide (TTIP) precursor bath. Nanoparticles are formed in the TTIP solution, where the submerged laser-induced plasma generates vaporized species that are rapidly quenched by the surrounding (chilled) liquid precursor. Additionally, relatively-dense films are formed on a glass substrate above the surface of the TTIP bath by vapor transport and condensation of pyrolyzed species. Interestingly, upon post-annealing at 400 °C (∼ 0.3 TM) in ambient air of the collected nanoparticles in the bath, a transformation of the amorphous non-stoichiometric titania nanoparticles occurs, producing novel anatase-TiO2 morphologies, such as crystalline-layered nanorods and onion-like nanospheres.Chemical analysis of the as-synthesized particles and films shows they are rich in oxygen and carbon relative to TiO2. As a result, an amorphous-to-crystalline phase transformation during heat treatment in air starts at the surfaces of the nanoparticles, irrespective of their morphologies, and propagates into the interior. During annealing, the in-situ reaction of trapped-in species likely yields gaseous products (e.g., CO, CH4, H2O) that diffuse out of the particles, leaving sufficient Ti and O to enable crystallization of anatase-TiO2.Preliminarily, enhanced photocatalytic activity is found for the novel TiO2 nanostructures for hydrogen production from water reduction with methanol as a sacrificial agent. Decreased band-gap energy and increased absorbance in both the high-energy (i.e., 200 nm – 250 nm) and low-energy (i.e., 340 nm – 440 nm) UV regions are measured compared to that of commercial anatase.

Effect of Oxidative Synthesis Conditions on the Performance of Single-Crystalline LiMn2- x Mx O4 (M = Al, Fe, and Ni) Spinel Cathodes in Lithium-Ion Batteries.

LiMn2 O4 (LMO) spinel cathode materials attract much interest due to the low price of manganese and high power density for lithium-ion batteries. However, the LMO cathodes suffer from the Mn dissolution problem at particle surfaces, which accelerates capacity fade. Herein, the authors report that the oxidative synthesis condition is a key factor in the cell performance of single-crystalline LiMn2- x Mx O4 (0.03 ≤ x ≤ 0.1, M = Al, Fe, and Ni) cathode materials prepared at 1000 °C. The use of oxygen flow during the spinel-phase formation minimizes the presence of oxygen vacancies generated at 1000 °C, thereby yielding a stoichiometrically doped LMO product; otherwise, the spinel cathode prepared in atmospheric air readily loses capacity due to the oxygen vacancies in the structure. As a way of circumventing the use of oxygen flow, a one-pot, two-step heating in air at 1000 °C and subsequently at 600 °C is used to yield the stoichiometric LMO product. The lithiation heating at 1000-600 ⁰C resulted in a significant improvement in the cycling stability of the prepared LMO cathode in graphite-based full cells. This study on oxidative synthesis conditions also confirms the advantage of minimizing the surface area of the cathode particles.

Formation of a ceramic structure of promoted iron oxide catalyst

The paper concerns with the mechanism of the promoters influence on the ceramic structure of the iron oxide catalyst for the dehydrogenation of olefin and alkylaromatic hydrocarbons. The research shows the dynamics of changes in the porous structure of alloyed and unalloyed catalysts as a result of heat treatment in air at several temperatures significantly exceeding the operating temperature. Moreover, the paper presents data on the mechanical strength of alloyed and unalloyed model catalysts. Indeed, the particles are sintered to each other at the contact points of the globules forming a mechanically strong and thermally stable framework. However, the particles are sintered to each other at the contact points of the globules forming. Supposedly, potassium performs the function of a kind of flux. It lowers the temperature of the melting phase formation, which ensures a strong sintering of the ceramic material (catalyst) particles to each other. Hereby, there is a formation of a stable framework without a noticeable reduction of the catalyst working surface. The addition of zirconium oxide as an alloying agent provides an increase in the depth and degree of annealing of imperfections during the restructuring of the catalyst structure. Additionally, it provides the redistribution of the released energy. This assumption is confirmed by increasing of the alloyed catalyst granules mechanical strength. The results of research can be used for development and modification of iron-oxide catalysts for dehydrogenation of olefinic and alkylaromatic hydrocarbons.