Ti-Zr-Hf-Nb-Ta compositionally complex ceramics were prepared using various synthesis and sintering routes to investigate their impact on electrical conductivity. Two processing strategies were employed: (i) pellets prepared from raw powders and subsequently sintered, and (ii) pellets prepared from calcined powders and subsequently sintered. All samples exhibit thermally activated conductivity, indicating semiconducting behaviour. The samples from calcined powders show direct-current (DC) conductivities one to two orders of magnitude higher than those prepared from raw powders, together with lower activation energies which can be attributed to a difference in pellets’ microstructure arising from variations in precursor decomposition, phase evolution, and grain growth. Within the series of samples prepared from raw powders, the hydrothermally prepared powder yields conductivities comparable to those of samples prepared from calcined powders. These observations suggest that powder characteristics and microstructural features may influence charge transport. Comparison with recent literature places the electrical properties of Ti-Zr-Hf-Nb-Ta oxide ceramics within the typical range for multicomponent mixed oxides, indicating potential for application in solid oxide fuel cell components and related electrochemical devices.

This study investigates the magnetic properties of strontium-doped lanthanum manganites [La1−xSrxMnO3 (LSMO)], focusing on the effects of doping and synthesis methods. Materials with different Sr-doping concentrations (x = 0, 0.1, 0.2, and 0.3) were prepared by citrate–nitrate autocombustion (CNA) and coprecipitation synthesis. Magnetization curves exhibit a transition from paramagnetic behavior to long-range ferromagnetic order below Curie temperatures (TC), which increase with Sr content due to Jahn–Teller distortions and electron delocalization. The synthesis method significantly influences magnetic properties, with CNA-prepared samples exhibiting a systematic decrease in coercivity and remanence with Sr doping, leading to very soft ferromagnetic behavior at x = 0.3. In contrast, coprecipitation-synthesized materials show deviations due to variable oxygen content, which affects Mn valence states and magnetic interactions. Hysteresis loops and magnetocaloric effects were also investigated, revealing that coprecipitation-derived samples exhibit a higher magnetocaloric effect due to structural defects and oxygen nonstoichiometry. A comparison with gadolinium and previous studies highlights the potential of LSMO materials for magnetic refrigeration applications despite their somewhat lower magnetic entropy changes.

The aim of this study was to prepare and characterize thin hybrid films on polyurethane-coated knitted fabrics and to achieve satisfactory color fastness to artificial light. Sol–gel-derived hybrid thin films were deposited via the dip-coating of 3-glycidoxypropiltrimethoxysilane. Titanium dioxide (TiO2) and zinc oxide (ZnO) nanopowders were added to compensate for the insufficient aging resistance, which manifests itself in low color fastness and is one of the most frequent complaints from manufacturers of coated marine fabrics (yachts, boats, etc.). The optimum processing conditions were determined by varying the concentration of precursors and auxiliaries, the mass concentration of TiO2 and ZnO nanopowders, the drawing speed, and the methods and process of fabric treatment. The hybrid films were also characterized using scanning electron microscopy and Fourier transform infrared spectroscopy with attenuated total internal reflection, while Spectraflash SF 300 investigated color fastness. After 300 h of exposure in a xenon chamber, the thin hybrid films showed good color fastness and good resistance to washing cycles. The sol–gel treatment proved to be a successful answer to the manufacturers’ need for the post-treatment of polyurethane-coated knitted fabrics against UV radiation for use in the marine sector (yachts, speedboats, etc.).

The influence of A-site cation doping, crystal structure and structural defects (oxygen nonstoichiometry) on the electrical conductivity of Sr-doped CaMnO3 (CSMO) and BaMnO3 (BSMO) was investigated. CSMO and BSMO were prepared by citrate-nitrate autocombustion and coprecipitation synthesis, pressed into pellets and sintered. Since the oxygen nonstoichiometry in CSMO was uniform, the increase in electrical conductivity was primarily caused by the increase in Sr content. On the other hand, the oxygen nonstoichiometry in BSMO was more pronounced and it decreased with Sr-doping. Therefore, the highest conductivities were obtained for the undoped BaMnO3 samples. The electrical conductivities of CSMO were similar to those of widely investigated rare-earth manganites and more than 104 times higher than those of BSMO. Therefore, CSMO has the potential to be a low-cost cathode material in solid oxide fuel cells.

Industrial effluents containing dyes are a serious threat to the ecosystems and the removal of these dyes is most often conducted by adsorption. In this study, Sr-doped lanthanum (LSMO), calcium (CSMO) and barium (BSMO) manganites were prepared by the autocombustion and co-precipitation synthesis, and tested as the adsorbents for the removal of methyl orange (MO) as a model pollutant from the aqueous solution. The highest adsorption of the MO solution obtained by CSMO adsorbents was 83.5%, while the highest adsorption of 95% was achieved using LSMO and BSMO due to their large specific surface area and average pore diameter promoting the diffusion of the MO to the adsorbent surface. The oxygen nonstoichiometry of these materials also contributed to their adsorption properties due to the presence of unpaired electrons, which affected their electronic structure and lowered the adsorption energy. Kinetic studies showed that Ho’s pseudo-second-order model exhibited the best fit with the experimental data, indicating that chemisorption is the rate-limiting step. The rate constants were the highest for BSMO adsorbents ranging from 3.35 to 3.50 × 10 –2 g mg –1 ·min –1 . The adsorbents can be fully regenerated by calcining at 700°C for 2 h with no loss of their activity.

Thermal analysis methods are widely used in the characterization of substances and materials in chemistry and engineering. But they also find their application in life sciences: biology and medicine. This paper exhaustively and critically reviews the application of the most commonly used thermal analysis methods for the characterization of organs and tissues of plants, animals, and humans. The methods are suitable for differentiating between several types of water in a cell, optimizing treatment, storage, or cultivation conditions, following plant or animal development, medical diagnostics and modelling, and more. Expertise developed in the characterization of synthetic materials and molecules can be transferred to that of biological tissues and biomolecules and opens a perspective for interdisciplinary research. Still, researchers should take into consideration the inherent complexity of biological samples, as well as inevitable changes when isolating the tissue from the living organism.

Inorganic perovskite CaMnO3 was proposed as a substitution for the TiO2 anatase in electron transport layers of solar cells containing the hybrid perovskite CH3NH3 PbI3 based on increased mobility of electrons and better optical matching. Due to a suitable band gap concerning the absorption of sunlight, we investigate the potential of CaMnO3 and similar manganite perovskites, where Ca is replaced by either Sr, Ba or La, as an absorber layer in inorganic perovskite solar cells. In this study, we have used optical measurements on the synthesized AMnO3 (A=Ca, Sr, Ba, La) samples to aid density functional theory calculations (DFT) in order to accurately simulate the electronic and optical properties of AMnO(3) compounds and gauge their potential for the role of absorber layer. Both experimental measurements and theoretical calculations show suitable band gap of 1.1-1.5 eV, depending on the compound, and absorption coefficients of the order of 10(5) cm(-1) in the visible part of the spectrum.

Sr-doped CaMnO3 and BaMnO3 were prepared by autocombustion (CNA) and coprecipitation and investigated as catalysts for catalytic oxidation of benzene, toluene, ethylbenzene and o-xylene mixture in a fixed-bed reactor. Ethylbenzene and o-xylene were completely removed by all prepared catalysts. Toluene was completely removed by BaMnO3 and Ba0.5Sr0.5MnO3 catalysts prepared by CNA synthesis, while conversions of similar to 98% or higher were obtained for all the other prepared catalysts. The highest benzene conversion of 86.43% at 723 K was obtained for the Ba0.7Sr0.3MnO3 catalyst prepared by CNA synthesis. The differences in catalytic activities can be ascribed to Sr-doping, oxygen nonstoichiometry and morphological differences.

SrMnO3 thin films were successfully prepared by spin coating the viscous solution obtained from the au-tocombustion synthesis. To ensure the transformation of the precursor solution into the manganite phase, conventional thermal treatment and novel phototreatment were applied. The thermal treatment resulted in stable hexagonal SrMnO3, while phototreatment yielded cubic SrMnO3 phase which is usually not stable at ambient conditions. The optical properties of the prepared materials were measured revealing the optical gaps of 1.5 eV for thermally treated material and about 1.3 - 1.4 eV for the phototreated samples. Comparison with ab initio result shows a higher theoretical value of 1.9 eV, ascribed to high exciton binding energy. Since these values are similar to the optical gap (1.48 eV) of widely studied formamidium lead iodide thin films, SrMnO3 thin films are promising candidates for active layers in inorganic perovskite solar cells.(c) 2023 Elsevier B.V. All rights reserved.

Perovskiti su tema brojnih znanstvenih istraživanja zbog svojih primjenskih svojstava, kao što su električna vodljivost, feromagnetičnost i reduktivnost. Svojstva perovskita dodatno se mogu poboljšati dopiranjem te formiranjem strukturnih defekata. Cilj ovog rada bio je istražiti mogućnost pripreme stroncijem dopiranog lantanova manganita kemijske formule La0,5Sr0,5MnO3 postupkom koprecipitacije. Dio materijala žaren je na 1200 °C/2h, a dio je prešan u tabletu i sinteriran na istim uvjetima. Iako je rendgenska difrakcijska (PXRD) analiza žarenog praha ukazivala na nastanak čiste faze, morfološkom analizom lomne površine tablete uočene su dvije faze. Energijski razlučujuća rendgenska spektrometrija pokazala je da je svjetlija faza SrMnO3, dok je tamnija La0,76Sr0,24MnO3. Tableta je usitnjena te analizirana PXRD-om. Iako su se maksimumi poklapali sa standardnom rendgenskom karticom faze La0,5Sr0,5MnO3, Rietveldovom metodom utočnjavanja potvrđen je udio Sr od 0,24 i nastanak faze La0,76Sr0,24MnO3. Ostatak stroncija dodanog tijekom sinteze kristalizirao je u SrMnO3 fazu. Time je potvrđeno da je supstitucija moguća do određene mjere nakon koje postoji opasnost od izdvajanje nove faze, pogotovo ako je uzorak pripremljen u obliku tablete.

: Industrial and population growth is constantly increasing energy consumption. Since 81.3% of consumed energy is produced from fossil fuels, the high pollution and emission rates are leading to climate changes resulting in extreme weather conditions. The development of new materials and technology is necessary to achieve sustainable societal growth and development. In the field of new materials, perovskites are the main subject of much scientific research conducted in the last decade. Perovskites are usually divided into two groups: halides and oxides. The application of perovskite halides in photovoltaic and solar cells is already well-known and investigated. On the other hand, perovskite oxides do not possess optical and light-absorption properties comparable to perovskite halides, but they have promising electrical and magnetic properties and high reducibility rates. This review is dedicated to the perovskite oxides, preparation methods of this material and their application for energy transformation and storage applications. The perovskite oxides have high potential as working materials in solid oxide fuel cells (SOFC), Ca batteries, thermochemical energy storages (TCES) and ambient temperature magnetic refrigerators (MR).

Salt-affected and sandy pedospheres low in complex organic and mineral matrices critical for metal sorption (e.g. humics, aluminosilicates) could exacerbate metal transfer into the food chain. To test this hypothesis, a 3-factor study with salinity (0–50 mM NaCl), humates (HA; 0–150 mg/kg) and Cd contamination (0–9 mg/kg) was conducted in sandy substrate with strawberry. Cadmium phytoaccumulation decreased in the order roots > crowns > leaves > fruits. In comparison to the control, tissue Cd concentration was influenced by the NaCl × HA × Cd interaction, increasing Cd in leaves (up to 241-fold) and fruits (up to 135-fold) and exceeding the European maximum limit of 0.05 mg Cd/kg w wt. Surface analyses (XRD, SEM–EDX, FTIR, SIMS) revealed that the growth substrate rich in SiO2 (> 87% w/w) had uniform, nonporous and chemically unreactive surface structure. In contrast, the more complex HA matrix featuring abundant and heterogeneous micro-porosity and a large content of reactive radicals. Chemical speciation modelling of the rhizosphere solutions showed that almost all Cd was dissolved and distributed among the bioavailable Cd2+, Cl-complexed and HA-complexed pools, with small amounts of Cd adsorbed to K/Na-aluminosilicates. Slightly acidic pH (5.4–6.2) and complexation with Cl and HA in the rhizosphere favoured Cd solubility and its transfer to plants. The assessment of health risk of strawberry fruit consumption indicated a relatively higher the Estimated Daily Intake (EDI) in children (5% of provisional tolerable daily Cd intake) vs adults (< 1%), with the Dietary Risk Coefficient (DRC) < 0.1 in both populations, suggesting a low risk. However, given Cd intake from other sources and its cumulative effects, precautions are needed when consuming strawberries grown in salt-affected sandy soils.

Modern society is faced with an important challenge – how to ensure enough energy and resources for industrial and population growth and preserve the environment at the same time? The answer lies in the development of novel technologies based on eco-friendly and low-cost materials. In the field of new materials, perovskite oxides stand out due to their multiple properties contained in a single material. The most important are electrical, magnetic and catalytic properties which are the basis for their practical applications. Perovskites were widely investigated over the last 70 years, but perovskite-based technologies have still not reached commercialization. This review presents several novel perovskite-based technologies and addresses possible issues and opportunities for their implementation, based on the recent scientific discoveries.

The strontium-doped lanthanum manganites (La1-xSrxMnO3, LSMO) have potential use in devices for energy conversion and storage due to their chemical stability and high electrical conductivity. In this study, LSMO (x = 0, 0.1, 0.2, 0.3) were prepared by the citrate-nitrate autocombustion (CNA) and coprecipitation synthesis. The formation of the LSMO phase was confirmed by X-ray diffraction and the lattice parameters were determined by Rietveld refinement analysis. The oxygen nonstoichiometry in samples was determined by permanganate titration. The results of electrical conductivity measurement have shown semiconductor behaviuor in all samples, with conductivity rising with temperature and Sr-amount. Furthermore, it was observed that LSMO samples prepared by the coprecipitation method possess higher conductivity than samples prepared with the CNA method due to the higher oxygen nonstoichiometry. Electrical conductivities of all LSMO samples were in 10(-2)-0.45 Omega(-1) cm(-1) range, which is comparable to the conductivity of Si. (c) 2022 Elsevier B.V. All rights reserved.

The simple perovskite oxides, manganites, are nowadays subject of extensive research because of their electrical, magnetic and photocatalytic properties. In this paper, manganites described with general formula A1-xSrxMnO3 (A = Ca, Ba, La) were prepared by the coprecipitation method. Precursors and calcined powders were analyzed by Fourier transform infrared (FTIR) spectroscopy and crystallization was studied by X-ray diffraction. In all systems, successfully doped manganites were obtained by coprecipitation. Positions and shapes of carbonate bands in carbonate precursors FTIR spectra were shown to be useful for screening successful syntheses of doped manganites, particularly in Ca1-xSrxMnO3 and La1-xSrxMnO3 systems.

Strontium-doped lanthanum manganites, La1-xSrxMnO3 (LSMO), are promising and affordable catalysts for oxidative degradation of volatile organic compounds. LSMO catalysts (x = 0, .1, .2, and .3) were prepared by the citrate-nitrate autocombustion (CNA) and coprecipitation synthesis. The phase composition was confirmed by X-ray diffraction and Rietveld refinement analysis, while the oxygen content was determined by Mohr's salt permanganate titration. Morphology and porosity of prepared catalysts was correlated to catalytic oxidation of benzene, toluene, ethylbenzene and o-xylene. It was observed that both synthesis methods yielded catalysts of similar average pore size diameter and specific surface area, but the pore size distribution differed: CNA-prepared catalysts had a multimodal pore size distribution, while the coprecipitated ones had a single maximum at 4 nm. Catalysts prepared by the CNA method have shown a higher catalytic activity in the temperature range 373-723 K, as the presence of Mn3+/Mn4+ mixed valences increased their reducibility.

Tomato waste was studied as a low-cost biosorbent for the removal of five pharmaceuticals (dexamethasone, febantel, procaine, praziquantel, and tylosin) from water. Tomato waste was characterized chemically and microstructurally before and after simulated sorption. Sorption performance was interpreted as a function of the initial pharmaceuticals concentration, temperature, and physicochemical properties of the tomato waste. The linear, Freundlich, and Dubinin–Radushkevich (D-R) isotherms were used to describe the experimental results at different temperatures (298, 303, and 308 K). Thermodynamic parameters such as standard free energy (ΔG°), enthalpy change (ΔH°), and entropy change (ΔS°) were determined. Negative values of ΔG° in the temperature range of 298–308 K strongly indicate the spontaneous nature of the biosorption process. In addition, the values of ΔH° for the biosorption of dexamethasone, procaine, praziquantel, and tylosin on tomato waste were negative, indicating exothermic processes, while the positive value for febantel indicated an endothermic process. The kinetic data were analyzed using (i) kinetic models to determine the kinetic parameters (Lagergren’s pseudo-first order and Ho’s pseudo-second order) and (ii) adsorption–diffusion models to the describe transport mechanisms of pharmaceuticals from aqueous solution onto tomato waste as adsorbent (Weber–Morris intraparticle diffusion and Boyd film diffusion models).

Strontium and lanthanum manganites are nowadays the subject of extensive research because of their promising electrical and magnetic properties. Strontium manganite, SrMnO3, was successfully prepared by citrate-nitrate autocombustion (CNA) and by the coprecipitation method. These methods were then applied to synthesis of strontium doped lanthanum manganites, La1-xSrxMnO3 (x ​= ​0, 0.1, 0.2 and 0.3). The optimal phase formation conditions were determined by thermogravimetry and differential scanning calorimetry. Crystallization of precursors and calcined powders was studied by X-ray diffraction. Powders, in which pure manganite phase was obtained, were also analyzed by permanganate titration with Mohr's salt in order to determine oxygen nonstoichiometry. Oxygen stoichiometry was achieved in SrMnO3 powders obtained by the CNA method and calcined at 1000 ​°C as well as in powders obtained by the coprecipitation method and calcined at 1200 ​°C. La1-xSrxMnO3 phase was oxygen stoichiometric for x ​= ​0.3 while decreasing of x resulted in cation deficiency, i.e. oxygen excess. Oxygen deficit was achieved for x ​= ​0.09 upon calcination at 1200 ​°C. The obtained results were confirmed by thermogravimetry and the Rietveld refinement analysis.