Prewetting Induced Hydrophilicity to Augment Photocatalytic Activity of Nanocalcite @ Polyester Fabric

To eliminate imidacloprid insecticide from wastewater, nanocalcite was grafted onto the surface of pretreated polyester fabric. The process of seeding was followed by the low temperature hydrothermal method for the growth of nanocalcite for the functionalization of fabric. The goal of this study was to improve the hydrophilicity of the nanocalcite photocatalyst that had been grafted onto the surface of polyester fabric (PF) using acidic and basic prewetting techniques. The morphological characteristics, crystalline nature, surface charge density, functional groups of surface-modified nanocalcite @ PF were determined via SEM, XRD, FTIR, and Zeta potential (ZP), respectively. Characterization results critically disclosed surface roughness due to excessive induction of hydroxyl groups, rhombohedral crystal structure, and high charge density (0.721 mS/cm). Moreover, contact angle of nanocalcite @ PF was calculated to be 137.54° while after acidic and basic prewetting, it was reduced to 87.17° and 48.19°. Similarly, bandgap of the as fabricated nanocalcite was found to be 3.5 eV, while basic prewetted PF showed a reduction in band gap (2.9 eV). The solar photocatalytic mineralization of imidacloprid as a probe pollutant was used to assess the improvement in photocatalytic activity of nanocalcite @ PF after prewetting. Response surface methodology was used to statistically optimize the solar exposure time, concentration of the oxidant, and initial pH of the reaction mixture. Maximum solar photocatalytic degradation of the imidacloprid was achieved by basic prewetted nanocalcite @ PF (up to 91.49%), which was superior to acidic prewetted fabric and as-fabricated nanocalcite @ PF. Furthermore, HPLC and FTIR findings further indicated that imidacloprid was decomposed vastly to harmless species by basic prewetted nanocalcite @ PF.

Formation of Solid Solutions and Physicochemical Properties of the High-Entropy Ln1−xSrx(Co,Cr,Fe,Mn,Ni)O3−δ (Ln = La, Pr, Nd, Sm or Gd) Perovskites

Phase composition, crystal structure, and selected physicochemical properties of the high entropy Ln(Co,Cr,Fe,Mn,Ni)O3−δ (Ln = La, Pr, Gd, Nd, Sm) perovskites, as well as the possibility of Sr doping in Ln1−xSrx(Co,Cr,Fe,Mn,Ni)O3−δ series, are reported is this work. With the use of the Pechini method, all undoped compositions are successfully synthesized. The samples exhibit distorted, orthorhombic or rhombohedral crystal structure, and a linear correlation is observed between the ionic radius of Ln and the value of the quasi-cubic perovskite lattice constant. The oxides show moderate thermal expansion, with a lack of visible contribution from the chemical expansion effect. Temperature-dependent values of the total electrical conductivity are reported, and the observed behavior appears distinctive from that of non-high entropy transition metal-based perovskites, beyond the expectations based on the rule-of-mixtures. In terms of formation of solid solutions in Sr-doped Ln1−xSrx(Co,Cr,Fe,Mn,Ni)O3−δ materials, the results indicate a strong influence of the Ln radius, and while for La-based series the Sr solubility limit is at the level of xmax = 0.3, for the smaller Pr it is equal to just 0.1. In the case of Nd-, Sm- and Gd-based materials, even for the xSr = 0.1, the formation of secondary phases is observed on the SEM + EDS images.

Dielectric Properties of Cr3+ Doped Al2O3 of a Hierarchical Nanostructure Synthesized Using a Highly Porous Precursor of Tubular AlO(OH)⋅αH2O Fibers

Herein, we have developed a Cr3+ doped Al2O3 of a hierarchical nanostructure by a simple two-step synthesis. A pure AlO(OH)⋅αH2O, as synthesized in forms of small tubular fibers by hydrolysis of Al-metal sheets, is easily doped with selective Cr3+ dosages up to 2.0 mol% using an aqueous CrO3. As-synthesized samples exhibit XRD of a single phase Cr3+: Al2O3 of a rhombohedral crystal structure. Average pore-volume is decreased as 98.1, 89.8, and 61.5 cm3-g-1 in the 0.5, 1.0 and 2.0 % Cr% doped samples, with average pore radius of 1.70, 2.17 and 1.90 nm, respectively, as measure from BET specific surface area. Local Al-O vibrations exhibit IR bands of 400 to 1200 cm-1 intrinsic of oxygen polygons. At room temperature, a duly tailored dielectric permittivity of 480 is obtained in a 2.0 mol% Cr3+:Al2O3 and that is enhanced progressively on heating it over 25 to 300 °C, showing a value 6700 at 300 °C in phonon induced dynamics of charge carriers, useful for solid-state electronics.

Structural, Optical, Ferroelectric and Magnetic Properties of NiTiO3 Ceramic Synthesized by Citrate Gel Method

The NiTiO3 ceramic was synthesized in nanostructured form by citrate gel method. The phase structure, microstructure and magnetic properties of synthesized compounds were investigated by X-ray diffraction (XRD), scanning electron microscope and vibrating sample magnetometer. Williamson–Hall plot was used to calculate the crystallite size and microstrain of sample. The XRD analysis showed the formation of rhombohedral crystal structure of synthesized powders. The crystallite size is about 35[Formula: see text]nm and microstrain is [Formula: see text]. The optical band gap was estimated from UV-Visible spectrum with value of 2.43[Formula: see text]eV. The NiTiO3 samples showed coexistence of ferroelectric and antiferromagnetic properties at room temperature.

2D Bi2Se3 van der Waals Epitaxy on Mica for Optoelectronics Applications

Bi2Se3 possesses a two-dimensional layered rhombohedral crystal structure, where the quintuple layers (QLs) are covalently bonded within the layers but weakly held together by van der Waals forces between the adjacent QLs. It is also pointed out that Bi2Se3 is a topological insulator, making it a promising candidate for a wide range of electronic and optoelectronic applications. In this study, we investigate the growth of high-quality Bi2Se3 thin films on mica by the molecular beam epitaxy technique. The films exhibited a layered structure and highly c-axis-preferred growth orientation with an XRD rocking curve full-width at half-maximum (FWHM) of 0.088°, clearly demonstrating excellent crystallinity for the Bi2Se3 deposited on the mica substrate. The growth mechanism was studied by using an interface model associated with the coincidence site lattice unit (CSLU) developed for van der Waals epitaxies. This high (001) texture favors electron transport in the material. Hall measurements revealed a mobility of 726 cm2/(Vs) at room temperature and up to 1469 cm2/(Vs) at 12 K. The results illustrate excellent electron mobility arising from the superior crystallinity of the films with significant implications for applications in conducting electrodes in optoelectronic devices on flexible substrates.

Analysis Crystal Structure of La0.7Ba(1-xSrx)0.3MnO3 by Sol-Gel Method

Abstrak.Penelitian tentang struktur kristal bahan La0.7(Ba1-xSrx)MnO3 menggunakan metode sol-gel telah berhasil dilakukan. Bahan-bahan dasar yang digunakan dicampur di atas hot plate diaduk sambil ditetesi ammonia solution sehingga mencapai pH 7, selanjutnya didiamkan sampai diperoleh bentuk gel. Gel dikeringkan pada suhu 120°C, selanjutnya dilakukan pra-kalsinasi dengan suhu 650°C selama 6 jam, dilanjutkan dengan kalsinasi pada suhu 1000°C selama 12 jam, dan kemudian disinter pada temperatur 1200°C selama 12 jam. Hasil refinement data XRD memberikan informasi bahwa struktur kristal La0.7(Ba1-xSrx)MnO3 adalah rombohedral dengan space grup R-3c. Penambahan substitusi ion Sr2+ mengakibatkan terjadinya penurunan intensitas dan pergeseran puncak ke arah sudut yang lebih besar. Hal ini disebabkan karena pengaruh jari-jari ion Sr2+ yang lebih kecil dibandingkan dengan jari-jari ion Ba2+ . Abstract.In this research, La0.7(Ba1-xSrx)0.3MnO3 compound (x = 0; 0.2; 0.3; and 0.5) by sol-gel method has been investigated. The compound used is mixed on a hot plate until reached a pH 7 when dropped ammonia solution, then let stand until turn into a gel. Dehydrated gel at 120°C, pra-calcination at 650°C for 6 hours, calcination t 1000°C for 12 hours, and sintering at 1200°C for 12 hours. The result of refinement XRD pattern shown that samples are single phase with rhombohedral crystal structure with R-3c space group. The intensity decrease and peak list shift to larger angle when Sr-substitution increased, it’s caused ionic radii of Sr2+ is smaller than Ba2+ .

Microwave Absorbing Properties of Polycrystalline La0.67Sr0.33MnO3

Sample \ce {La_{0.67}Sr_{0.33}MnO3} has been successfully synthesized by sol gel method shown by the results of XRD formed a single phase with rhombohedral crystal structure. The results of SEM showed particles are agglomerated yet functional groups \ce {Mn-O-Mn} has been formed based on the results of FTIR. The ability of the sample to absorb the microwaves still lower that the value of reflection loss obtained at $-26.05$ dB.

Synthesis of Ternary Semiconductor Silver Bismuth Telluride by Chemical Bath Deposition

In this study, the synthesis of the ternary semiconductor sensitized silver bismuth telluride (AgBiTe2: SBT) particles was produced in the solution of AgNO3, Bi (NO3)3×5H2O and Na2O3Te by using a chemical bath deposition (CBD) method and annealing at 200°C for 1 h. According to scanning electron microscopy (SEM), the particle size of SBT after annealing was bigger than before annealing. Based on X-ray diffraction, the SBT after annealing for 1h became more crystalline. In addition, the XRF data also demonstrated that the SBT powder consists of Ag, Bi, and Te as dominant elements. The XRD result confirms a successful growth of the SBT particles with rhombohedral crystal structure. Based on the obtaining results, the SBT particles were successfully synthesized and potentially applied for solar cell application.

Investigation on structural, dielectric and ferroelectric properties of samarium-substituted BiFeO3–PbTiO3 composites

The polycrystalline samples of 0.8BiSmxFe[Formula: see text]O3–0.2PbTiO3 ([Formula: see text] and 0.20) were prepared by using the conventional solid-state reaction technique and sintered at high temperature (850[Formula: see text]C). X-ray diffraction (XRD) confirms the distorted rhombohedral crystal structure for all the composites at room temperature. The surface morphology was checked by field-emission scanning electron microscope (FESEM) technique and homogeneous mixing of the components was confirmed by energy-dispersive analysis of X-ray (EDAX). The detailed study of dielectric properties of the composites reveals an increasing nature of dielectric constant ([Formula: see text]) and loss tangent (tan[Formula: see text]) with the increase of temperature due to thermal activation. The Arrhenius plots of temperature dependence of AC conductivity yield the activation energy within the material at high-temperature range. The ferroelectric study shows that the remnant polarization decreases with the increase of Samarium (Sm) concentration.

Low-temperature precausticizing — a hopeful approach for green liquor desilication

We investigated silica removal by low-temperature precausticizing and the properties of second causticizing calcium carbonate (CCC). The results showed that about 89.3% of silica removal was achieved when 20% (the stoichiometric ratio) of causticizing quicklime was added for precausticizing at 20ºC for 60 min. After that, silica removal became slow. When no precausticizing quicklime was used to remove silica, the CCC particles had a rhombohedral crystal structure covered with amorphous material. As precausticizing quicklime was increased to 30%, the amorphous material and the crack disappeared, and the specific surface area decreased significantly. When CCC was used as filler, the Cobb value decreased significantly, and the sizing effect improved as precausticizing quicklime increased.