Search

As a high energy density cathode material, further development of high working voltage spinel LiNi0.5Mn1.5O4 has hindered by its rapid capacity degradation. To address this, a hetero-valent substitution of magnesium for manganese was used to synthesize spinel LiNi0.5MgxMn1.5−xO4 (x = 0, 0.03, 0.05) via a microwave sol-gel method. XRD and refined results indicate that such strategy leads to the modification of the 16c interstitial sites. The electrical performance demonstrates that a modest substitution (x = 0.03) significantly improves both rate performance (113.1 mAh/g, charge and discharge at 5 C) and cycling stability (85% capacity retention after 500 cycles at 1 C). A higher substitution level (x = 0.05) markedly improves high-rate cycling performance, achieving 96% capacity retention after 500 cycles at 5 C. It offers tailored solutions for various application needs, including capacity-focused and high-current-rate applications. Furthermore, the stable LiNi0.5Mg0.05Mn1.45O4 sample could also serve as an effective coating layer for other electrode materials to enhance their cycling stability. [ABSTRACT FROM AUTHOR]

In this paper, we conducted a fundamental study concerning the effect of thermal treatment on the structure and morphology of 2 mol% vanadium doped ZnO nanopowders obtained by microwave assisted sol–gel method (MW). The samples were analyzed by DTA, FTIR, XRD, SEM, and UV–Vis spectroscopy. The DTA results showed that above 500 °C, there was no mass loss in the TG curves, and ZnO crystallization occurred. The XRD patterns of the thermally treated powders at 500 °C and 650 °C showed the crystallization of ZnO (zincite) belonging to the wurtzite-type structure. It was found that in the 650 °C thermally treated powder, aside from ZnO, traces of Zn3(VO4)2 existed. FTIR spectra of the annealed samples confirmed the formation of the ZnO crystalline phase and V–O bands. The micrographs revealed that the temperature influenced the morphology. The increase in the annealing temperature led to the grain growth. The SEM images of the MW powder thermally treated at 650 °C showed two types of grains: hexagonal grains and cylindrical nanorods. UV–Vis spectra showed that the absorption band also increased with the increasing temperature of thermal treatment. The MW sample annealed at 650 °C had the highest absorption in ultraviolet domain. [ABSTRACT FROM AUTHOR]

In this paper, we conducted a fundamental study concerning the effect of thermal treatment on the structure and morphology of 2 mol% vanadium doped ZnO nanopowders obtained by microwave assisted sol–gel method (MW). The samples were analyzed by DTA, FTIR, XRD, SEM, and UV–Vis spectroscopy. The DTA results showed that above 500 °C, there was no mass loss in the TG curves, and ZnO crystallization occurred. The XRD patterns of the thermally treated powders at 500 °C and 650 °C showed the crystallization of ZnO (zincite) belonging to the wurtzite-type structure. It was found that in the 650 °C thermally treated powder, aside from ZnO, traces of Zn3(VO4)2 existed. FTIR spectra of the annealed samples confirmed the formation of the ZnO crystalline phase and V–O bands. The micrographs revealed that the temperature influenced the morphology. The increase in the annealing temperature led to the grain growth. The SEM images of the MW powder thermally treated at 650 °C showed two types of grains: hexagonal grains and cylindrical nanorods. UV–Vis spectra showed that the absorption band also increased with the increasing temperature of thermal treatment. The MW sample annealed at 650 °C had the highest absorption in ultraviolet domain.

This study evaluated the influence of the TiO 2 nanoparticles (NPs) on the mechanical and chemical performance of Sn and Sn–Ag alloys. The XRD (X-ray diffraction) and HR-TEM (high resolution-transmission electron microscopy) methods were used to characterize the NPs synthesized by the sol-gel microwave process. The chemical composition of the alloys was Sn, Sn+3TiO 2 NPs, Sn–5Ag+1.5TiO 2 NPs, Sn–10Ag, and Sn–10Ag+3TiO 2 NPs, obtained from an experimental factorial design (EFD). A statistical model was used to determine the mechanical and chemical properties, showing the Vickers hardness response surface, tensile strength, wear, and corrosion resistance. The wear and corrosion tests for the various alloy compositions were performed using human artificial saliva solution. The results indicated that the Sn–10Ag+3TiO 2 NPs exhibited the highest mechanical performance due to their increased hardness (380 HV), tensile strength (370 N), and wear resistance (0.34 × 10−3 mm3 Nm−1); in all the cases, the inclusion of TiO 2 NPs enhanced the corrosion resistance of the alloys. According to the American Dental Association (ADA), Sn–10Ag+3TiO 2 NPs alloy could be classified as a possible type IV restorative material. [Display omitted] • The sol-gel microwave method was successfully used for the synthesis of TiO 2 NPs. • The addition of TiO 2 NPs modified the microstructure Sn–Ag alloys. • The addition of TiO 2 NPs enhanced hardness and wear performance of the Sn–Ag alloy. • The TiO 2 NPs remarkably increased the corrosion resistance of Sn–Ag alloy. • According to the results, Sn–Ag + NPs might be reclassified as ADA type IV material. [ABSTRACT FROM AUTHOR]

This study evaluated the influence of the TiO 2 nanoparticles (NPs) on the mechanical and chemical performance of Sn and Sn-Ag alloys. The XRD (X-ray diffraction) and HR-TEM (high resolution-transmission electron microscopy) methods were used to characterize the NPs synthesized by the sol-gel microwave process. The chemical composition of the alloys was Sn, Sn+3TiO 2 NPs, Sn-5Ag+1.5TiO 2 NPs, Sn-10Ag, and Sn-10Ag+3TiO 2 NPs, obtained from an experimental factorial design (EFD). A statistical model was used to determine the mechanical and chemical properties, showing the Vickers hardness response surface, tensile strength, wear, and corrosion resistance. The wear and corrosion tests for the various alloy compositions were performed using human artificial saliva solution. The results indicated that the Sn-10Ag+3TiO 2 NPs exhibited the highest mechanical performance due to their increased hardness (380 HV), tensile strength (370 N), and wear resistance (0.34 × 10 -3 mm 3 Nm -1 ); in all the cases, the inclusion of TiO 2 NPs enhanced the corrosion resistance of the alloys. According to the American Dental Association (ADA), Sn-10Ag+3TiO 2 NPs alloy could be classified as a possible type IV restorative material., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The Al-doped TiO 2 catalyst was synthesized by microwave-assisted sol-gel method. The physicochemical properties of the samples were determined by XRD, XPS, SEM, TEM, UV-Vis DRS, Raman spectroscopy, nitrogen physisorption, zetametry, and photoelectrochemical analysis. MP-AES determined the aluminum content in the catalysts. The evaluation of Al-doped TiO 2 photocatalytic activity for degradation of a plasticizer mixture (bisphenol A (BPA) and 4-tert butylphenol (4tBP)) was performed under UV and simulated solar light. The catalysts showed anatase crystalline phase, spherical morphology, and the crystallite size decreased as the Al content increased in TiO 2. The substitutional doping of Al3+ ions incorporated into the TiO 2 crystal lattice improved the photocatalytic performance of TiO 2 due to the enhanced surface acidity, and surface area, and reduced e - -h + recombination rate. A central composite design (CCD) with surface methodology was applied to identify the optimal degradation conditions evaluating the effect of Al doping within the content range 0.05–0.5 wt% on TiO 2 and solution pH in the photocatalytic reaction (3, 6, and 9). The Al-TiO 2 0.05% catalyst showed enhanced photocatalytic performance at pH 4.9, allowing 55% and 61% degradation percentages for 4tBP and BPA in 3 h under UV light irradiation. The photocatalytic oxidation mechanism of 4tBP and BPA with scavengers revealed that h + and •O 2 - were the major reactive species. The transformation products of 4tBP and BPA were identified by LC-MS technique. Coexistent substances in the WWTP showed no inhibitory effects against the photocatalytic decomposition of 4tBP and BPA, and the Al-TiO 2 catalyst demonstrated stability during the recycling experiments. [Display omitted] • Al is effectively incorporated in TiO 2 lattice by microwave assisted sol-gel method. • Al incorporation in TiO 2 enhances specific surface area and acidity and retards charge carrier recombination. • Al-TiO 2 shows enhanced activity on plasticizers degradation under UV and solar light. • BPA and 4 t BP degradation reaction pathways using Al-TiO 2 photocatalyst under UV irradiation are proposed. • Coexistent substances in WWTP do not affect plasticizers photocatalytic degradation. [ABSTRACT FROM AUTHOR]