Peroxotitanium Complex Research Articles

Artificial Photosynthesis: Visible Light-Activated TiOCl<sub>2</sub>/2-Phenyl Indole Complexes for Atmospheric CO<sub>2</sub> and H<sub>2</sub>O Capture and Long-Chain Organic Products Generation

We present a novel self-organized chemical "living" system that mimics natural photosynthesis by capturing CO2 and H2O from the atmosphere at ambient conditions. This system autonomously reduces CO2 with H2O protons to produce long-chain aliphatic oxygenated products. Starting with 2-phenyl indole (PI) complexes with TiCl4, the hydrolyzed complexes react with CO2 to form organotitanium carbonates. The 2:1 PI/TiCl4 complex was found to be the most effective. Key findings include: Photocatalytic Reduction: Visible light reduces TiIV to TiIII and TiII, forming peroxotitanium complexes and releasing OH radicals. CO2 Reduction: CO2 is reduced to CO, H2CO, and CH3OH, which couple to form HOCH2CH2OH. Organic Compound Synthesis: The system generates oxygenated organic compounds with carbon chains from C2 to C16. Ligand Exchange: The PI ligand exchanges with donor molecules, forming adducts involved in the photocatalytic process. PI Oligomerization: Contributes to the formation of PI oligomers. These processes were monitored using matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) spectra, proton and Carbon-13 nuclear magnetic resonance (13C NMR), and infrared (IR) spectra, identifying over two dozen intermediates and products. This system offers a prototype for new applications with potential improvements using other metals and ligands.

Stoichiometric Study on Ion Composition of a Precursor in Chemical Bottom-Up Synthesis for Peroxo-Titanate.

Layered alkali titanates of the lepidocrocite type are gaining enormous interest in various fields owing to their unique properties. These materials are mainly synthesized through a hydrothermal alkali treatment. However, this method uses a highly concentrated alkali solution, which has high environmental impacts and is therefore unsuitable for mass synthesis. Herein, we propose an efficient method for the large-scale synthesis of layered sodium titanate structures (Na2-x H x Ti2O5) using a recently reported bottom-up chemical process. The effects of the Na:Ti molar ratio in the peroxo-titanium complex ion precursor on the products are investigated through stoichiometric calculations for a molar ratio range of 10:1-1:1. The optimal ratio for the complete ionization of TiH2 (which is the starting material) to form the peroxo-titanium complex ion is found to be 1.1:1. The amount of alkali raw material required is 99.6% lower than that required in the traditional hydrothermal method. The crystal structures and morphologies of the samples are almost identical regardless of the Na:Ti molar ratio. The precursor-derived peroxo bonds narrow the energy band gaps of the layered titanates even when the amount of titanium ions dissolved in the precursor increases. The proposed method is not only an efficient synthetic route for mass production but also has potential applications in the development of photofunctional materials.

Development of Eco-Friendly Ag Embedded Peroxo Titanium Complex Solution Based Thin Film and Electrical Behaviors of Resistive Random Access Memory

Development of Eco-Friendly Ag Embedded Peroxo Titanium Complex Solution Based Thin Film and Electrical Behaviors of Resistive Random Access Memory

Ti compound coating of carbonyl iron particles with controlled surface conditions using a peroxotitanium acid solution for stable magnetic particles

The surface coating of carbonyl iron particles (CIPs) deposited under various surface conditions was examined using a peroxotitanium acid (PTA) solution including H2O2 to obtain highly stable magnetic particles. Upon adsorption on the CIP surfaces, peroxotitanium complexes dehydrated and transformed into TiO2 with hydroxides (TiO2–OH), and the coating morphology significantly changed depending on the surface conditions of the CIPs. The volatile surface impurities that remained on raw CIPs inhibited the adsorption of the complexes, leading to insufficient coating. As oxidation treatment using a boric acid aqueous solution was performed to examine the effects of surface oxides on the coating, the treatment increased the oxide layer thickness and specific surface area of the raw CIPs. During the coating of oxidized CIPs, active surfaces were dissolved in a PTA solution, and γ-FeOOH plate particles were redeposited on the particle surfaces because H2O2 remaining in the PTA solution initially oxidized the active surfaces and then depleted. The results indicated that the treatment with the PTA solution was not suitable for oxidized CIPs with increased specific surface area. A simple dry treatment under vacuum conditions decreased surface impurities on raw CIPs without increasing their specific surface area; consequently, their surfaces were uniformly and sufficiently coated with TiO2–OH. The uniform surface coating decreased the saturation magnetization of the CIPs by only 0.98% and improved their oxidation onset temperature from 369.8°C to 437.1°C, making them suitable for practical use.

Electrochemical deposition of hydrothermally pretreated TiO2 on aluminium substrate through the formation of peroxotitanium complex and their application towards visible light assisted photocurrent generation

Herein, we report a novel method for the electrochemical deposition of TiO2 on Al substrate through the formation of peroxotitanium complex without any post heat treatment process. The alkaline treated titanium precursors were used as an electrolyte and TiO2 was deposited onto aluminium substrate by both cathodic reduction and electrophoretic deposition through the formation of peroxotitanium complex. The electrodeposition process was optimized by varying the pH, concentration of the electrolyte, deposition voltage, time and area of the electrode respectively. The optimized condition to obtain a maximum yield is as follows: voltage (4.5 V), time (2.5 h), pH (5) and area of the electrode 3 × 3 cm2. The deposits were then characterized using various material characterization techniques such as high-resolution transmission electron microscopy (HR-TEM), scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD) and Raman spectroscopy respectively. The morphological analysis showed the deposition of nanocrystalline TiO2 with irregular morphology on Al substrate. The AFM revealed a non-uniform deposition of TiO2 with high surface roughness (average roughness: 44.60 nm). The XRD pattern and Raman spectrum confirmed the presence of anatase phase of TiO2. The obtained TiO2 were then subjected to photoelectrochemical studies by coating over an ITO electrode. The nanocrystalline TiO2 showed excellent photocurrent response which could be due to the short hole retrieval and fast electron transport across the electrode-electrolyte interface. The proposed method can be promising towards the industrial application for the extraction and recovery of TiO2 from the mineral ore residues and spent mining waste.

Simultaneous electrochemical determination of uric acid and hypoxanthine at a TiO2/graphene quantum dot-modified electrode.

A TiO2/graphene quantum dots composite (TiO2/GQDs) obtained by in situ synthesis of GQDs, derived from coffee grounds, and peroxo titanium complexes was used as electrode modifier in the simultaneous electrochemical determination of uric acid and hypoxanthine. The TiO2/GQDs material was characterized by photoluminescence, X-ray diffraction, Raman spectroscopy, high-resolution transmission electron microscopy, and energy-dispersive X-ray mapping. The TiO2/GQDs-GCE exhibits better electrochemical activity for uric acid and hypoxanthine than GQDs/GCE or TiO2/GCE in differential pulse voltammetry (DPV) measurements. Under optimized conditions, the calibration plots were linear in the range from 1.00 to 15.26 μM for both uric acid and hypoxanthine. The limits of detection of this method were 0.58 and 0.68 μM for uric acid and hypoxanthine, respectively. The proposed DPV method was employed to determine uric acid and hypoxanthine in urine samples with acceptable recovery rates.

Yellow TiO2 from titanium peroxo complexes: Verification of the visible light activity and a rational enhancement of its photocatalytic efficiency

It is widely believed that colored TiO2 materials (yellow, blue, black, violet, etc.) are visible-light active photocatalysts. In this article, we verify this claim with respect to the yellow TiO2 photocatalyst that has been synthesized using peroxo-titanium complexes formation route. The surface oxygen species, the electronic structure, the photoelectrochemical properties, and the photoactivity of yellow TiO2 have been investigated. FT-IR and XPS analysis confirms the presence of surface peroxo-species that caused the yellow color. Spectroelectrochemical measurements confirmed the absorption of violet light (400–430 nm). The reduced band gap energy (3.05 eV) has resulted from the anodic shift of both conduction and valence band edges by 0.30 and 0.15 eV, respectively. However, the wavelength-dependent photocurrent generation by yellow TiO2 in the presence of oxygen and under deaerated conditions proved that it does not contribute to the photoactivity enhancement in the visible region (λ > 400 nm). The proposed mechanism has shown that although the driving force at the oxidation side is theoretically improved, the reduction counterpart is parallelly weakened and the photoinduced electrons cannot efficiently reduce regular electron acceptors in aqueous systems (e.g., O2, H2O). Adding a low amount of a stronger electron acceptor (e.g., H2O2) into the system provides extra HO• radicals through the reductive mechanism. At higher concentrations of H2O2, the oxidation of H2O2 is more favorable. The hydroxylation of terephthalic acid via the oxidative and reductive pathway along with the bleaching of Congo Red indicates improved photocatalytic activity due to enhanced hydrogen peroxide activation. Although yellow TiO2 is active only upon UV light irradiation, this paper reports how to boost the photocatalytic activity of this material.

Determination of prostatic fluid citrate concentration using peroxidase-like activity of a peroxotitanium complex

There have been developed many kinds of methods for detecting citrate in body fluids since citrate is very important physiologically and biochemically. In particular, determination of citrate concentration in prostatic or seminal fluid is useful in early diagnosis of prostate cancer. Recently, a peroxotitanium complex prepared from titanium tetrachloride and hydrogen peroxide has been shown to have peroxidase-like activity which is greatly inhibited by some hydroxyalkanoic acids. Hence, we established a method for determining citrate concentration in prostatic fluid using selective inhibition of citrate on the catalytic activity of the peroxotitanium complex.

Photodegradation and oxidizing action of peroxotitanium complex film

Photodegradation and accompanying oxidizing action of peroxotitanium complex (PTC) film were investigated, which made from PTC aqueous solution containing 61.3 mol % peroxo groups (O-O) to total Ti. The apparent activation energy (Ea) of the PTC degradation was revealed to be 132 kJ·mol−1 (λ = 905 nm), according to Arrhenius plot of the degradation rate constant of PTC aqueous solution with microwave hydrothermal treatment at 100–180 °C. The PTC films were slowly decomposed by light irradiation of UV lamp, visible light LED or light bulb, and simultaneously oxidatively decomposed methylene blue dissolved in water. The oxidation reaction occurred even under the light of long wavelength around 900 nm closed to the Ea. Furthermore, the utilization efficiency of active oxygen generated by the photodegradation to the oxidation reaction of acetaldehyde gas was estimated to be 66 and 80 % under UV light (2.00 mW·cm−2) and LED visible light (1.50 mW·cm−2), respectively.

TiO2/g-C3N4 Visible-Light-Driven Photocatalyst for Methylene Blue Decomposition

In this work, graphitic carbon nitride (g-C3N4)/titanium dioxide (TiO2) nanoparticles with heterostructures were synthesized in situ from a mixture of melamine and peroxo-titanium complexes in a calcination process. The TiO2 nanoparticles are well-dispersed on the g-C3N4 nanosheets. The prepared TiO2/g-C3N4 composites have a heterostructure and excellent photocatalytic activity for decomposing methylene blue (MB) under visible light irradiation. The as-obtained g-C3N4 embroiled with TiO2 has a much larger surface area than its components (66.7 and 6.6 m2·g−1 for TiO2 and g-C3N4 against 95.5–143.8 m2·g−1 for the composite, respectively). It enhances the separation of photo-generated charge carriers. The TiO2/g-C3N4 photocatalytic degradation of MB was investigated in aqueous heterogeneous suspensions. The experimental kinetic data for the photocatalytic process follow the pseudo-first-order kinetic model. Furthermore, TiO2/g-C3N4 retains high photocatalytic activity after four reaction cycles. In addition to prompt removal of the color, the TiO2/g-C3N4 photocatalyst can oxidize MB almost completely to final oxidation products. The pathway of MB decomposition was also addressed. Additionally, the TiO2/g-C3N4 photocatalytic system was employed to eliminate other typical organic pigments, such as malachite green, methyl blue, and methyl red. The TiO2/g-C3N4 material, with remarkable dye degradability, is a promising catalyst in industrial textile treatment and can find applications in light-harvesting systems.

Electrochemical preparation method of titanium dioxide on FTO

Cathodic electrodeposition of aqueous peroxo-titanium complex solution on fluorine doped tin dioxide (FTO) covered glass produced nanocrystalline amorphous and crystalline titanium dioxide. X-rays were used to examine the surface structures, which shows that heat treatment made a gradual crystallization of the deposits to the anatase form meanwhile the non-heated deposits present amorphous phase. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) and atomic force microscopy (AFM) permit to investigate the morphological aspect of the deposits, which display a good adherence and a nanoparticulate grain size. The UV-Visible spectroscopic investigation technique reveals the better transparency aspect of the annealed films than the non-heated deposits. Ac impedance spectroscopy confirms the electrical conductivity of both deposits with more important activity for the non-heated deposits.

Electrical Properties of TiN/TiO2/FTO Resistive Random-Access Memory Based on Peroxo Titanium Complex Sol Solution by Heat Treatment

Electrical Properties of TiN/TiO2/FTO Resistive Random-Access Memory Based on Peroxo Titanium Complex Sol Solution by Heat Treatment

Peroxidase-like activity of a peroxotitanium complex and its inhibition by some hydroxyalkanoic acids

A peroxotitanium complex (PTC) catalyses the oxidation of OPD by H2O2 while the catalyst stability depends on pH, temperature, and concentrations of H2O2 and catalyst. And the PTC catalysis is effectively inhibited by some hydroxyalkanoic acids.

A facile bottom-up method for synthesis of peroxo-potassium titanate nanoribbons and visible light photocatalytic activity derived from a peroxo-titanium bond.

Low-dimensional titanate nanostructures are gaining attention as a promising material for various photocatalytic applications. However, these conventional titanium oxide-based materials cannot utilize visible light because of their wide bandgap, and their synthesis generally requires high-alkali (10 mol L−1) and high-temperature (160–200 °C) conditions. Here, we report facile bottom-up synthesis for the visible light-activated peroxo-titanate nanoribbon (PTNR). The use of the peroxo-titanium complex ion containing the potassium ion as a precursor can induce the formation of a layered potassium titanate structure (K2−xHxTi2O5) based on the self-organization reaction between titanium complex ions and potassium ions under mild synthetic conditions (0.29–4.39 mol L−1 KOH, 100 °C). Furthermore, the requirement of potassium ions in the formation of layered potassium titanate was stoichiometrically examined. The layered titanate crystals could be grown anisotropically, which depended on the radius of the cation used. Our results newly revealed that the larger radius of the interlayer cation promotes anisotropic crystal growth. As a result, in the case of the potassium base, a nanoribbon structure with a higher aspect ratio and larger specific surface area than those of lithium and sodium bases was formed. The formed peroxo-titanium functional groups significantly reduced the bandgap of titanate to 2.64 eV. In a photocatalytic decolorization test, the PTNR showed excellent photocatalytic performance based on the large surface area and enhanced light absorption in the visible light range while still performing well under UV light. These findings show not only that the proposed synthetic process has a low environmental impact but also that it contributes to the development of highly functionalized materials for photochemical applications.

Water-soluble peroxotitanium complex: A novel strategy to prepare Fe2O3/Fe2TiO5 photoanode with enhanced water oxidation

The construction of Fe2O3/Fe2TiO5 heterostructure has been proven as an effective strategy to improve the photoconversion efficiency of hematite, however its controllable synthesis is still a great challenge. In this study, by performing a comparative investigation on two distinct Ti precursors, a novel, convenient, and low-cost approach for fabricating efficient Fe2O3/Fe2TiO5 photoanodes is developed. It clearly demonstrates that the adoption of typical TiCl4 precursor leads to a Fe2O3/TiO2 composite with a lower PEC activity, while a core-shell Fe2O3/Fe2TiO5 heterostructure is built via using the stable and water-soluble peroxo-titanium complex (PTC) precursor. The as-fabricated photoanode exhibits a comparable photocurrent density of 2.51 mA/cm2 at 1.23 V vs. RHE to most of Fe2O3/Fe2TiO5 photoanodes in literatures. Based on various characterizations, the significant enhancement in PEC performance can be attributed to the largely increased donor density and the formation of Fe2O3/Fe2TiO5 core-shell heterostructure, which effectively facilitate the charge separation and transport in the bulk and surface of photoanode. This work provides a new idea for fabricating high-efficient Fe2O3/Fe2TiO5 photoanodes.

Metal-doped titanium oxide films for suppressing potential-induced degradation of photovoltaic modules

Titanium oxide films were prepared from peroxotitanium complex aqueous solution containing a peroxo complex of vanadium, molybdenum or tungsten of 2, 5, 10 mol % by heating at 200 °C for the purpose of suppressing the photocatalytic activities that may be developed by crystallization during long-term use as a prevention film against potential-induced degradation (PID) of crystalline silicon (c-Si) photovoltaic (PV) module. The films containing those dopants crystallized to anatase by hydrothermal treatment at 100 °C for 15 h as an acceleration test, but hardly showed any photocatalytic activity. According to the lattice constants, X-ray photoelectron spectroscopy analyses and UV–visible light reflection spectra, it was estimated that vanadium (V), molybdenum (VI) and tungsten (VI) were substituted with titanium (IV) in titanium oxide heated at low temperature of 200 °C. The titanium oxide films containing the dopants of 2 mol % were coated at 200 °C onto the rear side of front cover glass with 200 nm thickness. No significant PID was observed in the c-Si PV modules based on the film-coated glass by a PID test by applying −1000 V at 85 °C for 2 h.

Preparation of the CaAl2O4:Eu2+, Nd3+/TiO2 composite by peroxo titanium complex solution and its photodegradation of methylene blue

Preparation of the CaAl2O4:Eu2+, Nd3+/TiO2 composite by peroxo titanium complex solution and its photodegradation of methylene blue

Synthesized TiO2 Mesoporous by Addition of Acetylacetone and Graphene for Dye Sensitized Solar Cells

This study mixed acetylacetone (Acac, 1, 2, and 3 mL) and graphene powder (GP, 0 wt.%, 0.001 wt.%, 0.003 wt.% and 0.005 wt.%) with TiO2 mesoporous (TiO2 powders: 20 g and particle size ~30 nm) to enhance the optoelectronic performances of dye sensitized solar cells (DSSC). Sponge-like structure TiO2 mesoporous layers is a requirement for obtaining high efficiency DSSC, which ia synthesized by spin-coating techniques. The dense TiO2 blocking layer (using peroxo-titanium complex) has a uniform, dense structure and completely adheres to the substrates to avoid charge recombination. The X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses of the TiO2 films display the anatase type phase with preferred orientation along the (101) direction. After being ball milled, the TiO2 mesoporous particle size almost remains unchanged. For mixing the Acac with TiO2, the Raman intensity relatively increased, and the band gap energy (Eg) value decreased from 3.223 eV (for pure TiO2) to 3.076 eV (for 2 mL Acac). Raman spectroscopy is used to evaluate the GP elements. It can be seen the intensity ratio (ID/IG) and (I2D/IG) was enhanced when the GP concentration increased. Using mixed Acac 2 mL and GP 0.003 wt.% with a TiO2 mesoporous, led to increases in the open circuit voltage (VOC), short circuit current density (JSC) and fill factor (FF). If a fluorine-doped tin oxide is used instead of an indium tin oxide glass substrate, the photovoltaic efficiency of DSSC increases from 5.45% to 7.24%.

Development of eco-friendly thin film manufacturing process using poeroxo titanium complex solution and potential for resistive random access memory

Here we report on the development of thin film manufacturing processes based on new and sustainable green solutions. We focused on utilizing green based surface solutions. The peroxo titanium complex (PTC) solution-based thin film fabrication method used does not require additional heat treatment and complex processes to remove organic matter. Conditions suitable for thin film fabrication were derived through optimization of precursor concentration and reaction temperature. As a result of I-V test of TiN/TiO2/FTO samples fabricated by applying this technology, it has been proven that it can operate as a resistive random-access memory (RRAM). The measured I-V curve suggests that TiN/TiO2/FTO RRAM exhibits bipolar resistive switching (RS) characteristics through the formation of oxygen vacancy (Vo) filament conduction paths. We also used the double logarithmic plot analysis to confirm that the dominant conduction mechanism of the device is the space charge limited conduction (SCLC) model.

Bifunctional TiO2/CeO2 reactive adsorbent/photocatalyst for degradation of bis-p-nitrophenyl phosphate and CWAs

TiO2/CeO2 nanocomposites were prepared by simple refluxing of peroxo titanium and cerium complexes in water at ambient air and they were used for degradation of several organophosphorus compounds (OPC). The combination of high surface reactivity of ceria with photoactivity of titania led to i) rapid reactive adsorption of bis-p-nitrophenyl phosphate (BNPP) forming p-nitrophenyl phosphate (NP) and ii) subsequent photo-induced degradation of both BNPP and NP. The composites were also three and four times more efficient for rapid degradation of chemical warfare agents (CWAs) soman and VX in nonane compared to bare ceria and titania, respectively. The strong interaction of Ti with Ce within the composites led to the formation of Ce3+ and Ti<4+ states, reduction of titania crystallite size, change of acid-base and surface properties and synergetic effects that are all responsible for highly improved degradation efficiency of these bifunctional nanocomposites with considerable potential of application for abatement of various toxic compounds.