Deposition Of TiO2 Nanoparticles Research Articles

Functionalization of cotton fabrics with corona/air RF plasma and colloidal TiO2 nanoparticles

This study discusses the possibility of using a corona discharge at atmospheric pressure and air RF plasma at low pressure for the cotton fibre activation prior to deposition of colloidal TiO2 nanoparticles in order to enhance antibacterial, UV protective and self-cleaning properties. X-ray photoelectron spectroscopy (XPS) analysis confirmed the presence of TiO2 nanoparticles on the surface of cotton fibres. XPS elemental mapping indicated that TiO2 nanoparticles were more evenly distributed across the surface of untreated and corona pre-treated cotton fabrics in comparison with RF plasma pre-treated fabric. Atomic absorption spectroscopy measurements revealed that the equivalent total content of TiO2 in the cotton fabrics pre-treated by corona and RF plasma was 31% higher than in the fabric that did not undergo any treatment prior to loading of TiO2 nanoparticles. In order to achieve maximum bacteria (Gram-negative bacteria Escherichia coli) reduction, untreated cotton fabric had to be loaded with colloidal TiO2 nanoparticles twice, but only once following corona or RF plasma pre-treatment. Deposition of TiO2 nanoparticles onto cotton fabrics provided maximum UV protective rating of 50+. Extraordinary photocatalytic activity of TiO2 nanoparticles deposited onto cotton fabrics was proved by self-cleaning of blueberry juice stains and photodegradation of methylene blue in aqueous solution under UV illumination.

Mesoporous TiO2 Films Fabricated Using Atmospheric Pressure Dielectric Barrier Discharge Jet

TiO2 nanoparticles were synthesized by a facile method of dielectric barrier discharge jet (DBD jet) for the dye-sensitized solar cell (DSSC) and other potential applications. DBD jet is utilized as a method for deposition of TiO2 nanoparticles with a 9 μm/min growth rate which is more than ×25 faster than reported previously. Their performance was compared with cells fabricated using commercial TiO2 nanoparticles (P25). The crystallinity and chemical bonding states of samples were characterized by XRD and XPS. Photoanodes fabricated by the DBD jet method resulted in approximately 50% higher photoconversion efficiency than ones prepared from P25 nanoparticles.

Fabrication of 3D Nano-structured ITO Films by RF Magnetron Sputtering

In this research, RF magnetron sputtering was employed to grow 3D nano-structured ITO thin films using the barrier-layer side of an anodic aluminum oxide (AAO) as the template. The template was prepared by immersing this side of an AAO film into a 30 wt% phosphoric acid solution to modify the surface of the barrier layer in such a manner that a contrasting surface was obtained. The resistivity and crystallinity of the deposited ITO thin film were characterized by I-V curves and X-ray diffraction (XRD). As illustrated in the I-V curve measurements, the resistivity of the ITO film after annealing was 8.25x10-3 Ω -cm. The XRD analysis results of the annealed ITO film clearly showed the characteristic (222) and (400) peaks which characterize the crystallinity. A nano-hemispheric TiO2/ITO array electrode for dye-sensitized solar cells (DSSC) was further fabricated through electrophoretic deposition of TiO2 nanoparticles on the nano-hemispheric ITO array.

Laser annealed composite titanium dioxide electrodes for dye-sensitized solar cells on glass and plastics

We report a rapid and low temperature process for fabricating composite TiO2 electrodes for dye-sensitized solar cells on glass and plastics by in tandem spray deposition and laser annealing. A homogenized KrF excimer laser beam (248 nm) was used to layer-by-layer anneal spray deposited TiO2 nanoparticles. The produced TiO2 film is crack free and contains small particles (30 nm) mixed with different fractions of larger particles (100–200 nm) controlled by the applied laser fluence. Laser annealed double-layered structure is demonstrated for both doctor-blade deposited and spray-deposited electrodes and performance enhancement can be observed. The highest demonstrated all-laser-annealed cells utilizing ruthenium dye and liquid electrolyte showed power conversion efficiency of ∼3.8% under simulated illumination of 100 mW/cm2.

Deposition of TiO2 nanoparticles in surfactant-containing aqueous suspension by a pulsed DC charging-mode electrophoresis

A pulse electrophoresis method was designed for depositing TiO2 nanoparticles on a metal substrate inside an aqueous suspension. The suspension was prepared by mixing the commercially available nanometer-sized TiO2 powders (P25, Degussa) with an organic surfactant in water. A suspension with relatively high concentration (30 wt%) is stable for a few months; therefore it was not necessary to place an additional mixing during the deposition process. In the range of 2.5 to 40 Hz, the pulse direct current (PDC) charging type electrophoretic with a maximum applied voltage of 54 V (50% duty cycle) could narrow the particle size distribution or dispersity of TiO2 particles depositing on the surface of a stainless steel electrode. The morphology of the TiO2 nanoparticles layer deposited by PDC charging-mode was finer than those was deposited by a direct current (DC) charging mode.

Fabrication of High Conductivity TiO2/Ag Fibrous Electrode by the Electrophoretic Deposition Method

TiO2 deposited on a membrane of Ag fibers was prepared as a photoelectrochemical cell electrode. Ag fibers were made by reduction of Ag complexes on cellulose fibers, followed by burning out the template. TiO2 photocatalyst layers were grown on the fibers by electrophoretic deposition of TiO2 nanoparticles. Ag fibers could be uniformly deposited. Photocatalytic tests by dye decomposition and electrochemical impedance spectroscopy (EIS) under UV illumination demonstrate that Ag fibers act as a good substrate that provides both high surface area and good separation of photogenerated electron−hole pairs and causes the enhancement of photocatalytic activity in comparison with a thin film of TiO2.

Combined TiO2/SiO2 mesoporous photocatalysts with location and phase controllable TiO2 nanoparticles

Combined TiO2/SiO2 mesoporous materials were prepared by deposition of TiO2 nanoparticles synthesised via the acid-catalysed sol–gel method. In the first synthesis step a titania solution is prepared, by dissolving titaniumtetraisopropoxide in nitric acid. The influences of the initial titaniumtetraisopropoxide concentration and the temperature of dissolving on the final structural properties were investigated. In the second step of the synthesis, the titania nanoparticles were deposited on a silica support. Here, the influence of the temperature during deposition was studied. The depositions were carried out on two different mesoporous silica supports, SBA-15 and MCF, leading to substantial differences in the catalytic and structural properties. The samples were analysed with N2-sorption, X-ray diffraction (XRD), electron probe microanalysis (EPMA) and transmission electron microscopy (TEM) to obtain structural information, determining the amount of titania, the crystal phase and the location of the titania particles on the mesoporous material (inside or outside the mesoporous channels). The structural differences of the support strongly determine the location of the nanoparticles and the subsequent photocatalytic activity towards the degradation of rhodamine 6G in aqueous solution under UV irradiation.

Flexible Nano-Photo-Electrochromic Film

A flexible nano-photo-electrochromic poly(ethylene terephthalate) (PET)−TiO2−PO4−methylene blue (MB) based film was obtained by the deposition of TiO2 nanoparticles on a PET conductive substrate. A further covalent chemical bond of MB molecules on the TiO2 film by means of phosphate groups ensures the photo-electrochromic properties of this device. Indeed, MB molecules can change color both owing to the irradiation with red light, in the presence of electron donor molecules, and owing to the oxidation reaction with an oxidizing agent. Because the oxidation reaction of MB molecules occurs at the same electrode where the molecules are anchored, the film shows a very fast coloration time (600 ms). The thermal stability of the film and the anchoring of MB molecules on TiO2 nanoparticles were investigated by the differential scanning calorimetry technique. The morphologies of the surface and cross section of the TiO2 layer were studied by a scanning electron microscope. Moreover, the device was characterized i...