Titanium Butoxide Research Articles

Preparation of TiO2/graphene oxide and their photocatalytic properties at room temperature

TiO2/GO with different graphene oxide (GO) composite ratios were prepared by hydrothermal method and characterized by SEM, TEM, XRD, UV-vis, XPS, Raman and photocurrent. The results show that both TiO2 and GO/TiO2 crystal are anatase type. Part of GO is reduced to the reduced graphene oxide (RGO), properties of which are closer to that of graphene, when GO is prepared by hydrothermal reaction with butyl titanate. And such transformation is conducive to photoelectron transfer. Compared with pure TiO2, the composite TiO2/GO catalyst has a smaller grain size and a higher ratio of adsorbed oxygen/lattice oxygen, which is beneficial to the oxidation of NO. Moreover, lower band gap enhances the abilities of absorbing visible light and the photoelectron response over TiO2/GO catalyst. Therefore, the catalyst exhibits more excellent photocatalytic performance. The photocatalytic denitration performance of the composites was evaluated under visible light. When the GO composite ratio is 1.5%, the catalyst possesses the optimal photocatalytic denitration performance. When the ratio of ammonia to nitrogen is 1:1, the denitration efficiency can reach as high as 88.6%, which is 30% higher than that of self-made unmodified TiO2 and 40% higher than that of V-Ti-W catalyst. The anti-interference ability is significantly stronger than that of commercial V-Ti-W catalysts. It is concluded, from the mechanism analysis, that the oxidation rate of NO plays a key role in the process of photocatalytic denitration, and the presence of ammonia can accelerate the reduction of NO2.

Effect of hybrid TiO2 nanoparticles with controlled morphology on rheological properties of poly(styrene-co-acrylonitrile) nanocomposites

The variation of the nanoparticle’s morphology is an efficient way to tune the properties of polymer nanocomposite. Herein, the TiO2 nanoparticles were synthesized within the polymer templates. Molecular brushes with poly (acrylic acid)-block-polystyrene (PAA-b-PS) side chains were used as polymer templates, while four different particle precursors were applied to vary particles’ morphology, titanium (IV) 2-ethylhexanoate, titanium (IV) bis(ammonium lactato)dihydroxide, titanium (IV) isopropoxide and titanium (IV) butoxide. Although the synthetic conditions for generation of TiO2 were essentially the same, particles with varied morphology were obtained. Such hybrid systems containing the TiO2 nanoparticles loaded within polymer templates were introduced into poly (styrene-co-acrylonitrile) (SAN) and formed final composites with varied rheological properties. In SAN/TiO2@template composites, the solid nanometric phase of the hybrid particles TiO2@template acted as an active filler, generating mechanical reinforcement and affecting viscoelastic properties.

The Preparation of {001}TiO2/TiOF2 via a One-Step Hydrothermal Method and Its Degradation Mechanism of Ammonia Nitrogen.

{001}TiO2/TiOF2 photocatalytic composites with a high activity {001} crystal plane were prepared by one-step hydrothermal methods using butyl titanate as a titanium source and hydrofluoric acid as a fluorine source. X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), raman spectroscopy, N2 adsorption-desorption curve (BET), UV-Vis diffuse absorption spectroscopy (UV-Vis DRS), X-ray photoelectron spectroscopy (XPS), and fluorescence spectroscopy (PL) were used to evaluate the structure, morphology, specific surface area, optical properties, and photocarrier separation ability of {001}TiO2/TiOF2. Ammonia nitrogen was taken as the target pollutant, and the degradation performance of the catalyst was investigated. The results show that hydrofluoric acid improves the content of {001} crystal plane of TiO2 with high activity; it also improves the specific surface area and dispersion of the composite material and adjusts the ratio of {001}TiO2 to TiOF2 in the composite material to enhance the absorption capacity of the composite material and reduce the band gap width of the composite material. The degradation rate of ammonia nitrogen by 100 mg F15 is 93.19% when the initial concentration of ammonia nitrogen is 100 mg/L and pH is 10. Throughout the reaction process, the {001}TiO2/TiOF2 composite produces superoxide anion radical (·O2−) and hydroxyl radical (·OH) to oxidize NH3·H2O and generate N2 accompanied by a small amount of NO3− and NO2−.

Characterization and photocatalytic activity of TiO2 nanoparticles on cotton fabrics, for antibacterial masks.

The in-situ impregnation of two commercial cotton fabrics (lab coat and Indiolino) with TiO2 nanoparticles (TiO2-NPs) was carried out. For this, two commercial cotton fabrics were dipped in titanium isopropoxide, titanium butoxide and titanium tetrachloride solutions to the TiO2-NPs formation and in-situ TiO2-NPs impregnation on the cotton fabric surface by the sonochemical, hydrothermal and solvothermal methods, respectively. The impregnated fabrics were characterized by ATR-FTIR, SEM–EDS, Raman, UV–Vis, DRS and tension tests. The results showed the successful formation and impregnation of TiO2-NPs on both cotton fabrics. The leaching of TiO2-NPs from cotton fabrics was negligible after several washing cycles. The self-cleaning properties and antibacterial activity of TiO2-NPs functionalized cotton fabrics were assessed by photocatalytic and antibacterial tests. The photocatalytic activity was determined by the degradation of methylene blue dye under UV and solar irradiation. The materials showed good photoactivity, since MB was degraded up to 99% under solar and UV irradiations in 60 min. The bactericidal capacity of the TiO2-NPs on fabrics, evaluated in-situ by SEM, showed that Indiolino presented the best antibacterial properties against Escherichia coli and Bacillus pumilus.

Understanding the effect of polymer concentrations on the phase formation and activity of electrospun nanofibrous photocatalyst

One-dimensional titanium dioxide electrospun nanofiber have been extensively studied, it provides channels for quick charge transfer due to their long axial ratio, but as per the experiment reports the phase formation is not conclusive about the origin of the crystallinity of titanium oxide, nor about role of polymer amount. In this study, the effect of sacrificial polymer in the electrospun solution on Ti-O bonds breaking and on the arrangement of TiO6 octahedra was obtained for different titanium oxide phase formations. In particular, polymer-metal precursor plays the role of Magnéli phase formation at low temperature. The nanofibers were prepared at different titanium butoxide and polymer concentrations with the optimization of electrospinning parameters such as electric field strength, the flow rate of the electrospinning solution, the distance between the nozzle and the receiving drum collector, and the speed of the rotating collector. The effect of polymer concentration on the crystallinity and phase compositions was examined in detail. Surprisingly, the percentage of anatase phase was found to decrease with increasing the polymer amount with a fixed annealing temperature. The experimental results show that carrier polymer polyvinylpyrrolidone is not only involved in the fiber formation through chain entanglements but plays a significant role to control TiO6 octahedral configurations and connectivity. More polymers promote edge-sharing between TiO6 rather than corner-sharing. We demonstrate the efficient photocatalytic activity of the mixed phase TiO2 nanofiber in the photocatalytic degradation of Rhodamine B dye. A significant increase in the reaction rate was observed with the increase of the Titanium butoxide:polyvinylpyrrolidone ratio. It was found that 70% anatase and 30% rutile mixed phase TiO2 nanofiber catalysts exhibit optimum photocatalytic activity with rate constant values of 0.345 min−1. The mechanism relates to the interfacial charge carrier at the junction of anatase and rutile band alignment.

Synthesis of Zinc-Titanium Oxide Nanocomposites by Plasma Jet and Its Application to Photocatalyst

In order to synthesize the zinc-titanium (Zn-Ti) oxide nanocomposites using an atmospheric soft plasma jet, in this study mixtures of Zn and Ti precursors such as zinc nitrate and titanium butoxide were first prepared with different molar ratios; the mixed precursors then stirred at 700 rpm for two hours with atmospheric plasma, while maintaining a temperature of 25 °C. All the synthesized Zn-Ti oxide nanocomposites were post-heat-treated at 600 °C for six hours in an electrical furnace. The morphology, particle shape and size, crystal structure, oxidation state, and composition ratio were analyzed using FE-SEM, XRD, SEM-EDS, and Raman spectroscopy. BET was measured to calculate the specific surface area of the Zn-Ti oxide nanocomposites. Photocatalytic activity tests were performed for an application study, with 10 mL of 10 ppm methylene blue dye. UV-visible spectroscopy was performed on five different samples in order to analyze the changes of photocatalytic reactions. When the composition ratio of Zn/Ti was 2/1, maximum photocatalytic efficiency was obtained. We also carried out a theoretical kinetic study.

Structural evolution of in situ polymerized poly(L-lactic acid) nanocomposite for smart textile application

This present study demonstrated the preparation of a highly crystalline anatase (ana) form of titanium oxide (TiO2) doped silk nanocrystal (SNC) nanohybrid (ana-TCS) of diameter (7.5 ± 1.4 nm) by the sol–gel method using titanium (IV) butoxide as the hydrolysis material. This prepared nanohybrid with surface hydroxyl groups acted as a co-initiator for the synthesis of poly(L-lactic acid) (PLLA)-g-ana-TSC nanocomposite with grafted PLLA chains via the in situ polymerization technique, using tin-octoate as a catalyst. The fabricated nanocomposite had a high number average molecular weight of 83 kDa with good processibility. This prepared nanocomposite was hydrophobic in nature, with a contact angle of 105°, which was further enhanced to 122 ± 1° when processed via electrospinning technique into a non-woven fabric. The prepared nanocomposite could degrade up to 43% methylene blue dye in 15 days. This nanocomposite showed no significant molecular weight reduction after 1 h of aqeous treatment, which could be attributed to its hydrophobic nature, inhibiting its degradation. However, 50% degradation was observed for the nanocomoposite whereas, PLLA demonstrated 25% degradation in 15 days, after its end-of-life. Thus, this study revealed that the in situ synthesized PLA-ana-TCS nanocomposite could be targeted for use as a hydrophobic, self-cleaning, dye-degradable fabric.

Facile conglomeration of guar gum/TiO2/Fe3O4 composite materials for photocatalytic antimicrobial activities

In present communication we report the guar gum based composite materials, prepared by incorporating TiO2 and Fe3O4 by sol-gel method. The composites were synthesized by hydrolysis and dehydroxylation polymerization of a Titanium (IV) butoxide and mixed oxides of iron (Fe3O4) by the sol-gel method within the guar gum matrix using hydrochloric acid as an acid catalyst. The synthesized materials were calcined in an electrical muffle furnace at 200 °C, 400 °C and 600 °C, and characterized by FTIR, XRD and TGA. Thermal properties of the composites were improved as evidenced from the Thermo Gravimetric Analysis (TGA) data. A strong photocatalytic antimicrobial activity of about 90% was exhibited by composite material calcined at 600 °C against gram-positive (Staphylococcus aureus) bacteria, and therefore, the material could be considered as an important raw material for developing an active food packaging.

Titanium-based metal-organic framework MIL-125(Ti) for the highly selective isolation and purification of immunoglobulin G from human serum.

Titanium-based metal-organic framework MIL-125(Ti) was synthesized by the hydrothermal method of terephthalic acid and tetra butyl titanate in N-N,dimethylformamide, and methanol. MIL-125(Ti) was characterized by Fourier-transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, nitrogen adsorption-desorption, energy-dispersive X-ray spectroscopy, zeta potential, scanning electron microscope, and transmission electron microscopy. The results showed MIL-125(Ti) could be used as a potential adsorbent for protein separation and purification due to the high specific surface area, high stability, and strong hydrophobicity. As a result, MIL-125(Ti) had adsorption selectivity for immunoglobulin G, which was due to the hydrogen bond between MIL-125(Ti) and protein. At pH 8.0, the maximum adsorption efficiency of 0.25mg MIL-125(Ti) for 300μL 100μg/mL immunoglobulin G was 98.3%, and its maximum adsorption capacity was 232.56mg/g. The elution efficiency of immunoglobulin G was 92.4% by 0.1% sodium dodecyl sulfate. sodium dodecyl sulfate-polyacrylamide gel electrophoresis result demonstrated the successful isolation of highly purified immunoglobulin G from the human serum. Therefore, a new method of separation and purification of immunoglobulin G in human serum using titanium-based metal-organic framework MIL-125(Ti) as a solid-phase adsorbent was established, which broadened the application scope of metal-organic frameworks.

Hydrothermal synthesis of BaTiO3 perovskite for H2O2 sensing

In the present study, we reported the fabrication of barium titanate (BaTiO3) nanoparticles using barium nitrate, and titanium (IV) butoxide as Ba and Ti precursors via hydrothermal approach. Further, glassy carbon electrode was modified with BaTiO3 nanoparticles to develop the hydrogen peroxide (H2O2) sensor. Linear-sweep voltammetry (LSV), and chronoamperometry were adopted as electrochemical sensing techniques towards the determination of H2O2. The BaTiO3/GCE demonstrated decent sensitivity of 0.41 µA/µMcm2 and limit of detection (LoD) of 0.89 µM using LSV method whereas sensitivity of 5.49 µA/µMcm2 and LoD of 0.09 µM were obtained using chronoamperometry.

Nanometer TiO2 Film-Based Solar Thin Film Manufacturing Technology and Performance Research

TiO2 sols are usually prepared by sol-gel process using butyl titanate as a precursor, and TiO2 thin films are loaded on ceramic substrates by impregnation lifting method. In this work, the effects of precursor concentration and heat treatment on the properties of TiO2 thin films are investigated to achieve better performance. In addition, the crystal structure of TiO2 is examined by XRD characterization. Experimental results show that the TiO2 films calcined at 500°C are anatase-type structure; the hydrophilic property of the films changes less with the increase of precursor concentration. Moreover, the photodegradation property is improved gradually. The adhesion of the films improved after calcination for each layer of TiO2 films loaded on the ceramic sheet.

PH effect upon sol–gel processing of titanium butoxide and lithium acetate precursors on the characteristics of Li4Ti5O12 as an anode for lithium-ion batteries

pH effect upon sol–gel processing of titanium butoxide and lithium acetate precursors on the characteristics of Li4Ti5O12 as an anode for lithium-ion batteries

Multifunctional Catecholate-Modified 3D TiO2 Nanostructures for Highly Sensitive Photoelectrochemical IL-6 Immunosensors

Protein immunosensors are valuable analytical tools that allow for the detection of proteins with high sensitivity and specificity based on affinity-based interaction between antigen/antibody pairs.1 These devices are increasingly important in clinical settings due to their roles in detecting inflammatory processes, autoimmune disorders, cardiovascular disorders and cancers.1,2 Interleukin-6 (IL-6) is a protein biomarker that plays key roles in immunomodulation, hematopoiesis and inflammatory processes in the human body.3 Elevated levels of IL-6 can be used as evidence for diagnosis of various cancers and autoimmune disorders and even show the progression of COVID-19.3,4 In this work, we developed multifunctional three dimensional (3D) TiO2 nanostructured photoelectrodes as a sensing platform which combine photoelectrochemical (PEC) transduction with a signal-off direct immunoassay to detect IL-6. Surface modification with catecholate ligands was used to modify the properties of TiO2 nanostructures in a three-pronged approach of nanomorphology tuning, photocurrent signal enhancement, and facilitating bioconjugation.3D TiO2 nanostructures were synthesized via acid-hydrothermal process using titanium (IV) butoxide as a precursor. During the synthesis process 3,4-dihydroxybenzaldehyde (DHBA) was added in-situ into the reaction vessel. DHBA is part of the catecholate family of organic ligands which adsorb readily onto TiO2 surfaces. During the synthesis process, DHBA acted as a surfactant with preferential binding affinity for specific crystal facets of TiO2. The addition of DHBA resulted in anisotropic TiO2 crystal growth during synthesis, leading to globular nanorod cluster morphologies with high surface area-to-volume ratios. The 3D TiO2 nanostructures were further modified with extra DHBA after their synthesis. The 3D morphology combined with the extra DHBA resulted in higher UV/visible light absorption and photocurrent density measurements. The synthesized 3D TiO2 nanostructures were used to fabricate photoelectrodes for PEC signal-off immunoassay.The signal-off PEC IL-6 direct immunoassay was constructed by immobilizing a probe layer of anti-IL-6 on the surface 3D TiO2 photoelectrodes. When solutions containing target IL-6 encounter the photoelectrode, IL-6 is immobilized onto the photoelectrode surface through antibody/antigen complexation. Il-6 immobilization on the photoelectrode results in photocurrent signal decrease due to steric hinderance and this signal decrease can be directly correlated to the target concentration. The 3D nanostructure morphology contributed to increased sensitivity for the immunosensor as the higher electroactive surface area can accommodate a higher probe immobilization efficiency. Higher photocurrent generation also resulted in improved limit of detection (LOD) and dynamic range for the sensor. Functionalization by DHBA not only improves photocurrent generation, but also creates an avenue for biofunctionalization through Schiff-base linking between -COH groups of DHBA and -NH2 groups of anti-IL-6. The resultant immunosensor demonstrated excellent performance with an LOD of 3.6 pg mL-1 in plasma and 1.6 pg mL-1 in buffer solution, while having a log-linear dynamic range of 2-2000 pg mL-1. The 3D TiO2 photoelectrodes also demonstrate excellent short-term and long-term stability with little degradation after repeated use.It is evident from our investigations that combining PEC transduction mechanisms with direct signal-off immunoassays can result in high performance biosensors. In particular, the surface modification of 3D TiO2 nanostructure scaffolds with DHBA facilitates the fabrication of materials that are highly nanoporous and generate high photocurrent, resulting in biosensors with large dynamic ranges and low LOD.(1) Zhao, W. W.; Xu, J. J.; Chen, H. Y. Photoelectrochemical Immunoassays. Anal. Chem. 2018, 90 (1), 615–627. https://doi.org/10.1021/acs.analchem.7b04672.(2) Chikkaveeraiah, B. V.; Bhirde, A. A.; Morgan, N. Y.; Eden, H. S.; Chen, X. Electrochemical Immunosensors for Detection of Cancer Protein Biomarkers. ACS Nano 2012, 6 (8), 6546–6561. https://doi.org/10.1021/nn3023969.(3) Khan, M. A.; Mujahid, M. Recent Advances in Electrochemical and Optical Biosensors Designed for Detection of Interleukin 6. Sensors (Switzerland). MDPI AG February 1, 2020. https://doi.org/10.3390/s20030646.(4) Rubin, E. J.; Longo, D. L.; Baden, L. R. Interleukin-6 Receptor Inhibition in Covid-19 — Cooling the Inflammatory Soup. N. Engl. J. Med. 2021, 384 (16), 1564–1565. https://doi.org/10.1056/nejme2103108.

The Influence of the Precursor's Nature and Drying Conditions on the Structure, Morphology, and Thermal Properties of TiO2 Aerogels.

A cost-effective solution for the synthesis of high-porosity TiO2 aerogels, which can be used as a mesoporous perovskite network charge-carrier material during the manufacture of solar cells, is described. The effects of the synthesis parameters (precursor (titanium (IV) isopropoxide (TIP) and tetrabutyl orthotitanate (TBOT)), additional solvent exchange (n-hexane (nH), cyclohexane (CH), and diethyl ether (DE)), subcritical drying (800 mbar vacuum, 70 °C, 8 h), aging, and calcination on the aerogel’s structure have been investigated. Methods of XRD, FT-IR, BET, Raman, STA, SEM, UV–vis, and thermal conductivity measurements were applied to find out the relation between the synthesis conditions and the properties of the synthesized aerogels. Amorphous aerogels are polydispersed systems with the highest probability of pore diameter from 0.5 to 15 nm. An nH-exchanged, aged aerogel synthesized from the precursor TIP shows the highest diameter of pores. After calcination, the aerogels tend to crystallize into an anatase phase and the size of the crystallites depends on the precursor’s nature. Calcination leads to a significant increase in both the apparent and true density of the aerogels, and it also results in an increase in porosity and thermal conductivity.

Biosynthesis of Ag and TiO2 nanoparticles and the evaluation of their antibacterial activities

• Ag and TiO 2 nanoparticles were synthesized using Pseudomonas aeruginosa micro-organism. • The crystalline sizes of the nanoparticles obtained using Image J and Origin software are 7.27 and 6.83 nm for Ag and TiO 2 NPs respectively. • The antibacterial studies showed great inhibition majorly against the Bacillus spp and the TiO 2 NPs was higher in activity more than the AgNPs. • The nanoparticles obtained in this work are more potent than some orthodox antibiotics eg (ciprofloxacin). In this study, Pseudomonas aeruginosa was used for the synthesis of silver and titanium oxide nanoparticles (Ag and TiO 2 NPs). The nanoparticles were prepared by mixing the supernatant solution of the cultured organism and the solution of silver nitrate and titanium tetrabutoxide. UV–Vis spectroscopic analysis gave absorption peak at wavelength of 414 nm and 390 nm for Ag and TiO 2 NPs respectively. The FTIR spectra gave absorption bands attributed to N H stretch of the peptide linkages, O H stretch of carboxylic acid, amide bend, and C O stretch which may have emanated from the micro-organism. The powdered X-ray diffraction (PXRD) studies revealed the crystalline nature of AgNPs and TiO 2 NPs while microscopic studies showed spherical and dispersed morphologies with average particle size of 7.27 nm and 6.83 nm for Ag and TiO 2 NPs respectively. Antibacterial analysis of the synthesized nanoparticles showed broad spectrum inhibition against disease causing microorganisms with TiO 2 NPs exhibiting excellent results more than AgNPs and the control drugs.

Structural and optical characterization of electrospun TiO2 nanofibers using titanium tetrabutoxide and titanium isopropoxide as precursors for photocatalytic applications

The structural and optical characterization of TiO2 nanofibers (TiO2-NF’s) synthesised from two different chemical precursors, titanium tetrabutoxide (TNBT) and titanium isopropoxide (TTIP), obtained by electrospinning technique with controlled morphology and crystalline phase, is presented. Varying the distance between the needle tip and the collector called "air gap", it was possible to control the diameter and the formation of the fibers within the nanometric scale. The crystalline phase (CP) of the TiO2-NFs was controlled through thermal treatment (TT) at 450 °C for 3 h, anatase phase. The chemical composition of the annealed electrospun TiO2-NF was estimated by EDS, finding there is an excess of titanium that causes oxygen vacancies, which stimulate the CP transformation, from amorphous to anatase. By means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) was possible to corroborate the formation of TiO2-NFs with a smooth morphology and well-defined shape. FTIR spectroscopy and Raman scattering results of electrospun TiO2-NFs demonstrated changes in structural and optical properties caused by TT. By Raman scattering was found that the annealed TiO2-NFs showed the anatase CP, which was corroborated by X-ray diffraction. At first sight, the surface morphology of the electrospun fibers was not affected by the choice of precursor; however, on closer review, the fibers prepared with the TTIP precursor showed a smaller crystal size of 8.51 nm and band gap energy of 3.38 eV, while the samples prepared with TNBT showed a smaller bandgap energy of 3.06 eV and a nanocrystal size of 10.98 nm. With both precursors at a working distance of 15 cm, homogeneous fibers are obtained, with a smaller diameter without the presence of morphological defects, called beds, and a better size distribution.

Microwave-Assisted Solvothermal Synthesis of Mo-Doped TiO2 with Exceptional Textural Properties and Superior Adsorption Kinetics.

Assigned to their outstanding physicochemical properties, TiO2-based materials have been studied in various applications. Herein, TiO2 doped with different Mo contents (Mo-TiO2) was synthesized via a microwave-assisted solvothermal approach. This was achieved using titanium (IV) butoxide and molybdenum (III) chloride as a precursor and dodecylamine as a surface directing agent. The uniform effective heating delivered by microwave heating reduced the reaction time to less than 30 min, representing several orders of magnitude lower than conventional heating methods. The average particle size ranged between 9.7 and 27.5 nm and it decreased with increasing the Mo content. Furthermore, Mo-TiO2 revealed mesoporous architectures with a high surface area ranging between 170 and 260 m2 g−1, which is superior compared to previously reported Mo-doped TiO2. The performance of Mo-TiO2 was evaluated towards the adsorption of Rhodamine B (RhB). In contrast to TiO2, which revealed negligible adsorption for RhB, Mo-doped samples depicted rapid adsorption for RhB, with a rate that increased with the increase in Mo content. Additionally, Mo-TiO2 expressed enhanced adsorption kinetics for RhB compared to state-of-the-art adsorbents. The introduced synthesis procedure holds a grand promise for the versatile synthesis of metal-doped TiO2 nanostructures with outstanding physicochemical properties.

A Novel TiO2–TiC–TiC0.3N0.7–C–SiCN Multiphase Ceramic Nanocomposite from Preceramic Polymer Pyrolysis

The current investigation describes the synthesis of SiTiCNO ceramics derived from the mixture of a preceramic polymer (polyvinylsilazane) and tetrabutyl orthotitanate precursors by crosslinking at 300 °C and pyrolysis in the temperature range of 900–1400 °C in flowing nitrogen atmosphere. Crosslinked precursor was studied by thermogravimetry to estimate ceramization temperature as well as ceramic yield. Further, the evolution of phase and nanostructure with temperature in the composite SiTiCNO ceramics was analyzed by the help of different characterization techniques, such as XRD, Raman, and electron microscopy. The Ti-doped SiCN ceramic system appeared as single-phase SiTiCNO amorphous up to 1100 °C. The phase separation of SiTiCNO ceramics started at 1200 °C and exhibited TiO2 nanocrystals distributed in the amorphous SiCN matrix. Ti-doping was found to accelerate the separation of the free carbon phase from the SiCN matrix, and the said carbon had better graphitic order in the Ti-doped SiCN samples as compared to the undoped SiCN of equivalent thermal history. At 1400 °C, high temperature stable phases such as TiC and TiC0.3N0.7 were formed along with predominant rutile-TiO2 phase within the Si–Ti–O–C–N composite. A uniform distribution of these nanocrystals in the SiCN matrix at 1400 °C was observed by high resolution transmission electron microscopy. The current work exhibits the formation of a unique multiphase composite with the co-existence of nanocrystalline phases uniformly distributed within a polymer derived ceramic matrix.

Preparation, Characterization of ZnTiO3/ZnO Composite Materials and Their Photocatalytic Performance.

With zinc acetate and butyl titanate as raw materials, pure ZnO and ZnTiO3/ZnO composite photocatalysts were synthesized by a sol–gel method and calcined at 550 °C. The crystal structure, morphology, surface area, optical property, and element valence states of samples were characterized and the photocatalytic activity of the prepared photocatalysts were assessed by the degradation of rhodamine B. Results show that the crystal structure of ZnO is a hexagonal wurtzite phase with a band gap of 3.20 eV. When the Zn/Ti molar ratio reaches 0.2, ZnTiO3 phase appears and ZnTiO3/ZnO composite forms, which advances the transfer of photogenerated charges. ZnTiO3/ZnO (Ti/Zn = 0.2) exhibits the highest photocatalytic activity, and the degradation degree of RhB reaches 99% after 60 min, which is higher than that of pure ZnO (90%). An exorbitant Ti/Zn molar ratio will reduce the crystallinity and form more amorphous components, which is not conducive to photocatalytic performance. Therefore, when the Ti/Zn molar ratio exceeds 0.2, the photocatalytic activities of ZnTiO3/ZnO composites decrease.

Preparation and characterization of palladium-doped titanium dioxide for solar cell applications

The syntheses of TiO2 and Pd/TiO2 nanoparticles were carried by hydrolysis of alkoxide precursors using the reverse micelles method using titanium tetrabutoxide and palladium acetylacetonate as precursor metals. The method was modified by precipitation with the addition of n-butanol and then washed with an ethanol/water solution at a ratio of 1:1. Morphological characterization was performed by scanning electron microscopy and structural by X-ray diffraction and spectroscopy of Raman scattering. Electrical characterization was performed by impedance spectroscopy and the optical energy gap was determined from transmittance measurements Tauc plot fittings. The material was characterized by a suspension of spherical nanoparticles on the order of 100 nm confirmed by Scanning electron microscopy analysis. They also presented good ionic conductivity as indicated by impedance spectroscopy. Raman spectroscopy showed a systematic frequency shift to the left together with peak broadening as the amount of palladium incorporated onto TiO2 increases, which is characteristic of mesoscopic grains. X-ray diffractograms were carried with washed and dried powder samples and showed a mixture of anatase and brookite phases, with anatase as the predominant one.