Titanic Acid Research Articles

MXene-derived titanic acid with an ultralow-potential as a promising anode for aqueous zinc-ion batteries

Replacing Zn metal with intercalated materials as the aqueous zinc-ion batteries (AZIBs) anode is an effective strategy to solve serious zinc dendrites problem. MXene-based derived materials combine the advantages of both derivatives with excellent electrochemical activity and MXene with high electrical conductivity. Here, we report an in situ derived strategy for synthesizing H2Ti3O7−MXene from common Ti3C2 MXene by one-step hydrothermal process with simultaneous alkalization and oxidation, followed by ion-exchange reaction. It is experimentally verified that H2Ti3O7 −MXene exhibits an extremely low charging voltage of only 0.25 V, which has a satisfactory potential for AZIBs anodes. Through characterization analyses, H2Ti3O7−MXene nanoflowers consist of countless connectively interlaced and entangled nanoribbons, which shorten the ion diffusion path and accelerate Zn2+ diffusion kinetics. The synergistic effect between H2Ti3O7 and MXene enables H2Ti3O7−MXene to achieve efficient and reversible Zn2+ (de)intercalation. Specifically, at 0.10 A g−1, the specific capacity of 61.20 mAh g−1 is achieved and no significant discharge specific capacity decline occurs at 0.60−2.00 A g−1. The assembled zinc ion full-cell (ZnxMnO2//H2Ti3O7−MXene) shows the excellent cyclic stability and good coulombic efficiency during 600 GCD cycles. This work proves the feasibility of MXene-based derivatives for AZIBs anode and sheds light on developing efficient intercalated MXene derived anodes.

Elemental sulfur supported on ultrathin titanic acid nanosheets for photocatalytic reduction of CO2 to CH4

The photocatalytic reduction of CO2 into energy-intensive hydrocarbon fuels is promising to solve environment and energy issues. Here, elemental sulfur supported on ultrathin titanic acid nanosheets (S/HTO) heterostructure is designed and synthesized by loading different weight contents of elemental S on HTO nanosheets via a simple in-situ disproportionation-assembly process. The as-designed S/HTO heterostructure not only enhances light absorption and facilitates CO2 adsorption, but also significantly promotes the interfacial charge transport, and suppresses the recombination of photogenerated charge carriers. As a consequence, the as-prepared S/HTO heterostructure exhibits enhanced performance in photocatalytic CO2 reduction under simulated solar light illumination. A CH4 yield rate of 1.92 μmol h−1 g−1 is obtained over the optimal 15S/HTO composite without the using of cocatalyst and sacrificial agent. The photoactivity is 5.4-fold and 23-fold larger than that of HTO nanosheets and blank S, respectively. In addition, the S/HTO hybrid composite also presents high stability for the production of CH4.

In situ topotactic preparation of porous plate-like Li2ZnTi3O8 as the lithium-ion batteries anode for enhancing electrochemical reaction kinetics and Li+ storage

Spinel Li2ZnTi3O8 (LZTO) is widely studied in the field of anode materials for lithium-ion batteries (LIBs) in recent years because of its stable cycling performance, no volume expansion and higher theoretical capacity than that of Li4Ti5O12. In this work, porous plate-like LZTO is synthesized via a simple in situ topological reaction with layered Titanic acid as the precursor. Due to its special morphology, a large amount of pseudocapacitance is introduced for lithium-ion storage in conjunction with the intercalation reaction. This co-storage mode allows more Li+ to be stored, resulting in the plate-like LZTO getting the highest capacity in the LZTO-based anode. It shows a reversible capacity of 338 mAh/g at 0.1 A/g and maintains excellent performance in long cycle tests under high current density (208 mAh/g after 1000 cycles at 1 A/g and 118 mAh/g after 2000 cycles at 5 A/g). In terms of electrochemical reaction kinetics, the two-dimensional plate structure provides a flat path for electron transport and the micropores on its surface provide many fast channels for the Li+ diffusion. Its simple synthesis method and excellent electrochemical properties prove that it has a great potential to become the new generation of anode materials for LIBs.

Hydrothermal preparation of high purity TiO2 from industrial metatitanic acid by response surface methodology

The response surface methodology of Box Behnken design was used to investigate the effects of hydrothermal conditions on the high purity TiO2 preparation from industrial metatitanic acid. The method had a good fitting result in the prediction model, and the effects could be calculated from a second-order polynomial equation. The hydrothermal conditions greatly affected the structure and purity for the metatitanic acid and rutile TiO2, influenced the process of nucleation and crystallization, grain growth, polymerization, agglomeration and aggregation, further improved the particle size distribution, structure and surface adsorption capacity of metatitanic acid, reduced the adsorption of impurity ions, and finally improved the purity of TiO2. The variables such as hydrothermal temperature, slurry concentration and hydrothermal time had synergistic effects, and the effects of hydrothermal time were larger than the other two. The verification experiments confirmed that the predicted values could be achieved at 99.99% under the optimal hydrothermal conditions.

Investigation on the structure evolution of rutile TiO2 during calcination of mixed-salt-treated metatitanic acid

The calcination of metatitanic acid is the key process of rutile TiO2 production by sulfuric acid method, and the calcination quality affects the crystal morphology, particle size and particle size distribution, and finally pigment properties of rutile TiO2. Mixed salts treatment assisted calcination was an efficient process to solve the basic scientific problems of high calcination temperature and long calcination time. In this study, mixed ZnO-P2O5 treatment agent was adopted in calcinating metatitanic acid to produce rutile TiO2, and the mixed salt treated metatitanic acid was annealed at various temperatures so as to investigate the structure evolution. Characterizations of the as-prepared TiO2 samples were carried out using scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) to investigate the function of ZnO and P2O5 during the metatitanic acid calcination process. The results demonstrate that the surface oxygen vacancies resulting from the substitution of Ti4+ with Zn2+ can promote the anatase–rutile transformation while chemically adsorbed phosphate can reduce the sintering degree of TiO2 particles, resulting in a uniform particle size distribution.

Rapid exfoliation of H2O2-intercalated layered titanate and visible-photocatalytic hydrogen production performance of exfoliated nanosheet

Usually, it takes 3–7 days to exfoliate the layered titanic acid H1.07Ti1.73O4 (HTO) into Ti1.73O41.07– (TO) nanosheet. The H2O2 molecules can easily enter into the interlayers of the HTO crystal to form the H2O2 intercalated HTO. The H2O2 intercalation can achieve rapid exfoliation of HTO. It takes 1 h to exfoliate into a yellow H2O2-modified TO nanosheet, which has a wide absorption wavelength range and a narrow band gap. Moreover, such 2D nanosheet has a large specific surface area and a large number of reactive sites. And such yellow H2O2-modified TO nanosheet displays some visible photocatalytic hydrogen production performance. When the H2O2-TO nanosheet is loaded with Ni(OH)2, the sample can show a higher photocatalytic hydrogen production performance. The maximum photocatalytic hydrogen production rate of the Ni(OH)2-H2O2-TO catalyst is 32.48 μmol h−1 g−1, which is 4.1 and 1.9 times higher than that of H2O2-TO and Pt-H2O2-TO. This is due to the formation of a type II heterojunction between the H2O2-TO nanosheet and Ni(OH)2. This heterojunction can achieve the effective separation of photogenerated carriers.

Phase change and crystal growth of TiO2 in metatitanic acid

The transformation of anatase titanium dioxide (TiO2) to its rutile form generally occurs above 600 °C. The anatase to rutile transformation is influenced by the factors such as heating temperature, heating time and the states of particles of anatase TiO2. In the calcination of metatitanic acid, the phase transformation of anatase is a key step to form rutile TiO2 particles with desirable morphological and pigmentary characteristics. However, the precise roles of temperature and time are not clear in the construction of so called calcination intensity for promoting the anatase-rutile transformation to form pigmentary TiO2 from metatitanic acid. Here we show how the temperature and time have affected the anatase to rutile transformation and the crystal growth of metatitanic acid during the calcination. Through thermal analysis, XRD and SEM measurements, we found that the rutilization in metatitanic acid shows a similar growing trend in the most of phase transformation process. However, the trend of the transformation undergoes an abrupt change when rutilization is approaching to its completion. The changes of the morphology of metatitanic acid are related to the coarsening of the particles in the metatitanic acid during the calcination. Our results demonstrate that anatase to rutile transformation and coarsening of particles are affected by the heating temperature and heating time and the growth of TiO2 particles can be controlled through calcination intensity.

Rutile TiO2 Production: Optimization of Microwave Calcination of Metatitanic Acid Using Response Surface Methodology

AbstractRutile TiO2 was prepared by microwave calcination of metatitanic acid. A quadratic regression model for the conversion to rutile TiO2 was developed by response surface methodology (RSM), to investigate the effects of the calcination temperature, the calcination time, the sample mass, and their interactions on the conversion rates. Within the scope of the experiments, only the calcination temperature and time had significant effects on the rutile TiO2 conversion. Under the optimized conditions (866 °C, 61 min, 58 g), the predicted rutile TiO2 conversion was 99.91 %, approaching the actual conversion (99.44 %). Thus, the optimization by RSM of microwave calcination of metatitanic acid for the preparation of rutile TiO2 is a feasible approach to achieving a more efficient TiO2 production process.

Study on Continuous Hydrolysis in a Microchannel Reactor for the Production of Titanium Dioxide by a Sulfuric Acid Process.

The development of a continuous hydrolysis process of titanium sulfate is an innovation to the traditional production process of titanium dioxide by the sulfuric acid process. In the experiment, a microchannel reactor was designed, and the hydrolysis rate of titanium sulfate, the particle size, and particle size distribution of metatitanic acid agglomerates were used as indicators to investigate the effect of operating conditions on the continuous hydrolysis of titanium sulfate. The results have shown that as the amount of dilution water increased, the hydrolysis rate of titanium sulfate decreased, and the particle size of primary aggregates of metatitanic acid increased from 39 to 54 nm. As the alkali mass concentration of dilution water increased, the hydrolysis rate of titanyl sulfate increased, and the particle size of primary aggregates of metastatic acid first decreased and then increased, and the particle size range was 40–48 nm. As the flow rate increased, the hydrolysis rate of titanyl sulfate increased, and the particle size of primary aggregates of metatitanic acid dropped from 59 to 43 nm. Compared with the batch hydrolysis operation, the continuous process has stronger anti-disturbance ability, significantly shorter operation time of the reaction section, and narrower particle size distribution of the product metatitanic acid.

Morphological, spectral and toxicological features of new composite material of titanium nanodioxide with nanosilver for use in medicine and biology

The results of this study indicate that titanium dioxide nanoparticles (nano-TiO2) possess adsorptive, photocatalytic, bactericidal, virucidal and fungicidal properties, which are used in antibacterial coating, for air and water disinfection. In parallel with studies of the physicochemical characteristics of titanium dioxide, its toxicological assessment was carried out to prevent possible harmful effects on humans and the biosphere objects, followed by an assessment of the nano-TiO2 hazard class. To enhance these useful properties of nano-TiO2, nanopowders of titanium dioxide and a composite of titanium dioxide were synthesized with a silver (nano-TiO2 /Ag) by way of chemical precipitation of metatitanic acid adding silver nitrate to the composite at 500-600°C. It was stated that the synthesized nanostructures have the following characteristics: anatase crystal structure of TiO2 (anatase, rutile, brookite – natural crystalline modifications of TiO2), the size of Ag nanoparticles is 35-40 nm, TiO2 – 13-20 nm. Nanocomposite has surface defects of the crystal lattice (oxygen vacancies, impurities, excess electrons or holes), silver nanoparticles are localized on the surface of anatase TiO2, which increases adsorptive, photocatalytic, biological and specifically antibacterial properties of the composite material nano-TiO2/Ag. According to the parameters of acute intraperitoneal toxicity, the studied nanocomposite anatase nano-TiO2/Ag was classified as a moderately dangerous substance (material). Nano-TiO2 and TiO2/Ag nanocomposites do not cause local irritation to the skin, yet have a mildly irritating effect on the mucous membrane of the eye, and are also characterized by a weak sensitization effect.

Investigation on process mechanism of a novel energy-saving synthesis for high performance Li4Ti5O12 anode material

Li4Ti5O12 (LTO) anode material demonstrates superior cycling performance due to its stable spinel structure and high lithiation/de-lithiation potential. Herein, a novel energy-saving solid-phase synthesis route for LTO has been successfully designed, employing the cheap industrial intermediate product of metatitanic acid (HTO) as titanium source. Through the in-situ Fourier transform infrared spectroscopy (FTIR) and ex-situ X-ray diffraction (XRD), it is revealed for the first time that the amorphous crystal structure of HTO is more conducive for the Li+ insertion, making it possible to prepare LTO at a relatively lower sintering temperature. Utilizing the dehydration carbonization reaction between glucose and sulfuric acid, an ingenious strategy of glucose pre-coating is adopted to avoid the generation of Li2SO4 impurity caused by the residual sulfuric acid on the surface of HTO, which meanwhile enhances the conductivity and inhibits the particle growth of LTO. The obtained ALTO@C anode material consequently exhibits excellent electrochemical performance that 132.0 mAh g−1 is remained even at 20 C, and ultra low decay rate of 0.015% per cycle is achieved during 1000 cycles at 2 C. Remarkably, LiCoO2//ALTO@C full cell delivers conspicuous low-temperature property (130.7 mAh g−1 at 0.5 C and almost no attenuation after 300 cycles under −20 °C).

Synthesis and Analysis of Anthracene –Lead Titanate composites by Solid State Method

The composition of Anthracene and Lead Titanate is prepared using Solid State method. Anthracene is a solid polycyclic aromatic hydrocarbon (PAH) of formula C14H10, consisting of three fused benzene rings. It is a component of coal tar. Lead (II) titanate is an inorganic compound with the chemical formula PbTiO3. It is the lead salt of titanic acid. Lead (II) Titanate is a yellow powder that is insoluble in water. At high temperatures, lead Titanate adopts a cubic perovskite structure. The samples of Anthracene –Lead Titanate composites of suitable mixture ratio are prepared using Solid state method. Crystal structure of the calcined powders and als sintered ceramics were analysed using XRD(X-ray diffraction). The microstructure of the sintered ceramics has been investigated using SEM (scanning electron microscopy).

Characteristic of TiO2&Ag0 nanocomposites formed via transformation of metatitanic acid and titanium (IV) isopropoxide

Composite nanoparticles TiO2&Ag0 were synthesized by coprecipitationin a weakly alkaline medium in the presence of various precursors - metatitanic acid and titanium (IV) isopropoxide. Comparative study of TiO2&Ag0 included analysis of morphology (SEM), phase (XRD) and chemical compositions (EDS). The formation of anatase structures was confirmed at a relatively low concentration of silver (0–8 wt% for metatitanic acid and 0–4 wt% for Ti (IV) isopropoxide). An increase in the Ag fraction to 8 wt% led to the appearance of the Ti2O3 and β-TiO2 phases in the Ti(IV) isopropoxide system. The size distribution of primary particles is 8.3–10.6 nm (Ti(IV) isopropoxide system) and 12.3–14.0 nm (metatitanic acid system). The anatase lattice parameters decrease with Ag wt% increasing in Ti(IV) isopropoxide system and do not change for the metatitanic acid system. TG-DTA study showed the effects corresponding to the removal of structural water (210 °C), destruction of isopropoxide and combustion of organic matter (300–410 °C), crystallization of anatase (510 °C) and the anatase transformation into the rutile phase (720–760 °C), but in the presence silver, the anatase structure did not change to 1000 °C. Morphological study shows high crystallinity of both kinds of structures but less aggregative stability composites formed in the metatitanic acid solution. All type nanocomposites include four chemical elements – Ti, Ag, O, and Na as well as a small number of various admixtures - S or Cl and K depending on precursor species. At the same time, a relatively high concentration of argentum in the initial solution led to obtaining chemically pure composite nanoparticlesandcore&shell type structures.

Optimization of High Purity Tio2 Preparation from Industrial Metatitanic Acid by Hydrothermal Treatment with Response Surface Methodology

Optimization of High Purity Tio2 Preparation from Industrial Metatitanic Acid by Hydrothermal Treatment with Response Surface Methodology

Lithium Ion Battery Anode of Mesocrystalline CoTiO3/TiO2 Nanocomposite with Extremely Enhanced Capacity

Mesocrystalline materials consisting of nanocrystal subunit alignment with the same crystallographic orientation have a potential application as active materials for lithium ion battery (LIB) electrodes. In this study, a topochemical process was developed to synthesize mesocrystalline CoTiO3/TiO2 nanocomposites using a layered titanic acid H1.07Ti1.73O4 (HTO) precursor. The H2O2 treatment of HTO caused more Co2+ intercalation into the interlayer by the H+/Co2+ exchange reaction and the formation of a sandwich layered structure by stacking an HTO layer and a Co(OH)2–xx+ layer. This sandwich layered structure was topotactically transformed into a mesocrystalline CoTiO3/TiO2 nanocomposite by heat treatment at >600 °C. The selected area electron diffraction result suggests that the CoTiO3/TiO2 nanocomposite is constructed from [010]-oriented CoTiO3 nanocrystals and [110]-oriented rutile TiO2 nanocrystals. The electrochemical results indicate that the mesocrystalline CoTiO3/TiO2 nanocomposite exhibits an extremely enhanced anode capacity of about 400 mAh/g for LIB, which is 2 times higher than that of polycrystalline CoTiO3. The excellent anode performance can be ascribed to the high mobility of Li+ in the mesocrystalline nanocomposite and the synergistic effect of TiO2 nanocrystals in the nanocomposite by enhancing the cycling stability and electron conductivity.

One-step synthesis and its mechanism of potassium hexatitanate whiskers from potassium dititanate and metatitanic acid

The high price of potassium hexatitanate (K2Ti6O13) whiskers restricts its broad applications. The current production method is composed of complex processes and generates a large amount of wastewater. In this work, we propose a new one-step synthesis approach for producing potassium hexatitanate whiskers. Potassium dititanate and metatitanic acid are mixed at the ratio of TiO2/K2O = 4 and then calcined at 1000 °C to synthesize potassium hexatitanate whiskers. We used XRD, SEM, TG-DSC, and other characterization techniques combined with thermodynamic calculations to study the synthesis mechanism of such one-step process. The thermodynamic calculations show that the reaction free energy of K2Ti6O13 whiskers synthesized by this process is negative even at room temperature, confirming that this process has a higher reactivity than the conventional synthesis approach by K2CO3 and TiO2. Moreover, the melting of K2Ti2O5 at 916 °C provides a necessary environment for the crystal growth of K2Ti6O13 nanoparticles, which is the key to the preparation of K2Ti6O13 whiskers. This new synthesis approach will significantly reduce the producing cost of K2Ti6O13 whiskers, thereby expanding its applications.

Role of aluminum salt on thermal hydrolysis of titanyl sulfuric–chloric mixture acid solution

To make use of scrap perovskite titanium slag to produce metatitanic acid, a new method based on the high efficiency decomposition ability of sulfuric–chloric mixture acid (SCMA) has been proposed. Because Al is one of the most common elements existing in its raw state, Al 3+ has become the main impurity in titanium solutions after decomposition, which affects the performance of related products. Consequently, the role of Al on the thermal hydrolysis of Ti in the SCMA solution was investigated in this study. With the addition of Al 3+ , a lower hydrolysis ratio was obtained at a low reaction temperature (130 °C). Moreover, the particles of metatitanic acid displayed a ball-shaped morphology and narrow particle distribution with a D 50 of 1.4–2.0 μm. According to the crystal structures of Al 3+ , it is presumed that the priority order of ligand is SO 4 2 − > H 2 O > Cl − . The addition of Al 3+ increases the growth rate of the a - and b -axes but reduces the growth rate of the c -axis. The results presented here confirm the influence of Al 3+ in the control of nucleation and growth process during the hydrolysis to achieve qualified metatitanic acid products.

A study on the synthesis of coarse TiO2 powder with controlled particle sizes and morphology via hydrolysis

The hydrolysis of Ti(IV)-bearing acid solution to prepare titanic acid particles is a crucial step for the production of TiO2 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 TiO2 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.

Alkaline Co(OH)2-Decorated 2D Monolayer Titanic Acid Nanosheets for Enhanced Photocatalytic Syngas Production from CO2.

The difficulty of adsorption and activation of CO2 at the catalytic site and rapid recombination of photogenerated charge carriers severely restrict the CO2 conversion efficiency. Here, we fabricate a novel alkaline Co(OH)2-decorated ultrathin 2D titanic acid nanosheet (H2Ti6O13) catalyst, which rationally couples the structural and functional merits of ultrathin 2D supports with catalytically active Co species. Alkaline Co(OH)2 beneficially binds and activates CO2 molecules, while monolayer H2Ti6O13 acts as an electron relay that bridges a photosensitizer with Co(OH)2 catalytic sites. As such, photoexcited charges can be efficiently channeled from light absorbers to activated CO2 molecules through the ultrathin hybrid Co(OH)2/H2Ti6O13 composite, thereby producing syngas (CO/H2 mixture) from photoreduction of CO2. High evolution rates of 56.5 μmol h-1 for CO and 59.3 μmol h-1 for H2 are achieved over optimal Co(OH)2/H2Ti6O13 by visible light illumination. In addition, the CO/H2 ratio can be facilely tuned from 1:1 to 1:2.4 by changing the Co(OH)2 content, thus presenting a feasible approach to controllably synthesize different H2/CO mixtures for target applications.

Novel approach for high-efficiency recovery of titanium dioxide, hydrochloric acid, and organic solvents from titanium white waste acid

In this study, the recovery efficiency of titanium dioxide (TiO2), hydrochloric acid (HCl), and organic solvents in titanium white waste acid (TWWA) is investigated via distillation combined with the calcination method. After distillation under vacuum condition at −0.071 MPa for 60 min, the recovery of diisobutyl phthalate (DIBP), hexane (C6H14), ethanol (C2H5OH), and HCl reached up to 70%, 76%, 68%, and 21%, respectively. Moreover, the metatitanic acid (TiO(OH)2) concentration in TWWA thick slurry obtained at the end of vacuum distillation increased from 72.60 to 416.11 g/L. Anatase and rutile were harvested after 60-min continuous calcination of TWWA thick slurry at 600 °C and 900 °C, respectively, and the TiO2 content in rutile was as high as 93%. Based on these results, we believe that TiO2, HCl, and organic solvents can be efficiently recovered from TWWA via vacuum distillation and high-temperature calcination. This method realizes the reduction and resource utilization of TWWA and has the advantages of simple technological process and low treatment cost.