Ti Source Research Articles

Optimized and nonTi-site doped synthesis of lithium titanate by mechanochemical method

The Li2CO3-ammonia-ballmilling synthesis system of Li4Ti5O12 (LTO) was optimized and doped Li and O by theirs adjacent elements Mg and F respectively. By adjusting the ballmilling parameter, the distribution of Li and Ti sources, the hydrolysis rate and different nucleophilic / electrophilic hydrolysis path of Ti, and the interaction between Li and Ti species can be effectively controlled. The temperature programmed calcination is beneficial to the formation of the middle state (Li2TiO3), obtaining the high quality LTO. Mg and F doping can further optimize the hydrolysis and condensation degree of Ti source, the number of crystal nucleus and the particle size. Therefore, the initial first discharged capability of Mg doped LTO and F doped LTO reach to 152.4 mAh/g and 163.1 mAh/g at 5 C respectively, corresponding 32.4 % and 41.7 % enhancing compared to LTO (115.1 mAh/g). Moreover, the discharge voltage of LTO-Mg decreases from 1.5 V to 1.3 V.

Molten salt synthesis of Ti-Si-C coating on SiC particles and hot pressing of the prepared powders

SiC particles coated with Ti-Si-C layer were prepared by the molten salt synthesis method using NaCl-KCl eutectic mixture as the reaction medium and Ti metal powder as the Ti source. The synthesis was conducted under static argon atmosphere at 900 °C for 1–3 h. The post-synthesis treatment included dissolution of salts in hot water, followed by ultrasonic dispersion and sedimentation procedures. The thickness of the Ti-Si-C layer varied from 0.1 to 0.9 μm as the ratio of Ti to SiC components in the starting mixture changed from 0.05 to 0.4. The layer contained mainly nanocrystalline Ti5Si3, minor phases were TiC and Ti3SiC2. The as-prepared powders were hot pressed under 30 MPa at 1700 °C. The densification behavior of the samples during hot pressing as well as changes both in phase composition and in microstructure were studied. The flexural strength of the hot-pressed samples increased with an increase in the Ti:SiC molar ratio, giving the value as high as 213 ± 20 MPa for the sample with Ti/SiC = 0.4.

Optimization of zeolite ETS-10 synthesis for enhanced Pb(II) adsorption from aqueous solutions

The synthesis of zeolite ETS-10 is strongly influenced by factors such as pH, the amount of the structure-directing agent, hydrothermal temperature and duration, which collectively affect the material’s morphology and structure. This study thoroughly investigates the effects of these parameters on the synthesis of ETS-10 zeolite using TiCl3 and a waterglass solution. Characterization of the materials was performed through X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared spectroscopy (FT-IR), and nitrogen isotherm adsorption-desorption at 77 K (BET-BJH) techniques. The findings indicate that pH and the structure-directing agent significantly influenced the phase composition, while hydrothermal temperature predominantly determined the crystallization rate of ETS-10. Optimal synthesis conditions were established at an initial pH of 11, employing 0.3 g of the structure-directing agent and conducting hydrothermal crystallization at 230 °C for 24 h. Under these conditions, the ETS-10 zeolite produced exhibited a high surface area of 300.1 m2/g, making it effective in removing Pb2+ ions from solution. In particular, when tested under optimal conditions (pH 5) for 600 min, Pb (II) adsorption by ETS-10 reached a maximum uptake capacity of 956.19 mg/g, as determined by the Langmuir isotherm model. This capacity surpasses that of as-synthesized ETS-10 prepared from alternative Ti sources and other materials used in previous studies on Pb(II) adsorption.

Study on Photocatalytic Properties of TiO2 with Special Morphology by Using Natural Template

The TiO₂ photocatalysts with special morphology were synthesized in this paper. The authors used malus micro malus leaves and in docalamus leaves as template, and tetrabutyl titanate (TBT)as Ti source. The special shaped TiO₂ photocatalysts have high photocatalytic activity because of its unique morphology and s tructure. The structure and morphology of TiO₂ were characlerized by XRD and SEM, respectively. The photocatalytic activities were examined by the photodegradation of methylene blue (MB) under ultraviolet light (λ=365nm) iradiation. The results indicated that the TiO2 photocatalyst,using indocalamus leaves as templates, exhibited better adsorption and photocatalytic performance in degrading MB than using malus micro malus leaves, when the amount of nitric acid was 20 mL and following heat treatment at 600 ℃.

Sources and distribution of trace elements in surface snow from coastal Zhongshan Station to Dome A (East Antarctica)

The spatial distribution and possible sources of Al, As, Cd, Fe, Mn, Pb, Sb, Ti, V, and Zn were investigated in 120 samples of surface snow collected along a ∼1260 km long traverse from coastal Zhongshan Station to the Antarctic ice sheet summit (Dome A or Dome Argus, at 4093 m a.s.l.). The chemical composition of snow samples was analyzed using microwave-assisted acid treatment with HNO3/HF to determine element concentrations, reflecting their abundance in the Earth's crust. The observed relative concentration pattern of elements in snow suggests a predominant contribution from soil and rock dust particles. The spatial distribution of total element concentrations along the traverse revealed higher values in inland areas compared to coastal areas. The annual deposition flux of elements in each sampling site indicates a significant decreasing trend in Al, Ti, Zn, Fe, Cd, As, and Pb from the coast to inland areas. Significant variations in element concentrations and fluxes observed along the Antarctic traverse suggest a notable influence of distance from the coast on snow deposition patterns. Soil dust from coastal ice-free areas and human activities in scientific stations are the primary sources of analyzed elements in coastal snow, with marine biogenic emissions playing a marginal role, likely contributing to As and Cd. The contribution of sea salt spray to surface snow element concentrations in the East Antarctic traverse is negligible. An analysis of backward trajectories confirmed that long-distance transport from the South American continent and local Antarctic research stations potentially contributes to Antarctic snow elements.

Engineering metal oxide heterostructures derived from MOFs/MXene hybrids as efficient acetone sensor

Acetone, one of the most used solvents in industry and the laboratory, can anesthetize the central nervous system of humans and cause damage to the kidneys, pancreas, and liver. For the purpose of monitoring the leakage and concentration of acetone, α-/γ-Fe2O3/TiO2-X (α-/γ-Fe2O3-X) materials were successfully manufactured by in-situ solvothermal and calcination processes. Here, MIL-100-derived porous α-/γ-Fe2O3 and TiO2 nanoparticles are uniformly grown on the self-sacrificial template of exfoliated Ti3C2Tx nanosheets (ex-Ti3C2Tx) that simultaneously serve as the Ti source. The heterostructure between TiO2 and Fe2O3 therein is conducive to carrier transfer and sharp resistance change. And bulk resistance-controlled γ-Fe2O3 is able to raise the response to gas. Besides, the porous structure of α-/γ-Fe2O3-X could create plenty of oxygen vacancies and surface functional groups, which facilitate diffusion and contact interaction between acetone and active sites. Accordingly, the α-/γ-Fe2O3-X endow exceptional response (R = 105.5) towards 100 ppm acetone at 240 ℃, fast response/recovery time, outstanding selectivity and stability. To further substantiate this promotion mechanism, density functional theory (DFT) calculations were carried out for investigating the adsorption behavior of α-/γ-Fe2O3-X for acetone.

Intracavity frequency doubling acousto-optic Q-switched high repetition rate high-energy Nd:YLF laser.

The ongoing advancement of Ti:sapphire femtosecond laser technology has drawn increasing attention to high repetition rate, high-energy green lasers as ideal pump sources for Ti:sapphire regenerative amplifiers. This study employed a neodymium-doped yttrium lithium fluoride (Nd:YLF) as the gain medium, supplemented with side-pumped laser diodes, acousto-optic Q-switching, and intracavity frequency doubling technologies. The results demonstrated a repetition rate ranging from 1-10kHz, a pulse width of less than 100ns, and a single pulse energy exceeding 50mJ at 527nm green light output. Furthermore, an operating stability (RMS) of ≤0.15% was maintained for 14h at a repetition rate of 1kHz and an output power of 40W.

Limits on Ti Element Transfer in Submerged Arc Welding: Thermochemical Analysis

TiO2 inclusion formation in the weld pool is required to produce potent nucleation sites for acicular ferrite microstructure formation. Weld metal oxygen content must be limited to ensure acceptable materials properties, although sufficient oxygen is required for inclusion formation. Weld pool oxygen is sourced from the decomposition of flux oxides. Weld metal oxygen is controlled with flux chemistry formulation by CaF2 dilution of oxides. In conventional submerged arc welding (SAW), the flux is the source of weld metal Ti. Transfer of Ti from the slag appears to be limited to 400 parts per million (ppm). SAW modification by metal powder additions changes the element transfer reactions. Thermochemical analysis is applied to explain the limitations in Ti transfer from the slag, compared to improved reaction conditions for Ti element transfer in the aluminum‐assisted Ti alloying of weld metal. Low TiO2 activity due to low flux TiO2 content from CaF2 dilution and Ti loss from Ti‐fluoride gas formation limits Ti transfer from slag. Aluminum‐assisted alloying of the weld metal shifts the gas composition from Ti‐fluoride formation to Al‐fluoride formation and lowers the system partial oxygen pressure to increase the weld metal Ti content, with acceptable ppm O remaining in the weld metal.

Higher heavy metal contamination indoors than outdoors during COVID-19 in Mexico City

People spend most of their time indoors, especially during the coronavirus disease. Prolonged exposure to heavy metal-contaminated dust can be harmful to human health. The objectives of this study were to identify the contamination level in outdoor and indoor dust, compare contamination in both environments, and assess the human health risk. Two-hundred thirty-nine samples of dust were taken by Mexico City citizens in 38 homes on the weekends of May 2020. Heavy metal concentrations were measured through XRF. The contamination level was set using the contamination factor with a local and global background value, mixed linear models were used to identify indoor and outdoor differences, and USEPA human health risk methodology was used. Pb, Zn, and Cu had the highest contamination levels, followed by Sr and Mn, using both the local and global background values. The Pb, Zn, and Cu contamination was greater indoors, while higher Mn, Sr, and Fe were detected outdoors. According to the outdoor/indoor ratios, the main sources of Ca, Pb, Zn, and Cu must be indoors, while the main sources of Fe, Mn, Sr, Y, and Ti are outdoors. A human health risk was not detected, as the hazard index was lower than one. However, ailments can be developed due to exposure to Pb, Mn, and Fe in children (hazard index > 0.1). A higher risk due to Pb exposition was found indoors. Indoor environments in Mexico City were more contaminated by heavy metals and represented a higher risk to human health than outdoors during the pandemic isolation.

SIMPLE SEPARATION OF Ti(SO4)2 AND FeSO4 FROM H2SO4- FeSO4-Ti(SO4)2-H2O SYSTEM BASED ON SOLUBILITY PROPERTIES IN METHYL ALCOHOL

SIMPLE SEPARATION OF Ti(SO4)2 AND FeSO4 FROM H2SO4- FeSO4-Ti(SO4)2-H2O SYSTEM BASED ON SOLUBILITY PROPERTIES IN METHYL ALCOHOL

Development of manganese-iron mixed oxides reinforced with titanium and prepared from minerals for their use as oxygen carriers

Chemical Looping Combustion (CLC) allows CO2 capture at low cost. This technology is based on solid oxygen carriers which supply the oxygen required for combustion of the fuel while they experience successive reduction-oxidation cycles. Oxygen carriers based on minerals or industrial residues present the advantage of their low cost but complete combustion of the fuel is not always achieved. Manganese‑iron mixed oxides doped with titanium can improve combustion efficiency due to its oxygen uncoupling capability. Moreover, they present the advantage of their magnetic properties. The objective of this work was to produce this type of oxygen carriers from minerals/residues instead of from synthetic materials. Four oxygen carriers with a fixed Mn-Fe molar ratio were produced with a 7 wt.% TiO2 addition. Two manganese-based (MnSA and MnGBMPB) and one iron-based (Tierga) minerals were used as source of Mn and Fe, respectively. As source of Ti, the mineral ilmenite was used. After characterization of the materials, their reactivity was analysed in a TGA. The reactivity to the main combustion gasses was lower than that corresponding to similar oxygen carriers obtained from synthetic sources although they maintained their magnetic properties. Thus, its use as magnetic support of oxygen carriers was recommended. In this respect, first tests were conducted using CuO as active phase supported on one of the low-cost support materials produced in this work.

Peripherally tetra-substituted zinc (II) phthalocyanine sensitized TiO2 composite: Monitoring with tandem LC/MS and photocatalytic degradation of amoxicillin

In this study, zinc phthalocyanine (ZnPc)/TiO2 photocatalysts were obtained by sol-gel method using titanium isopropoxide and ZnPc as Ti source, and dye pigments, respectively. The synthesized (ZnPc)/TiO2 photocomposites were characterized by scanning electron microscopy/energy dispersive X-ray analyzer (SEM/EDX), X-ray diffraction (XRD) analysis, Fourier transform infrared spectroscopy (FTIR), and Ultraviolet–Visible Diffuse Reflectance Spectroscopy (UV-DRS). Photodegradation tests were evaluated in the ultraviolet and visible light range with photocatalysts to compare photocatalytic activity and investigate optimum mineralization of amoxicillin (AMX) by monitoring the triple quadrupole LC/MS-MS (Tandem MS2). Mineralization of AMX was also investigated by total organic carbon (TOC) analysis, suggesting that either amoxicillin itself or its resistant metabolites are still in solution and mineralization did not occur in an expected manner.

Atomic layer deposition of TiO2 nanolayer coated Vectran fabrics with enhanced UV-blocking performance and structural colors

Vectran fabrics are widely employed as the key material for the manufacturing of stratospheric airship. Nonetheless, Vectran faber would decompose due to the UV aging during the prolonged flying process. Herein, atomic layer deposition (ALD) technology was introduced to coat TiO2 nanolayers on the surface of Vectran fabrics. Titanium isopropoxide liquid was employed as the Ti source precursor throughout the deposition process. Compared with sol-gel vacuum infiltration technic, ALD modified Vectran yarns possessed higher surface uniformity, better UV blocking performance and lower density. Notably, thickness of the TiO2 nanocoating prepared through the ALD method was adjustable, which can optimize the UV resistance of Vectran yarn without significantly affect its density. Additionally, the nanolayer interface can induce structural coloration on the Vectran strand via diffraction phenomena. These outstanding merits endow ALD technic a promising choice to modify the surface of Vectran fiber used as the skin of stratospheric airships.

Fabrication of Ti3C2/TiO2/SrTiO3 ternary heterojunction photocatalyst with efficient charge separation for enhanced hydrogen evolution

In this work, a ternary Ti3C2/TiO2/SrTiO3 composite with heterogeneous network structure was prepared by two-step in situ hydrothermal synthesis method, which mainly involved the growth of TiO2 nanosheets and fibrous SrTiO3 sequentially on the Ti3C2 substrate using the Ti source inherent in Ti3C2 as the reaction site. The Ti3C2/TiO2/SrTiO3 heterojunction exhibited enhanced photocatalytic hydrogen evolution activity. When the doping amount of SrTiO3 was 5 wt%, the hydrogen evolution rate of 5MTS under full solar irradiation reached 14322.6 μmol·g−1·h−1, which was 10.6 times the rate of the Ti3C2/TiO2 composite without modified SrTiO3. Meanwhile, the 5MTS composites showed good stability in the photocatalytic hydrogen evolution cycle test. The enhanced activity and recyclability are mainly attributed to the strong light absorption ability, fast separation of photogenerated electron-hole pairs, and abundant catalytic active sites. In addition, the synthesis method utilizing an intrinsic Ti source also enhances the interfacial contact between Ti3C2, TiO2, and SrTiO3. This study provides an effective reference for the construction of perovskite-based or Ti3C2 co-catalyzed heterostructures and their application for the conversion of solar power to hydrogen energy.

Utilizing ferroelectric polarization differences in energy-storage thin film capacitors

Optimizing dielectric energy storage often involves increasing ferroelectric polarization and breakdown strength while delaying polarization saturation. Here, we investigated another factor named polarization difference ΔP to explore its effect on energy storage density of dielectric materials. The nominal compositions of [Bi0.75(Bi0.5Na0.5)0.25](Mg0.375Ti0.625x)O3 with excess Ti were selected to investigate dielectric energy characteristics. The excess Ti sources were found to effectively optimize the dielectric characteristics, with the highest Eb of 3382 kV/cm at x = 1.16 and the largest ΔP of 144 μC/cm2 at x = 1.24, respectively. Interestingly, the highest energy density of 141 J/cm3 (x = 1.24) was achieved at Eb = 2955 kV/cm rather than the maximum Eb, indicating a synergistic effect of polarization and dielectric breakdown. This means that tailoring ΔP can be another effective strategy for customizing the energy storage characteristics of electrostatic dielectric capacitors.

A New Study on Features Exploring of the Concept of Wen and Zhi in Lao-Zhuang’s Philosophy

For a long time, scholars have been applying the view of Confucius on Wen (文) and Zhi (質), centering on liyi (rites and rituals 禮儀) and renyi (benevolence and righteousness 仁義), to the Daoist concepts of them. This inevitably leads to many misunderstandings and overlooking the unique characteristics of the Daoist view. In the philosophy of Laozi and Zhuangzi, Zhi represents the natural state of human nature that is simple and desireless, while Wen refers to the corresponding expressions of speech and behavior generated based on Zhi. Under the Daoist Dao (the way 道)–Wu (object 物) model, the relationship between Wen and Zhi in Laozi and Zhuangzi is closely related to human nature and emotions, presenting Ti (source 體)–Yong (function 用) as the unity with nature as Ti and emotions as Yong. Secondly, Laozi and Zhuangzi’s view on Wen and Zhi is closely related to the thoughts of self-cultivation and governing the country, with the latter as the foundation for the former. Their view of Wen and Zhi shows the relationship of Ben (root 本)-Mo (branch 末). The probing into the Laozi and Zhuangzi’s concept of Wen and Zhi helps to understand the unique characteristics of the Daoist view, thereby further excavating the theoretical value and practical significance of the relationship between Wen and Zhi.

Enhanced electromagnetic wave absorption performance of multiphase (TiC/TiO2/C)/SiOC composites with unique microstructures

Incorporating multiphases can not only increase the attenuation capacity but also partially alleviate impedance mismatch. In this work, (TiC/TiO2/C)/SiOC composites were prepared from polymer-derived ceramics (PDCs) using a TiC nanoparticle modified polysiloxane (PSO) precursor at 900 °C under an Ar flow. The addition of TiC serves a dual purpose of enhancing conductivity loss and acting as a source of Ti for the generation of TiO2 particles. The combination of these particles with the carbon layer in amorphous SiOC creates a multiphase loss medium that significantly improves not only conductive loss and dipole polarization loss but also interface polarization loss, resulting in excellent impedance matching characteristics and EM wave absorption. Accordingly, the (TiC/TiO2/C)/SiOC with a TiC fraction of 20 wt% indicated a significant minimum reflection loss (RLmin) of −54.2 dB (over 99.999% absorption), and the effective absorption bandwidth (EAB) covered 4.2 GHz with a thickness ranging from 2.5 to 3.3 mm in the X band. A maximum radar cross section (RCS) reduction of 24.6 dBm2 was achieved at a scattering angle of 75°. Thus, the (TiC/TiO2/C)/SiOC composites have the potential to be utilized in radar stealth technology and reduce EM pollution, offering a novel approach to address these challenges.

2D TiO2/Ti3C2 conductive substrate enhanced the photoelectrochemical performance of hematite for water splitting

Since the photoelectrochemical properties of hematite are affected by its bulk and surface charge recombination, the introduction of a conductive substrate is a feasible way to improve its properties. In this paper, the Ti3C2 and TiO2/Ti3C2 conductive substrates were prepared by electrophoretic depositing multilayered Ti3C2 and TiO2/Ti3C2 nanosheet powders onto F-doped SnO2 glass (FTO), respectively. Then, the TiO2/Ti3C2-hematite and Ti3C2-hematite photoanodes were obtained by in-situ growth of hematite on Ti3C2 and TiO2/Ti3C2 conductive substrates by hydrothermal method. The photoanodes were characterized by scanning electron microscopy (SEM), UV–vis spectroscopy, X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS) and photoelectrical measurements. The photocurrent density of TiO2/Ti3C2-hematite reaches 1.29 mA cm−2 at 1.23 V (vs. RHE), which is 3.7 times than that of the FTO-hematite as 0.35 mA cm−2. The enhancement of the photocurrent response of TiO2/Ti3C2-hematite is mainly due to the great improvement of the bulk charge separation efficiency and the surface charge injection efficiency. This is attributed to the fact that the layered TiO2/Ti3C2 conductive substrate can improve the interface property of FTO/hematite, provide Ti source and a larger specific surface area for the growth of hematite.

A Recognition-Molecule-Free Photoelectrochemical Sensor Based on Ti3C2/TiO2 Heterostructure for Monitoring of Dopamine

Herein, a novel, recognition-molecule-free electrode based on Ti3C2/TiO2 composites was synthesized using Ti3C2 as the Ti source and TiO2 in situ formed by oxidation on the Ti3C2 surface for the selective detection of dopamine (DA). The TiO2 in situ formed by oxidation on the Ti3C2 surface not only increased the catalytically active surface for DA binding but also accelerated the carrier transfer due to the coupling between TiO2 and Ti3C2, resulting in a better photoelectric response than pure TiO2. Through a series of experimental conditions optimization, the photocurrent signals obtained by the MT100 electrode were proportional to the DA concentration from 0.125 to 400 µM, with a detection limit estimated at 0.045 µM. We also monitored DA in human blood serum samples using the MT100 electrode. The results showed good recovery, demonstrating the promising use of the sensor for the analysis of DA in real samples.

Reinforced copper matrix composites with highly dispersed nano size TiC in-situ generated from the Carbon Polymer Dots

In order to uniformly disperse the ceramic reinforcements synthesized in situ in the copper matrix composites, this study used Carbon Polymer Dot (CPD) as the carbon source and Cu-1.0%Ti alloy powder as the matrix to supply the Ti source for manufacturing in situ synthesized TiC/Cu composites. The results showed that TiC nano-precipitate formed in the grains interior and grain boundaries, with particle sizes that were similar to the CPD size and maintained a uniform distribution state. Compared with the matrix, 0.3 wt% CPD/Cu composite displayed the best strength-plastic compatibility, the UTS had achieved to be 385 MPa accompanied with a corresponding EL of 21%. This was owing to the dislocation hindrance caused by nano-carbide and excellent interface bonding between nano TiC and the Cu matrix. The density function theory calculation had supported our experimental results, which showed a tighter and stronger interface contact. This paper presents a new approach for studying in situ carbide precipitates. To create the in situ synthesized nano-sized TiC/Cu composites, Carbon Polymer Dot (CPD) was used as the carbon source. Theoretical and experimental findings support the strong interfacial bonding between TiC and copper matrix. The proposed method of in-situ synthesized nano-scaled TiC demonstrates to be a novel way to construct high-performance Cu matrix composites with both enhanced strength and plasticity.