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The Sm-doped MeWO sub(4) (Me = Ba, Sr, Ca, and Mg) phosphors were synthesized with a sol-gel method and studied for their microstructures and photoluminescence efficiencies. The hosts of the phosphors show very weak blue emissions except for the MgWO sub(4). The Sm super(3+) cation in the all hosts shows red emissions. Significantly, the photoluminescence efficiency of Sm super(3+) in CaWO sub(4) and BaWO sub(4) was largest as the calcination temperature equals 600 and 700 degree C, respectively. The BaWO sub(4) may be a new potential host of rare earth-doped phosphors.

LiFePO sub(4)/C/Ag composite hollow nanofibers were synthesized by calcination of the coaxial electrospun nanofibers with polyvinyl pyrrolidone (PVP) as core and [LiOH + Fe(NO sub(3)) sub(3) + H sub(3)PO sub(4)]/PVP/AgNO sub(3) as shell. PVP was used as the electrospinning template and carbon source. During the calcination, LiFePO sub(4) precursor was transformed to LiFePO sub(4) while AgNO sub(3) and PVP were decomposed into silver and carbon. The morphology and properties of the as-prepared samples were characterized by X-ray diffraction, scanning electron microscopy, BET specific surface area analysis, electrochemical impedance spectroscopy and galvanostatic charge-discharge measurements. The results indicate that the mean diameter of as-prepared LiFePO sub(4)/C/Ag composite hollow nanofibers is 154.5 plus or minus 18.6 nm and the BET specific surface area is 119.14 m super(2) g super(-1). The addition of silver and carbon does not affect the structure of LiFePO sub(4), but improves its electrochemical performances. At the current density of 0.2 C, the initial discharge capacity of LiFePO sub(4)/C/Ag hollow nanofibers electrode is 138.71 mAh g super(-1), which is higher than that of LiFePO sub(4)/C nanofibers electrode. The improved specific capacity may be attributed to increase electrode conductivity after the introduction of silver. The formation mechanism of the LiFePO sub(4)/C/Ag composite hollow nanofibers was also proposed.

Li0.25Sr0.5(MoO4):Eu0.253+ red-emitting phosphors were prepared by the organic gel-thermal decomposition process with metal salts and citric acid as starting reagents. X-ray diffraction, scanning electron microscopy and photoluminescent spectroscopy were used to characterize the as-prepared phosphors. The Li0.25Sr0.5(MoO4):Eu0.253+ phase consisting of nanosized crystallites is formed at 400 degree C and the nanosized crystallites with a tetragonal-dipyramid morphology increase with the calcination temperature and time. During the early period at 650 degree C, the microstructure of the Li0.25Sr0.5(MoO4):Eu0.253+ crystallites are unstable and the re-crystallization for some particles takes place with a particle morphological modification. The optimized calcination conditions for the Li0.25Sr0.5(MoO4):Eu0.253+ phosphors are 650 degree C for 13 h. The Li0.25Sr0.5(MoO4):Eu0.253+ phosphors with particle sizes about 0.5 to 2.0 Delta *mm obtained under the optimized conditions can be excited by the ultraviolet light 395 nm and blue light 466 nm, which are well met with the requirements for the current commercial near-UV and blue LEDs, and exhibit a high emission performance.

In nickel laterite agglomerates from rotary kiln of RKEF process the phases lizardite and/or chrysotile, clinochlore, quartz and hematite were identified. The product contain SiO2 (32.67%), Fe2O3 (24.68%), MgO (21.81%) and NiO (3.30%) as principal components. When thermal treatment were carried out weight differences can be observed where the adsorbed water removed during drying, without phase changes in temperatures ranging from 60°C to 100°C, indicated influence of mineral assemblage. Phase changes and weight loss was observed in calcination with clear crystalline restructuring of the serpentines and clinochlore at 500°C. Above this temperature new phases are crystallized until 820°C, when is formed forsterite and enstatite, provably trevorite and remaining unchanged quartz. There were identified nickel minerals. The nickel occurs in bearing phases as Mg-Ni ion substitution in the crystal structure. On the analyzed conditions might infer that these new phases formed can affect the pyrometallurgical process of reduction.

In order to impart the properties of cementitious material to the Tibetan Agar soil, two high-temperature activation mechanisms (HTMA, HTMB) were designed in this study, and the products and hydration-hardening properties of Tibetan Agar soil high-temperature activation mechanism were analyzed by means of SEM, XRD, and XRF. The results show that the main components of Tibetan Aga soil are calcite and quartz; Aga soil is activated by HTMA high-temperature activation, forming the main products of CaO, C2S, CaSiO3, and CaAl2Si2O8, and its products have both air-hardening and water-hardening characteristics; Aga soil is activated by HTMB high-temperature activation, and when the temperature reaches 1250 °C when the clinker is not found in the CaO, the generation of C2S, C3S, C3A, C4AF, and Mg2SiO4 minerals with good water-hardening cementitious properties occurs when the temperature rises to 1350 °C, although the formation of some inert minerals that do not have the cementitious properties, but this temperature activation products of the thermodynamic properties of the best; Enhancing the value of lime saturation degree (KH) and silicon rate (SM) can promote the formation of the products of the C2S and C3S, increase the reactivity of the Aga soil activation products, and increase the hydration heat as well as compressive and flexural strength, combined with the results of the hydration heat and mechanical test, KH is recommended to be 0.9~0.94, SM is recommended to be 1.8~2.4, and alumina ratio (IM) is recommended to be 1.8~2.4 when Aga soil is used with raw materials.

In this work are presented analyzes from calcination and sintering of zinc niobate ceramics by microwave processing. In order to obtain minimum processing parameters, the behavior of the material was first studied for the calcination at different temperatures in the range of 450 to 1150°C, with duration time of 10 minutes. The sintering was carried out between 950 and 1050°C. The results showed that the crystalline structure of the calcined and sintered samples was influenced by the temperature, because, according to the increase in temperature, the evolution of the formed crystalline phases was observed and only the Zn3Nb2O8 and ZnNb2O6 phases prevailed in the final microstructure. The densification of the sintered ceramics was influenced by the time and temperature of the heat treatment, with lower residual porosity and grain growth with the increase of the sintering temperature in the microwave oven.

 This research evaluated powdered nepheline syenite (NS) as a potassium source for corn. The treatments were different particle sizes and heating the NS with calcium chloride at 900oC, and the samples were incubated in soil under controlled conditions before cropping. The experiment was conducted in a greenhouse using corn (Zea mays L.) plants cultivated in pots in a completely randomized 2x3 + 2 factorial block design with five replications. Five plants were growth in each pot with 5 kg of an Oxisol–Typic Hapludox soil for three successive 33-day cropping periods. At the end of each cropping period the K contents of shoot dry matter and soil and were determined. There was no effect on shoot dry matter production (p> 0.05). There was greater soil and dry matter K contents when heated NS was used, but for particle size. The treatments significantly affected (p <0.01) the K levels in the plants in the first crop. There was no residual effect on potassium content in the soil after the third crop (p> 0.05). NS in natura has low solubility and does not provide potassium to plants while calcined rock powder works as a thermopotassium source.

The aim of this study was to explore the antibacterial and antioxidant efficacy of nickel oxide nanoparticles (NiO NPs). The Raphanus sativus ( R. sativus ) extract mediated NiO NPs were calcined at 100, 300, 600 and 900 ℃ in a muffle furnace for 3 h. The increased intensity of diffraction bands in the X-ray diffraction (XRD) spectrum suggest that the degree of crystallinity increases with increasing calcination temperature. The desired elements was depicted in the energy dispersive X-rays (EDX) spectrum confirm the purity of the NiO Sample. The variation in surface morphology and increase in the particles size from 12.78 to 51.42nm was determined from the transmission electron microscope (TEM) micrographs. The shift toward higher wavelength was observed in the diffuse reflectance spectroscopy (DRS) spectra with increasing calcination temperature, results into a clear decrease in band gap from 3.12 to 2.86 eV. The presence of hydroxyl group along with other organic moieties were confirm through Fourier transform infrared (FTIR) spectroscopy analysis. The biological potential of the calcined NiO NPs was examined during the antibacterial and antioxidant experiments. The antibacterial effect of NiO NPs was studied using the agar well diffusion process, and the ABTS free radical scavenging potential of NiO NPs was also assessed. The activity of NiO NPs calcined at 100 °C is greater than that of those calcined at higher temperatures.

Background: Nickel stannate nanocomposites could be useful for removing organic and toxic water pollutants, such as methyl orange (MO). Aim: The synthesis of a nickel oxide–tin oxide nanocomposite (NiO-SnO2 NC) via a facile and economically viable approach using a leaf extract from Ficus elastica for the photocatalytic degradation of MO. Methods: The phase composition, crystallinity, and purity were examined by X-ray diffraction (XRD). The particles’ morphology was studied using scanning electron microscopy (SEM). The elemental analysis and colored mapping were carried out via energy dispersive X-ray (EDX). The functional groups were identified by Fourier transform infrared spectroscopy (FTIR). UV–visible diffuse reflectance spectroscopy (UV–vis DRS) was used to study the optical properties such as the absorption edges and energy band gap, an important feature of semiconductors to determine photocatalytic applications. The photocatalytic activity of the NiO-SnO2 NC was evaluated by monitoring the degradation of MO in aqueous solution under irradiation with full light spectrum. The effects of calcination temperature, pH, initial MO concentration, and catalyst dose were all assessed to understand and optimize the physicochemical and photocatalytic properties of NiO-SnO2 NC. Results: NiO-SnO2 NC was successfully synthesized via a biological route using F. elastica leaf extract. XRD showed rhombohedral NiO and tetragonal SnO2 nanostructures and the amorphous nature of NiO-SnO2 NC. Its degree of crystallinity, crystallite size, and stability increased with increased calcination temperature. SEM depicted significant morphological changes with elevating calcination temperatures, which are attributed to the phase conversion from amorphous to crystalline. The elemental analysis and colored mapping show the formation of highly pure NiO-SnO2 NC. FTIR revealed a decrease in OH, and the ratio of oxygen vacancies at the surface of the NC can be explained by a loss of its hydrophilicity at increased temperatures. All the NC samples displayed significant absorption in the visible region, and a blue shift is seen and the energy band gap decreases when increasing the calcination temperatures due to the dehydration and formation of compacted large particles. NiO-SnO2 NC degrades MO, and the photocatalytic performance decreased with increasing calcination temperature due to an increase in the crystallite size of the NC. The optimal conditions for the efficient NC-mediated photocatalysis of MO are 100 °C, 20 mg catalyst, 50 ppm MO, and pH 6. Conclusions: The auspicious performance of the NiO-SnO2 NCs may open a new avenue for the development of semiconducting p–n heterojunction catalysts as promising structures for removing undesirable organic pollutants from the environment.

The in-plane and edge sulfur vacancies (Sv) of MoS2 serve as the active sites of CH3OH and CH4 in CO2 hydrogenation, respectively. However, edge sulfur vacancies are easily exposed, making it highly significant to inhibit their quantity and effectively promote methanol synthesis. In this study, we reported that MoS2/MoO2, obtained via calcination without metal doping or complex synthesis methods, undergoes structural rearrangement and active site regulation of MoS2. This modification not only significantly enhances the CO2 conversion rate but also sharply reduces the sulfur vacancies at the edges of MoS2, enabling targeted control over CH3OH and CH4 selectivity. Compared to pure MoS2, CO2 conversion increased from 8.9 ​% to 13.5 ​%, while CH3OH selectivity rose dramatically from 2.5 ​% to 66.0 ​%. In-situ DRIFTS and DFT calculations demonstrate that CO2 dissociates more readily at the edge oxygen vacancies of MoS2/MoO2, encountering a lower energy barrier, which accounts for the improved CO2 conversion. The surface-bound CO∗ intermediates are formed and subsequently hydrogenated to species such as HCO∗. The formed CH3OH desorbs from the catalyst surface with lower energy, resulting in higher CH3OH selectivity. The catalyst exhibits excellent stability over 500 ​h and shows promising potential for industrial applications. This study provides theoretical insights and a novel research paradigm for designing highly active and selective Mo-based chalcogenide/oxide composites. It holds significant practical value for advancing the “double carbon” goal and facilitating energy structure transformation.