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A homogenous and well-packed electron transport layer (ETL) is crucial in attaining high-performance perovskite solar cells (PSCs). Two vital tasks are carried out by ETL: excellent electron collection, and proficiently prevents the recombination of charge carriers. Hole transport layer (HTL) free screen-printed carbon-based perovskite solar cells (SP-C-PSCs) are particularly favored within the realm of PSCs due to their exceptional scalability, durability, and affordability. Titanium dioxide (TiO2) has been widely used as the ETL in these SP-C-PSCs due to its suitable band energy structure, ease of production, and low cost; nevertheless, it must be of high quality and uniformly deposited. Here experimental analytical study of PSCs was conducted, employed surface passivation to compact titania (c-TiO2) ETL using TiCl4 passivation agent through two different deposition techniques. This passivation is applied to lower its surface roughness, improve electron transport capability, increase crystallinity, reduce micro pores, exhibit better energy level alignment, and to reduce the recombination sites. Consequently, the device with surface passivation enhances the power conversion efficiency (PCE) and long-term ambient stability of PSCs by maximizing the c-TiO2 ETL electrical characteristics. It is also discovered that the passivated c-TiO2 layer has increased hydrophobicity and reduced the RMS surface roughness from 28.8 to 27.3 nm. The PCE of the fabricated SP-C-PSCs is improved by 32.34% through applying spin-coating TiCl4 passivation, and 21.74% enhancement is recorded by applying dip-coating TiCl4 passivation. Furthermore, after 1344 h of storage under ambient conditions without encapsulation, the device passivated with spin-coating retained 84.27%, the device passivated with dip-coating maintained 85.50%, while the reference device reserved just 75.84% PCE. [ABSTRACT FROM AUTHOR]

A homogenous and well-packed electron transport layer (ETL) is crucial in attaining high-performance perovskite solar cells (PSCs). Two vital tasks are carried out by ETL: excellent electron collection, and proficiently prevents the recombination of charge carriers. Hole transport layer (HTL) free screen-printed carbon-based perovskite solar cells (SP-C-PSCs) are particularly favored within the realm of PSCs due to their exceptional scalability, durability, and affordability. Titanium dioxide (TiO2) has been widely used as the ETL in these SP-C-PSCs due to its suitable band energy structure, ease of production, and low cost; nevertheless, it must be of high quality and uniformly deposited. Here experimental analytical study of PSCs was conducted, employed surface passivation to compact titania (c-TiO2) ETL using TiCl4 passivation agent through two different deposition techniques. This passivation is applied to lower its surface roughness, improve electron transport capability, increase crystallinity, reduce micro pores, exhibit better energy level alignment, and to reduce the recombination sites. Consequently, the device with surface passivation enhances the power conversion efficiency (PCE) and long-term ambient stability of PSCs by maximizing the c-TiO2 ETL electrical characteristics. It is also discovered that the passivated c-TiO2 layer has increased hydrophobicity and reduced the RMS surface roughness from 28.8 to 27.3 nm. The PCE of the fabricated SP-C-PSCs is improved by 32.34% through applying spin-coating TiCl4 passivation, and 21.74% enhancement is recorded by applying dip-coating TiCl4 passivation. Furthermore, after 1344 h of storage under ambient conditions without encapsulation, the device passivated with spin-coating retained 84.27%, the device passivated with dip-coating maintained 85.50%, while the reference device reserved just 75.84% PCE. [ABSTRACT FROM AUTHOR]

Copyright of Iron Steel Vanadium Titanium is the property of Iron Steel Vanadium Titanium Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the water/triethanolamine/ethanol system, TiCl4 aqueous solution is used as the precursor to regulate the conversion rate of TiCl4 by changing the reaction temperature, water volume, pH value, and ethanol amount. The experiment uses a single-factor method to investigate the dynamic relationship between Ti4+ concentration and time under various factors, thereby achieving controllable TiO2 production. The experimental results showed that under a single factor, the conversion rate showed a trend of first steep and then slow growth within 180 min. After 180 min, the conversion rate tended to stabilize. Considering various factors, it was found that VTiCl4:VC6H15NO3:VH2O:VC2H5OH = 1:6:15:30, pH = 7, reaction time at room temperature was 4 h, and the hydrolysis effect was good. The final conversion rate was 90.46%, and the hydrolysis reaction conforms to the first-order reaction equation. Kinetic parameters: pre-factor (A) = 0.107, activation energy (Ea) = 4488.65 J mol-1.

Titanium tetrachloride (TiCl4) is an important raw material for preparing metallic Ti and TiO2. At present, TiCl4 is mainly produced through boiling chlorination and molten salt chlorination. However, the quality of the titanium slag (or rutile) is significantly influenced by the preparation method. The content of Ca and Mg impurities in Panzhihua ilmenite is high, and the titanium slag after smelting is suitable for the production of TiCl4 via molten salt chlorination. However, chlorinated waste salt pollutes the environment, which should be avoided to meet sustainability goals. Herein, a novel process for preparing TiCl4 from Panzhihua ilmenite involving boiling chlorination is proposed. The carbothermal reduction of the ilmenite concentrate, acid leaching separation of the reduced products, and boiling chlorination process were investigated via X-ray diffraction, mineral dissociation analysis, scanning electron microscopy, and energy-dispersive spectroscopy. The reduced products, which are rich in titanium oxycarbide, Ti2O3 and iron, were prepared after reacting at 1550 °C for 3 h. The Fe content in the reduced products was reduced from 37.85 to 3.0 wt % after leaching with 1–5 wt. % hydrochloric acid. The obtained acid insoluble substances were chlorinated at 500 °C for 25 min to prepare TiCl4, resulting in a chlorination rate of 77.4%. The chlorination residue is rich in unchlorinated rutile, which can be recovered by repeating the boiling chlorination process. Therefore, the environmentally friendly boiling chlorination of Panzhihua ilmenite can be used to prepare TiCl4 avoiding the waste of chlorinated salt.

A cost‐effective strategy has been developed for the synthesis of polystyrene‐polyisobutylene‐polystyrene (PS‐PIB‐PS) triblock copolymer (SIBS) with relative narrow molecular weight distribution (MWD) via the addition of Ti(OiPr)4. First, the controlled polymerization of styrene (St) was achieved by using TMPCl/TiCl4/Ti(OiPr)4 initiating system from −80 to −50°C in a cost‐effective solvent mixture n‐Hexane/CH2Cl2 (v/v = 6/4). The –OiPr group was present in the form TiCl3(OiPr) for TiCl4/Ti(OiPr)4 ratio more than 3/1 and moderated the lifetime of the growing PS cation. Subsequently, Ti(OiPr)4 was added to the living charge of PIB initiated by initiator 1,4‐dicumyl chloride (DCC), followed by the addition of styrene monomer. The success of this developed synthesis methodology was confirmed by comparing the findings from GPC (Gel permeation chromatography) traces with and without the addition of Ti(OiPr)4. SIBS with nearly 30% weight content of PS (SIBS30) was successfully obtained with an optimally narrow MWD of 1.49 at −80°C by employing the TiCl4/Ti(OiPr)4 ratio of 6/1. Interestingly, SIBS30 with a very narrow PDI of 1.22 could be successfully synthetized at an elevated temperature of −60°C. [ABSTRACT FROM AUTHOR]

LiAlH 4 , known for its high hydrogen capacity and metastable nature, is a promising hydrogen source under mild conditions. However, its reversible regeneration from stable binary dehydrogenation phases (LiH/Al) is thermodynamically and kinetically hindered. By constructing a homogeneous and highly dispersed molecular layer of TiCl 4 on the surface of the Al reactant to enhance the kinetics of the multiphase interfacial reaction, we achieved the direct mechanochemical synthesis of nano-LiAlH 4 , bypassing the intermediate phase Li 3 AlH 6. Using the strong Lewis acidity of Ti4+, TiCl 4 was chemically adsorbed onto the surface of the Al powder through Ti-O-Al bonds, with a loading capacity of only 0.696 wt%. The obtained TiCl 4 surface-modified Al powder and LiH were hydrogenated by ball milling for 10 h under hydrogen pressure to synthesize nano-LiAlH 4 , which was then dehydrogenated at room temperature. This indicates that the crucial effects of the catalytic sites were dispersed on the reactant surface to ensure the local environment of the multiphase absorption/desorption hydrogen reaction interface and promote the reaction kinetics. [Display omitted] • Using the strong Lewis acidity of Ti4+, 0.696 wt% TiCl 4 was chemically adsorbed onto the surface of the Al powder through Ti-O-Al bonds. • Nano-LiAlH 4 was directly synthesized from the TiCl 4 catalyst surface-modified Al powder and LiH by hydrogen reactive ball milling, bypassing the intermediate Li 3 AlH 6. • The highly dispersed surface of the catalyst provided more active sites for the multiphase reaction, thereby accelerating the reaction kinetics at the interface between LiH, Al, and H 2. [ABSTRACT FROM AUTHOR]

In this study, the effect of deposition temperature of TiN thin films deposited using the thermal atomic layer deposition (ALD) method was investigated. TiCl4 precursor and NH3 reactive gas were used, and the deposition rate, resistivity change, and surface morphology characteristics were compared in the deposition temperature range of 400 °C–600 °C. While resistivity decreased to 177 µΩcm as the deposition temperature increased to 600 °C, an increase in surface roughness (Rq) to 0.69 nm and a deterioration in the step coverage were identified. In order to obtain a high-quality TiN thin film with excellent resistivity and step coverage characteristics even at low deposition temperatures, the TiN thin film was post-treated with plasma in a combination of N2/He gas ratio of 3:2 to confirm the change in resistivity. X-ray diffraction analysis confirmed crystallization change in the TiN thin film caused by plasma energy. As a result, the resistivity of the TiN thin film deposited at 400 °C was confirmed to be lowered by about 25%. [ABSTRACT FROM AUTHOR]

A new general approach for the synthesis of azolo[4,5‐b]quinolines via dealkylative TiCl4‐mediated cyclization of 2‐dialkylamino‐arylidene‐azol‐ones upon heating in dichloroethane is found. The reaction scope and limitations are established, showing that at least two different heterocyclic cores could be obtained. Dozen products were obtained in moderate to good yields (22–64 %). [ABSTRACT FROM AUTHOR]

[Display omitted] • The coagulation performance of two Sb species using TiCl 4 was compared in PDW. • TiCl 4 conducted better performance on Sb(Ⅲ) removal than Sb(Ⅴ) removal. • Chemical and electrostatic adsorption contributed more on Sb(Ⅲ) and Sb(Ⅴ) removal. • The adsorption energy of Sb(III) is stronger than Sb(V) in the coagulation system. Significant amounts of Sb(III) and Sb(V) are present in printing and dyeing wastewater (PDW), which leads to the detrimental effects on the environment if not treated properly. In this paper, the adsorptive removal of Sb(III) and Sb(V) by TiCl 4 derived flocs and the oxidation process were investigated. The results showed that TiCl 4 conducted superior coagulation performance on Sb(III) removal than Sb(V) in terms of dosage, pH range and immunity to interference. When the dosage was 50 mg/L and the final pH was 5.0, the concentration of Sb(III) and Sb(V) was reduced from 2000 μg/L to 100 μg/L and 180 μg/L, respectively. According to the Langmuir model, The adsorption for Sb(III) (74.27 mg/g) by TiCl 4 derived flocs was higher than Sb(V) (68.45 mg/g). The Sb(III) in the solution could partially inhibit the adsorption of Sb(V). It was also observed that the Sb(III) was oxidized to Sb(V), which was owing to the molecular oxygen during the coagulation and the flocs might act as catalyst. The actual printing and dyeing wastewater treatment experiments results showed that pre-reduction of Sb(V) to Sb(Ⅲ) could considerably improve the total Sb removal from 83 % to 98.8 %. The characterization results, such as zeta potential and x-ray photoelectron spectroscopy (XPS), indicated that the Sb(Ⅲ) removal was mainly achieved by chemisorption. The Sb(V) removal was mainly dependent on chemisorption and electrostatic adsorption, while the latter contributed more than former. The results of DFT calculations explained the reason for higher removal efficiencies of Sb(III) than Sb(V) in the TiCl 4 coagulation system. This study provides a new idea for the efficient removal of Sb(III) and Sb(V) using TiCl 4 in PDW to save the cost in engineering practice. [ABSTRACT FROM AUTHOR]

In the current study, Ziegler-Natta (Z-N) catalyst was synthesized via recrystallization method using MgCl2 as a support, AlCl3 as an activator and TiCl4 as a transition metal source. The TiCl4 used in the study was derived from Malaysian ilmenite through a sequential pyrometallurgical and hydrometallurgical process of ilmenite concentrate conversion to TiCl4. The recrystallization method of synthesis of the heterogeneous Z-N catalyst was studied by varying the synthesis parameters, such as the combined amount of MgCl2 and AlCl3, temperature, and amount of TiCl4, using statistical design of experiments. The investigation aimed at determining the best conditions for synthesizing the heterogeneous Z-N catalyst. The synthesis conditions posed a significant influence on the Ti content present in the catalyst product. The morphological and elemental analysis of SEM-EDX showed good spherical nature of the prepared catalysts. The XRD phase analysis detected the peaks of MgCl2, MgCl2-Ethanol, MgCl2/TiClx, and TiO2. The IR spectra confirmed the presence of the Mg-Cl bond at 1635 cm−1 and Ti-Cl bonds at 602 cm-1 and 498 cm-1. The produced catalyst contained a small amount of TiO2, which could be due to the seepage of moisture during the analysis or storage of the sample. The most favourable combination of the studied parameters was determined based on the Ti content in the catalyst product. Therefore, the best conditions for synthesizing the heterogeneous Z-N catalyst with high Ti content (181.1 mg/L) was at a combined amount of 2 g of MgCl2 for 6 g of AlCl3, crystallization temperature of 80 °C, and 2 mL dosage of TiCl4. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

The hydrolysis of Ti(IV)-bearing acid solution to prepare titanic acid particles is a crucial step for the production of TiO 2 material. The hydrolysis which takes place in HCl medium was investigated particularly with the purpose of preparing coarse particles with narrow size distributions for applications such as Ti metal powder production. The key factors that affect the hydrolysis ratio and rate, the morphology, and the size of the titanic acid particles were investigated. The results illustrated that temperature, initial free acid and equivalent TiO 2 concentrations cross-influence the above-mentioned key attributes of the product particles. Near spherical rutile particles with a D50 of around 30 μm were obtained under the optimal parameters. Four stages, including incubation, acceleration, near steady-state reaction, and deceleration, were observed during the progress of the hydrolysis reaction, while the precipitate morphology evolved from irregular to smooth, and to round as a result of the nucleus agglomeration. [Display omitted] • Micron-sized and near spherical TiO 2 powder is prepared via hydrolysis. • Initial free acid and equivalent TiO 2 concentrations cross-influence the size and morphology. • A sigmoid shape of yield vs. time illustrates the progression of hydrolysis with four stages. [ABSTRACT FROM AUTHOR]

This data article provides a dataset of the energetically accessible structures including the most stable structures of xMgCl2/yTiCl4 nanoplates (x = 6–19, y = 0–4). TiCl4-capped MgCl2 nanoplates are regarded as the building block of the Ziegler–Natta catalyst. The most stable structures were determined for MgCl2/TiCl4 nanoplates of different sizes and chemical compositions using a combination of the genetic algorithm and the DFT geometry optimization. The evolution in the genetic algorithm produced a number of meta-stable structures. A set of isomeric structures having similar energy to the most stable structure (termed energetically accessible structures) are provided as realistic models of MgCl2/TiCl4 nanoplates. These structures are useful for further investigation on the structural distribution of Ti species on MgCl2 regarding the Ziegler-Natta catalyst.

This paper describes the structural and photocatalytic studies of TiO 2 nanoparticles prepared by two different precipitation methods using titanium tetrachloride (TiCl 4) and titanium oxalate [Ti(C 2 O 4) 2 as raw materials for the first time. The samples were characterized by TG-DSC, XRD, TEM, EDS, SAED, UV–Vis, Raman, N 2 adsorption-desorption isotherms, and XPS to investigate the effects of salt type and calcination temperature on the crystal structure, morphology, composition, energy band gap and photocatalytic activity of TiO 2 nanoparticles. Results indicated that when TiCl 4 was used as Ti source, the crystallization temperature of amorphous TiO 2 to anatase TiO 2 was as low as 250 °C, but it increased to ~450 °C when Ti(C 2 O 4) 2 was selected. Besides, TiCl 4 was able to dynamically modify the crystalline structure of TiO 2 nanoparticles from anatase into rutile after calcination at ~450 °C, however this temperature was increased to ~850 °C for Ti(C 2 O 4) 2. The optimal photocatalytic property of methyl orange (MO) degradation in two TiO 2 systems was 99.08% and 38.6% with corresponding calcination temperatures of 450 °C and 550 °C, respectively, which was mainly correlated with the different crystal structure and crystallite size. [ABSTRACT FROM AUTHOR]

The application of CO 2 power cycles has proved to be particularly advantageous to exploit high-temperature heat sources (500–800 °C) in the case of available low-temperature heat sinks (15–25 °C). Otherwise, the efficiency of these cycles is strongly reduced when cold sink temperatures are higher than 25 °C. This is the case, for example, of solar applications installed in desert areas whose cold sink is represented by available hot air. Due to these high temperatures of the cold sink, CO 2 is inevitably compressed in the supercritical phase thus preventing its more efficient pressurization in the liquid phase. One of the solutions envisaged to overcome this problem consists of adding to CO 2 a small amount of one or more chemicals, resulting in a mixture with a critical temperature higher than the one of pure CO 2 (about 31 °C). This preserves the working fluid compression in its liquid phase, even in the case of cold sinks with temperatures greater than 25 °C. This research aims to show that the addition to CO 2 of a specifically selected second component enables to increase the critical temperature up to 45 °C with relevant improvements of cycle efficiency with respect to pure-CO 2 power cycles. In particular, after summarizing the most relevant criteria to be accounted for when selecting CO 2 -additives, the paper warns about the thermodynamic effects deriving from adding to CO 2 a second component characterized by a much more high critical temperature, such as the occurrence of infinite-pressure critical points and multiple-phase liquid-liquid and vapor-liquid critical points. Moreover, the paper specifically analyses the thermodynamic properties of CO 2 -TiCl 4 mixtures which, depending on the content of TiCl 4 , may lead to a mixture characterized by the sought higher critical temperature. While studying this mixture, it has been observed that it presents multiple-phase critical points. For the sake of completeness, the paper also shows how do enthalpy and specific volume change in response to pressure variations in the event of either liquid-liquid or vapor-liquid critical points. This research finally shows the comparison between performances of power cycles which use, as working fluid, either pure CO 2 or the specifically designed CO 2 -TiCl 4 mixture. As expected, the TiCl 4 addition brings about a significant efficiency gain. • A CO 2 -based mixture suitable for power plant production is defined. • The thermodynamic properties for the CO 2 -TiCl 4 mixture are evaluated. • Thermodynamic cycles operating with the CO 2 -TiCl 4 mixture are defined and their performances are estimated. • Comparison between recuperative cycle and recompressed cycle are proposed. • Solar application with both the molten salt technology and the liquid metal technology are assessed. [ABSTRACT FROM AUTHOR]

The engineering of the electron transport layer (ETL)/light absorber interface is explored in perovskite solar cells. Single‐crystalline TiO2 nanorod (NR) arrays are used as ETL and methylammonium lead iodide (MAPI) as light absorber. A dual ETL surface modification is investigated, namely by a TiCl4 treatment combined with a subsequent PC61BM monolayer deposition, and the effects on the device photovoltaic performance were evaluated with respect to single modifications. Under optimized conditions, for the combined treatment synergistic effects are observed that lead to remarkable enhancements in cell efficiency, from 14.2% to 19.5%, and to suppression of hysteresis. The devices show JSC, VOC, and fill factor as high as 23.2 mA cm−2, 1.1 V, and 77%, respectively. These results are ascribed to a more efficient charge transfer across the ETL/perovskite interface, which originates from the passivation of defects and trap states at the ETL surface. To the best of our knowledge, this is the highest cell performance ever reported for TiO2 NR‐based solar cells fabricated with conventional MAPI light absorber. Perspective wise, this ETL surface functionalization approach combined with more recently developed and better performing light absorbers, such as mixed cation/anion hybrid perovskite materials, is expected to provide further performance enhancements. [ABSTRACT FROM AUTHOR]

An efficient method for the synthesis of 2,5-disubstituted 1,3,4-oxadiazoles and 1,3,4-thiadiazoles has been developed. Various hydrazides or thionyl hydrazides readily react with DMA derivatives in the presence of TiCl4 as a catalyst to afford the desired products. This protocol provides a simple and economical procedure that affords the target products with good yields and wide substrate scope. [ABSTRACT FROM AUTHOR]

Artichoke peels were used to produce activated carbon using chemical activation methods. Two activation protocols were compared: a two-step method A and a one-step method B. As newly used activating agents, KCl, CrCl3 and TiCl4 were compared. The results show that method B is superior to A. KOH with method B had an area of 2321 m2/g and a total pore volume 1.0071 cm3/g, of which 0.9794 cm3/g was confined to micropores. The corresponding values for KCl are 1731, 0.6925 and 0.6718. TiCl4 had lower but comparable values with those of KCl. CrCl3 appeared to be the least successful among the three newly used activating agents. The post-activation washing step strongly affects the characteristics of the final product. The differences among the effects of Zn, Cr and Ti are discussed in terms of the differences in polarizing power.

The effect of the number and arrangement of TiO2‐based photoanode layers on the efficiency of dye‐sensitized solar cells (DSSCs) was investigated. Compact, mesoporous, and blocking layers of TiO2 were prepared to form monolayer, bilayer, and trilayer photoanodes. Compact and blocking TiO2 layers were prepared using dip‐coating technique, whereas the doctor‐blade method was employed to prepare TiO2 paste layers using nanoparticles prepared by the sol–gel method. The crystalline structure of photoanodes was characterized by X‐ray diffraction (XRD) measurements and their morphology and thickness were characterized by the scanning electron microscopy (SEM) technique. The photovoltaic performance of constructed DSSC devices was investigated and the optimum arrangement was identified and explained in terms of dye loading enhancement and recombination reduction at the fluorine‐doped tin oxide (FTO)/electrolyte interface. [ABSTRACT FROM AUTHOR]

It is well known that electron transport layer (ETL) plays an indispensable role in the planar heterojunction perovskite solar cells (PSCs). TiO2 is widely used as an ETL material due to its excellent transport properties, however, the presence of defects in the TiO2 layer diminishes the power conversion efficiency (PCE) of the devices. Herein, we introduce a method of low-temperature TiCl4 treatment to deposit a TiOx layer on the surface of TiO2 film, which can effectively passivate trap states at the TiO2 surface. Moreover, the treating process is optimized to be 30min using a 40mM TiCl4 aqueous solution. Benefiting from this, we obtain the champion device with the highest PCE of 18.47%, which is mainly due to the reduction of surface defects and the deposition of the well-crystallized perovskite films. Besides, the modified PSCs exhibit an average PCE of 17.59%, which is much better than the control devices.

Here the aromatic formylation mediated by TiCl4 and dichloromethyl methyl ether previously described by our group has been explored for a wide range of aromatic rings, including phenols, methoxy- and methylbenzenes, as an excellent way to produce aromatic aldehydes. Here we determine that the regioselectivity of this process is highly promoted by the coordination between the atoms present in the aromatic moiety and those in the metal core.

Graphical abstract Highlights • Reporting a synthesis of syn -vicinal diamines. • Highly stereoselective allylation was accomplished by TiCl 4. • Reporting a synthesis of an intermediate of an oseltamivir derivative. • A new chiral synthon syn -vicinal diamine compound was used for the syntheses. Abstract The stereoselective allylation of acyclic chiral α-amino aldimines affording vicinal diamines, mediated by various Lewis acids (TiCl 4 , SnCl 4 , MgBr 2 ·OEt 2 , BF 3 ·OEt 2 , ZnCl 2), is described. The TiCl 4 -mediated allylation of an α- N -Boc aldimine afforded the allylation product with syn -selectivity, which in turn was used for the synthesis of an intermediate of an oseltamivir derivative. [ABSTRACT FROM AUTHOR]

In this paper, titanium dioxide (TiO2) nano-particles were synthesized by the sol-gel method by using Titanium tetrachloride (TiCl4) solution as precursor. The effects of calcination temperature were determined. The samples were examined using X-ray diffraction (XRD), scanning electron microscope (SEM) and Fourier-transform infrared spectroscopy (FT-IR) analysis. X-ray diffraction measurements showed that TiO2 nano-particles were polycrystalline with rutiles and anatase phases. The Surface morphological studies obtained from SEM micrographs. Particle size increased from 43 to 500 nm when calcination temperature was 500 °C. In the FT-IR spectra, the peaks observed below 700 cm-1 due to stretching and bending vibrations of Ti-O-Ti bond. [ABSTRACT FROM AUTHOR]

In this piece of research, we have synthesized titanium dioxide (TiO2) powders from titanium tetrachloride (TiCl4) as an inorganic precursor by applying the sol-gel method. The effect of the calcination temperature in the range 400-800 °C on the photocatalytic performance of TiCl4 nanoparticles was studied. The samples were characterized by TEM, BET surface area measurement, DRS and XRD. They were then used for the photodegradation of two model pollutants - phenol and formic acid - under exposure to UV-A radiation. Despite the fact that the adsorption of both phenol and formic acid on the various TiO2 nanomaterials followed the Langmuir model, their degradation kinetics followed the Langmuir-Hinshelwood model. The results emphasized a strong increase in the adsorption and in the photocatalytic activity with the TiO2 calcined at 600 °C which was nearly 1.5 times higher than that of TiO2-P25 in the case of formic acid. For the degradation of phenol, TiO2-600 had a similar activity as TiO2 P25. This is related to their tendency to degrade the intermediate products than the phenol itself. A formal mechanism scheme of phenol degradation has been proposed. The maximum photocatalytic efficiency was reached with the sample calcined at a temperature of 600 °C, while a further increase in temperature depleted the photocatalytic response. The highest photocatalytic activity of the sample calcined at 600 °C can be attributed to the improvement of the crystallization and the optimal anatase/rutile ratio (96/4). [ABSTRACT FROM AUTHOR]

Artichoke peels were used to produce activated carbon using chemical activation methods. Two activation protocols were compared: a two-step method A and a one-step method B. As newly used activating agents, KCl, CrCl 3 and TiCl 4 were compared. The results show that method B is superior to A. KOH with method B had an area of 2321 m 2 /g and a total pore volume 1.0071 cm 3 /g, of which 0.9794 cm 3 /g was confined to micropores. The corresponding values for KCl are 1731, 0.6925 and 0.6718. TiCl 4 had lower but comparable values with those of KCl. CrCl 3 appeared to be the least successful among the three newly used activating agents. The post-activation washing step strongly affects the characteristics of the final product. The differences among the effects of Zn, Cr and Ti are discussed in terms of the differences in polarizing power. [ABSTRACT FROM AUTHOR]

In this work the kinetics of the TiCl4⇌TiCl3+Cl reaction is studied theoretically. A variable-reaction coordinate transition-state theory (VRC-TST) is used to calculate the high-pressure limit rate coefficients. The interaction energy surface for the VRC-TST step is sampled directly at the CASPT2(6e,4o)/cc-pVDZ level of theory including an approximate treatment of the spin-orbit coupling. The pressure-dependence of the reaction in an argon bath gas is explored using the master equation in conjunction with the optimised VRC-TST transition-state number of states. The collisional energy transfer parameters for the TiCl4-Ar system are estimated via a "one-dimensional minimisation" method and classical trajectories. The Ti-Cl bond dissociation energy is computed using a complete basis set extrapolation technique with cc-pVQZ and cc-pV5Z basis sets. Good quantitative agreement between the estimated rate constants and available literature data is observed. However, the fall-off behaviour of the model results is not seen in the current experimental data. Sensitivity analysis shows that the fall-off effect is insensitive to the choice of model parameters and methods. More experimental work and development of higher-level theoretical methods are needed to further investigate this discrepancy. [ABSTRACT FROM AUTHOR]

Copyright of Journal of the Tianjin Polytechnic University / Tianjin Gongye Daxue Xuebao is the property of Journal of Tianjin Polytechnic University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Amorphous thin-film TiO x prepared via atomic layer deposition (ALD) has been identified as one of the most promising materials for use in transparent passivating contacts in high-efficiency and low-cost crystalline silicon (c-Si) solar cells. As highlighted in this work, the passivation performance of ALD TiO x layers strongly depends on the metal precursor used, with films prepared using TiCl 4 recently showing the best results. However, a full understanding of how such films achieve their high level of surface passivation has not yet been demonstrated. This study provides a clear demonstration that a key part of this passivation mechanism is due to chlorine (Cl) accumulation at the Si surface. This mechanism is demonstrated to be quite general in nature by showing how 2 nm of ALD TiO x (TiCl 4 + H 2 O) can be applied as a capping layer for either ZnO or Al 2 O 3 interlayers to dramatically reduce silicon surface recombination. Cl depth profiles obtained using secondary ion mass spectrometry confirm the presence of Cl extending through the depth of the interlayers with a peak at the silicon interface. Remarkably, this diffusion of Cl is observed following low-temperature (75 °C) deposition of the TiO x capping layer, without any subsequent thermal treatment. Contrary to earlier studies that treated residual Cl in ALD films as a general contamination issue, these findings reveal unequivocally that chlorine plays a crucial role in Si surface passivation and can be classed as an effective passivation element, similar to hydrogen in its ability to passivate Si dangling bonds. The outcomes of this research emphasize the importance of residual chlorine in enhancing the passivation of buried interfaces and provide additional motivation for employing metal chloride precursors for silicon surface passivation applications.

Titanium complexes have been widely used as catalysts for C‑C bond-forming processes via free-radical routes. Herein we provide an overview of some of the most significant contributions in the field, that covers the last decade, emphasizing the key role played by titanium salts in the promotion of selective reactions aimed at the synthesis of multifunctional organic compounds, including nucleophilic radical additions to imines, pinacol and coupling reactions, ring opening of epoxides and living polymerization.

3-Substituted 2-(phenylthio)acrylates prepared from aldol condensation using titanium tetrachloride were employed to synthesize benzo[b]thiophenes. The acrylates containing aryls and alkyls generated the desired benzo[b]thiophenes in reasonable yields under the optimized Heck condition, but acrylates having heteroaryls gave the desired products in poor yields or no products under the condition. [ABSTRACT FROM AUTHOR]

Titanium nitride (TiN) not only was utilized in the wear-resistant coatings industry but it was also adopted in barrier processes for semiconductor manufacturing. Barrier processes include the titanium (Ti) and TiN processes, which are commonly used as diffusion barriers in via/contact applications. However, engineers frequently struggle at the via/contact module in the beginning of every technology node. As devices shrink, barrier processes become more challenging to overcome the both the physical fill-in and electrical performance requirements of advanced small via/contact plugs. The aim of this paper is to investigate various chemical vapor deposition (CVD) TiCl4-based barrier processes to serve the application of advanced small via/contact plugs and the metal gate processes. The results demonstrate that the plasma-enhanced chemical vapor deposition (PECVD) TiCl4-based Ti process needs to select a feasible process temperature to avoid Si surface corrosion by high-temperature chloride flow. Conventional high step coverage (HSC) CVD TiCl4-based TiN processes give much better impurity performance than metal organic chemical vapor deposition (MOCVD) TiN. However, the higher chloride content in HSC film may degrade the long-term reliability of the device. Furthermore, it is evidenced that a sequential flow deposition (SFD) CVD TiCl4-based process with multiple cycles can give much less chloride content, resulting in faster erase speeds and lower erase levels than that of conventional HSC TiN. [ABSTRACT FROM AUTHOR]

The synthesis of (2S)-2-benzyloxymethyl-3-(2-fluoro-4-methoxyphenyl)- propionic acid, (2S)-2-benzyloxymethyl-3-(2-fluoro-4-methylphenyl)propionic acid and (2S)-2-benzyl-oxymethyl-3-(2,4-dimethylphenyl)propionic acid has been achieved by TiCl4 mediated alkylation of the corresponding (4R)-4-benzyl-3-[3-(2-fluoro-4-methoxyphenyl-, 2-fluoro-4-methylphenyl-, 2,4- dimethylphenyl-)propionyl]-2-oxazolidinones, followed by hydrolysis of the chiral auxiliary. The stereochemistry of the alkylation reaction was confirmed by an X-ray crystal structure of (4R)-4-benzyl-3-[(2S)-2-benzyloxymethyl-3-(2- fluoro-4-methylphenyl)propionyl]-2-oxazolidinone.

• Employment of the MEDT affords more information than FMO. • The TiCl 4 and TiF 4 catalysts modify the electrophilic parr functions of acrylic acid. • The TiCl 4 catalysts increase the yield and para selectivity of this reaction. The [4 + 2] cycloaddition reaction catalyzed by the Lewis acids TiC l 4 & Ti F 4 of acrylic acid and isoprene has been studied within the molecular electron density theory (MEDT) and frontier molecular orbital theory (FMO) at the SDD computing level. FMO theory indicates that the presence of TiC l 4 and TiC l 4 approvals the interactions between the molecular orbitals of the reactants, hence increasing the reaction yield. But utilization of the MEDT gives more information than FMO. From MEDT, we remarked that the existence of the Ti F 4 and TiC l 4 as catalysts modifies the electrophilic Parr functions of acrylic acid 2, the carbon atom C'3 has 0.39 and 0.16 respectively, whereas the center C'2 becomes negative, which augments the regioselectivity. The presence of the TiF 4 catalyst increases the reaction yield and increases the regioselectivity of the para product, when we change the Ti F 4 by TiC l 4 reduces the para activation energy and augments the exothermic character of the meta product by 0.28 kcal/mol and the para product by 1.87 kcal/mol, designating that para product becomes thermodynamically more favourable than the meta product, the energy differentiation between the para and meta activation energy catalyzed by TiC l 4 becomes 2.50 kcal/mol, which explicates the increase in yield and para selectivity of this reaction. Moreover, the ELF study indicates that this catalyzed and non-catalyzed reaction has an asynchronous mechanism. [ABSTRACT FROM AUTHOR]

[Display omitted] • First time-resolved transient transmission spectroscopic study of SnCl 4 and TiCl 4. • High resolution isotopically split FFT spectra of symmetric ν 1 vibration. • Established influence of intermolecular interactions on ν 1 band shape. • Theoretical model allowing to determine intermolecular force constants. • Time evolution of vibrational spectra via Windowed FFT. Herewith, for the first time, we present the vibrational spectra collected for liquid TiCl 4 and liquid SnCl 4 by use of time resolved transient transmission spectroscopy. Of our interest is the isotopically split isotropic ν 1 intramolecular vibrational band, the shape of which is very sensitive to intermolecular interactions. The high resolution spectra, obtained as fast Fourier transforms of the time domain signals acquired in transient transmission experiment, are compared with spontaneous Raman spectra. The dependence of the spectrum shape on intermolecular interactions has been established by diluting TiCl 4 and SnCl 4 in CS 2 at different concentrations. Fitting the simplified oscillatory model of a liquid to FFTs of time domain signals in transient transmission experiment we have found intermolecular force constants and decoherence lifetimes for all concentrations. Application of the pump–probe spectroscopic technique and windowed fast Fourier transform procedure allowed us to observe the evolution of the spectral shape, and thus of the intermolecular forces, after the liquid has been perturbed by the femtosecond pump pulse. [ABSTRACT FROM AUTHOR]

Here the aromatic formylation mediated by TiCl4 and dichloromethyl methyl ether previously described by our group has been explored for a wide range of aromatic rings, including phenols, methoxy- and methylbenzenes, as an excellent way to produce aromatic aldehydes. Here we determine that the regioselectivity of this process is highly promoted by the coordination between the atoms present in the aromatic moiety and those in the metal core. [ABSTRACT FROM AUTHOR]

A TiCl4-mediated reaction for the direct amination of α-hydroxy amides has been developed. This simple, general, additive/base/ligand-free reaction is mediated by economical TiCl4. The reaction runs under mild conditions. This highly efficient C−N bond formation protocol is valid for diverse amines, including primary, secondary and heterocyclic amines, and even a primary amide and indole. [ABSTRACT FROM AUTHOR]

The recovery of titanium from the slurry formed in crude titanium tetrachloride and recycling of NaCl-AlCl3 was studied. Experimental results showed that the titanium contained in the slurry can be effectively recovered by reactive distillation with molten NaCl-AlCl3. More than 99% of titanium was volatilized from the slurry by distilling at 453 K for 40 min with slurry to molten salt (S/M) ratio of 1.8:1. Experiments found that the recovered titanium includes the chloride and oxychloride as the TiOCl2 containing in the slurry was changed into TiCl4 by the complex reactions of TiOCl2 with AlCl3 and NaAlCl4 during reactive distillation. The behavior of molten NaCl-AlCl3 during vacuum distillation was studied and NaCl-AlCl3 was recovered from the reactive distillation residue (RD residue) by vacuum distillation. The study showed that high temperature and vacuum were favorable to the evaporation of NaCl-AlCl3. Meanwhile, 97.8% of AlCl3 and 66.8% of NaCl were recovered from RD residue as distillate. The distillate was a mixture of AlCl3 and NaAlCl4, which can be returned to reactive distillation by adding a small amount of NaCl. [ABSTRACT FROM AUTHOR]

The replacement of oxide semiconducting TiO2 nano particles with one dimensional TiO2 nanotubes (TNTs) has been used for improving the electron transport in the dye-sensitized solar cells (DSSCs). Although use of one dimensional structure provides the enhanced photoelectrical performance, it tends to reduce the adsorption of dye on the TiO2 surface due to decrease of surface area. To overcome this problem, we investigate the effects of TiCl4 treatment on DSSCs which were constructed with composite films made of TiO2 nanoparticles and TNTs. To find optimum condition of TNTs concentration in TiO2 composites film, series of DSSCs with different TNTs concentration were made. In this optimum condition (DSSCs with 10 wt% of TNT), the effects of post treatment are compared for different TiCl4 concentrations. The results show that the DSSCs using a TiCl4 (90 mM) post treatment shows a maximum conversion efficiency of 7.83% due to effective electron transport and enhanced adsorption of dye on TiO2 surface. [ABSTRACT FROM AUTHOR]

The replacement of oxide semiconducting TiO2 nano particles with one dimensional TiO2 nanotubes (TNTs) has been used for improving the electron transport in the dye-sensitized solar cells (DSSCs). Although use of one dimensional structure provides the enhanced photoelectrical performance, it tends to reduce the adsorption of dye on the TiO2 surface due to decrease of surface area. To overcome this problem, we investigate the effects of TiCl4 treatment on DSSCs which were constructed with composite films made of TiO2 nanoparticles and TNTs. To find optimum condition of TNTs concentration in TiO2 composites film, series of DSSCs with different TNTs concentration were made. In this optimum condition (DSSCs with 10 wt% of TNT), the effects of post treatment are compared for different TiCl4 concentrations. The results show that the DSSCs using a TiCl4 (90 mM) post treatment shows a maximum conversion efficiency of 7.83% due to effective electron transport and enhanced adsorption of dye on TiO2 surface. [ABSTRACT FROM AUTHOR]

CdS/CdSe quantum-dot sensitized solar cells (QDSCs) were fabricated from ZnO nanorods deposited on fluorine-doped tin oxide (FTO) substrates via the application of polysulfide redox reactions and a CuS counter electrode. In the present study, a TiO2 compact layer was used to suppress the recombination process. Typically, a TiO2 compact layer prevents direct contact between the FTO and electrolyte. The TiO2 compact layer with optimal thickness was fabricated by varying the soaking time in a TiCl4 solution. In addition, the morphology and influence of the compact layer on the interface between the FTO/electrolyte were analyzed. [ABSTRACT FROM AUTHOR]

Highlights: [•] Nanoconfined 2LiBH4–MgH2–0.13TiCl4 was simply prepared by solution impregnation and melt infiltration. [•] Up to two times faster desorption kinetics as compared with nanoconfined 2LiBH4–MgH2. [•] Significant low onset dehydrogenation temperature (T= 140°C). [•] New reactive phase formations during de/rehydrogenation. [ABSTRACT FROM AUTHOR]

Abstract: A new method has been developed for the preparation of α,β-unsaturated carboxylic acids and corresponding esters with (E)-stereoselectivity via the TiCl4-mediated olefination of aldehydes. The method, which uses readily available acetic acid or its alkyl esters as active methylene partners, is more flexible and complementary to conventional routes in the preparation of (E)-cinnamic acid derivatives. [Copyright &y& Elsevier]