TiO2 Sol Concentration Research Articles

An Investigation into Electrodeposited Co−Ni−TiO2 Films with Improved Mechanical and Corrosion Properties

This investigation proposes the use of sol-enhanced electrodeposition to create a range of Co−Ni−TiO2 films. The addition of TiO2 sol controls the nucleation process and the properties of the composite films by generating TiO2 nanoparticles in situ in the electrodeposition process. The transmission electron microscopy (TEM) and zeta potential analyses revealed a relatively homogenous distribution with particle size in the range below 100 nm for the TiO2 nanoparticles produced. Microstructure, phase composition, hardness, friction, and corrosion resistance of Co−Ni−TiO2 films were thoroughly investigated in relation to TiO2 sol concentration. The results show that the addition of a limited content of TiO2 sol upgraded Co−Ni films by producing a Co−Ni−TiO2 film with a high dispersion of TiO2 nanoparticles. On the other hand, too much TiO2 sol could cause agglomeration and hinder the metal deposition process, resulting in surface pores and the deterioration of film performance.

Preparation and Properties of Sn-TiO2 nanocomposite coatings

Sn-TiO2 nanocomposite coatings were prepared by sol-gel enhanced electrodeposition technique and the effect of c concentration on the performance of the composite coatings was investigated by adding different volumes of TiO2 sol to the electrolyte. The microscopic morphology and corrosion resistance of the coatings were characterized by XRD tests, SEM tests, hardness tests and a series of electrochemical tests. From the test results, it was found that the coating had the highest hardness value and the best corrosion resistance when the TiO2 sol was added at 15 mL/L; however, when the TiO2 sol concentration was too large, the corrosion resistance and hardness value of the Sn-TiO2 composite coating decreased significantly due to the destruction of the crystal structure and coating structure by the agglomerated TiO2 nanoparticles in the coating.

Formation of TiO<sub>2</sub> Coating by the Sol-Gel on Carbon Fibers

Solutions with various concentrations of TiO2 were obtained and studied. The morphology of the carbon fiber with TiO2 coatings was investigated. The TiO2 concentration significantly effects on viscosity and coatings formed on carbon fibers. The relationship between TiO2 sol concentration and the mass oxide on the surface of carbon fibers was studied.

A novel CuSbS2–TiO2 nanoparticles synergy structure for photocatalysis

In this work, a synergy structure to improve the photocatalytic properties of materials was proposed. CuSbS2 nanoparticles synthesized by microwave irradiation method were dispersed in TiO2 sol to form CuSbS2–TiO2 nanoparticles. The properties of composite materials with different TiO2 sol concentration were investigated by XRD, XPS, etc. The results indicated the as-synthesized CuSbS2 nanoparticles exhibited chalcostibite structure and the TiO2 showed anatase phase. The CuSbS2–TiO2 nanoparticles had high absorbance in the visible light and good photocatalysts for the photodegradation reaction of Rhodamine B (RhB). When TiO2 sol concentration was 0.23 mol/L, the sample possessed a photocatalytic degradation rate of 0.002 min−1 for the degradation of RhB, which was 3 times higher than that by the bare amorphous TiO2 (0.0007 min−1).

The effects of TiO2 sol concentration on single- and multiple-scratch damage in electroplated Ni–B-TiO2 sol composite coating

The electrodeposited sol-enhanced Ni–B–TiO2 composite coatings were elaborated using a novel electroplating process. This coating was assessed in terms of tribological behavior and corrosion resistance. However, the adhesion strength of this coating has not been discussed so far. The aim of this study is to evaluate the adhesion behavior of this coating, considering different TiO2 sol concentration in the plating solution in order to predict its effectiveness and its sustainability when used in mineral crushing process. A progressive load scratch test and multi-pass scratch test were performed on coatings. The morphology of scratched surfaces was analyzed to identify the scratch failure mechanism. The results indicate that the addition of TiO2 sol significantly enhanced the deposit adhesion to the substrate compared to pure Ni–B coating. No spallation failure was observed on the sol-enhanced coatings after progressive load scratch test, contrary to Ni–B coating. Moreover, the multi-pass scratch test demonstrated that the improvement in adhesion strength depends strongly on the quantity of the TiO2 sol added to the plating solution. For the optimal concentration of TiO2 sol (25 ml/L), the sol-enhanced Ni–B–TiO2sol composite coating boasts the best adhesion strength. However, further increase in TiO2 sol concentration results in a deterioration of coating adhesion.

Microstructure and properties of sol-enhanced Co-P-TiO2 nano-composite coatings

Co-P coatings have been widely used as the replacement of hexavalent chromium coatings. In order to improve the properties of Co-P coatings, Co-P-TiO2 nano-composite coatings were prepared using a novel sol-enhanced method. The microstructure, mechanical properties and corrosion resistance of sol-enhanced Co-P-TiO2 nano-composite coatings were systematically investigated. The results show that sol-enhanced Co-P-TiO2 coating with a good dispersion of TiO2 nanoparticles can be obtained by adding an appropriate amount of TiO2 sol to the bath. The microhardness of Co-P-12.5 mL/L TiO2 coating was increased by ∼18% compared to that of Co-P coating. Its wear resistance and corrosion resistance were also significantly improved. The effects of TiO2 sol concentration on the microstructure, mechanical properties and corrosion resistance of Co-P-TiO2 nano-composite coatings were discussed in detail.

Microstructure and properties of TiO2 sol-enhanced black nickel nanocomposite coating

Black nickel coatings are widely used in industries due to their shiny black color and other unique properties. However these coatings are normally soft, which limits their applications. In order to increase the mechanical properties of black nickel coatings, sol-enhanced technology has been applied to the plating process. TiO2 sol-enhanced black nickel nanocomposite coatings were electroplated on nickel-coated brass. A systematic study on the microstructure and properties of the black coatings were conducted. The effects of TiO2 concentration (TiO2 sol concentration in 0–20 mL/L) on the surface morphology, nanohardness and wear resistance have been studied. The results indicated that the nanohardness of the sol-enhanced black nickel coating was increased by [Formula: see text]20%. The mechanisms of improvement and surface morphology variation were also discussed.

Microstructural and photocatalytic characterization of cement-paste sol-gel synthesized titanium dioxide

A route for the in paste synthesis of TiO2 loaded cement is described. TiO2 sols are blended with fresh cement paste as an alternative process to add photocatalytic functionality to cement. The modification of cement paste structure after the addition of TiO2 sols is analyzed by XRD, SEM and TGA. As a particular microstructural feature, TiO2 containing calcium silicate hydrate (C-H-S) particles are identified as networking centers of a C-S-H gel fiber matrix. The increase of the TiO2 sol concentration induces a decrease of pore size and an increase in the specific surface area in the cement composites. The photocatalytic activity of the TiO2/cement system is evaluated from the degradation of Methylene Blue (MB) under UVirradiation, monitored through the absorbance at 665 nm. The results show that, although TiO2 phases reveal no long range order structure, the cement paste exothermal treatment in presence of hydrate products and alkaline conditions leads to a photocatalytic composite. Such new cement matrix may be twofold advantageous since it additionally promotes the formation of C-S-H gel, main determinant of cement mechanical properties.

Preparation and properties of polyamide/titania composite nanofiltration membrane by interfacial polymerization

The TiO2 sol was added in the polysulfone (PSF) casting membrane solution to prepare polysulfone/titania hybrid membrane in this work. Then the polypiperazine–amide composite nanofiltration (NF) membranes were prepared on PSF/TiO2 hybrid membranes by interfacial polymerization. Piperazine and trimesoyl chloride were used as monomers in aqueous phase and organic phase, respectively. Different preparation conditions affecting the separation performances of NF membrane were discussed, including TiO2 sol concentration, piperazine concentration, trimesoyl chloride concentration, and reaction time. The chemical structure characterizations of polyamide composite membrane were tested by attenuated total reflectance infrared (ATR-IR). The surface images and cross sections were observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The addition of TiO2 sol changed the salt rejection slightly, but the water flux was three times than that of the polyamide membrane on the PSF support membrane. The polyamide NF membrane prepared under the optimum condition exhibited Na2SO4 rejection of 96.94% and water flux of 12.84Lm−2h−1. According to the intercepting experiments of polyethylene glycols, the molecular weight cut-off (MWCO) of the resulting membrane was under 600Da.

Fabrication of ZnO/SrTiO3 nanoarrays and its photoelectrochemical performances

The ZnO/SrTiO3 nanomaterials were fabricated by a chemical conversion hydrothermal method in order to utilize the high electron transfer rate of one-dimensional ZnO nanorods and photocatalytic activity of SrTiO3. The technological parameters, such as TiO2 sol concentration, TiO2 sol dipping cycle, Sr(NO3)2 concentration and reaction temperature, were investigated in the synthetic process and the reaction mechanism of the ZnO/SrTiO3 nanomaterials was proposed. A photocurrent density of 7.53 mA/cm2 was obtained for the as-prepared ZnO/SrTiO3 photocatalyst, attributed to its improved absorption spectrum and appropriate nanostructure, which indicates a potential application in photoelectrochemical water splitting.

Preparation of SiO<sub>2</sub> Aerogel Supported Nano-TiO<sub>2</sub> Photocatalysts for Removing Rhodamine B in the Waste Water

Using the as-prepared SiO2 aerogels as carriers, SiO2 aerogel supported nano-TiO2 (TiO2/SiO2 aerogel) photocatalysts were prepared by sol-gel and adsorption loading process. The microstructure, morphology and properties of the obtained TiO2/SiO2 aerogel were studied by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and Brunauer-Emmett-Teller (BET) N2 adsorption-desorption analysis. The adsorption/photocatalytic degradation for Rhodamine B of TiO2/SiO2 aerogel composite photocatalysts was investigated. The results indicate that TiO2 sol concentration is the main factor influencing the microstructure and properties of TiO2/SiO2 aerogel composite photocatalysts. With the increasing of TiO2 sol concentration, the amount of loaded TiO2 increased, but the specific surface area, pore volume and pore size gradually decreased. The specific surface area, pore volume and pore diameter of TiO2/SiO2 aerogel photocatalysts after annealed at 550oC are 444.76～750.34 m2/g, 0.08～0.70 m3/g and 2.46～4.58nm, respectively. The TiO2/SiO2 aerogel prepared with 0.75 mol/L TiO2 sol concentration has best adsorption/photocatalytic degradation for Rhdamine B.

Cytotoxicity Property of Nano-TiO2Sol and Nano-TiO2Powder

A homogeneous and transparent titania (TiO2) sol with nanosized anatase TiO2particles was prepared by hydrothermal synthesis method. The transmission electron microscope and X-ray diffraction were used to characterize the structure and morphology of particulates in the TiO2sol and purchased TiO2powder. The results show that the homogeneous anatase crystalline phase was formed and the size of the spindle-like particle in sol was about 20 nm in width and 150 nm in average length, and the particulates of the purchased powder were globular-like about 50 nm in diameter. In addition, a consistent set of in vitro experimental protocols was used to study the effects of nano-TiO2sol as prepared and nano-TiO2powder on mouse peritoneal macrophage. The cytotoxicity tests in vitro indicate that, with the increasing of TiO2sol concentration contaminated with the cells, the relative proliferation rate of macrophage cells was improved slightly after the cells contaminated for 24 h, but it reduced rapidly after contaminated for 48 h. The purchased nano-TiO2powder inhibited the growth of the cells obviously as cultivating with macrophage both for 24 h and 48 h.

Multiwall Carbon Nanotube and TiO<SUB>2</SUB> Sol Assembly

Carbon nanotube and TiO2 assemblies (CNT/TiO2) have the great promise of combining the advantages of CNTs and TiO2 as photocatalytic and energy conversion materials. In this study, nanoscale TiO2 sol was assembled onto multiwall carbon nanotubes (MWCNTs). The CNT/TiO2 sol assemblies were characterized by transmission electron microscopy, energy dispersive spectroscopy, and Fourier transform infrared spectroscopy. The study shows that the acidic functional group concentration on CNT surfaces increases with surface modification temperature, up to 1.179 mmol/g. Higher concentration of acidic functional group greatly improves the amount of TiO2 sol assembled onto MWCNTs. Higher TiO2 sol concentration also improves the amount of TiO2 sol assembled onto MWCNT surfaces. The assembly mechanism is mainly by chemical reaction between the -COOH groups of MWCNTs and the -OH groups of TiO2 sol by esterification.

Fabrication of Ordered TiO2 Porous Thin Films by Sol-Dipping PS Template Method

Monolayer polystyrene spheres (∼400 nm) array templates were assembled orderly on clean glass substrates by dip-drawing method from emulsion of PS and porous TiO2 thin films were prepared by using sol-dipping template method to fill TiO2 sol into the interstices among the close-packed PS templates and then annealing to remove the PS templates. The effects of TiO2 precursor sol concentration and dipping time in sol on the porous structure of the thin films were studied. The results showed pore size of the ordered TiO2 porous thin film depended mainly on PS size and partly on TiO2 sol concentration. The shrinkage of pore diameter was about 10% for 0.2 M and 20% for 0.4 M TiO2 sol concentrations. X-ray diffraction (XRD) spectra indicated the porous thin film was anatase structure. The transmittance spectrum showed that optical transmittance of the porous thin film kept above 70% beyond the wavelength of 430 nm. Optical band-gap of the porous TiO2 thin film (fired at 550∘;C) was 3.12 eV.