Study of Nd3+, Pd2+, Pt4+, and Fe3+ dopant effect on photoreactivity of TiO2 nanoparticles

Preparation of Iron-Doped Titania Nanoparticles and Their UV-Blue Light-Shielding Capabilities in Polyurethane

It is well known that ultraviolet (UV) and blue light cause a series of health problems and damages to polymer materials. Therefore, there are increasing demands for UV-blue light-shielding. Herein, a new type of iron-doped titania (Fe-TiO₂) nanoparticle was synthesized. Fe-TiO₂ nanoparticles with small particle size (ca. 10 nm) are composed of anatase and brookite. The iron element is incorporated into the lattice of titania and forms a hematite phase (α-Fe₂O₃). The iron doping imparted full-band UV and blue light absorption to Fe-TiO₂ nanoparticles, and greatly suppressed the photocatalytic activity. The prepared Fe-TiO₂/polyurethane (PU) films exhibited prominent UV-blue light-shielding performance and high transparency, which showed great potential in light-shielding fields.

A review of graphene-TiO2 and graphene-ZnO nanocomposite photocatalysts for wastewater treatment

Technologies for wastewater remediation have been growing ever since the environmental and health concern is realized. Development of nanomaterials has enabled mankind to have different methods to treat the various kinds of inorganic and organic pollutants present in wastewater from many resources. Among the many materials, semiconductor materials have found many environmental applications due to their outstanding photocatalytic activities. TiO₂ and ZnO are more effectively used as photocatalyst or adsorbents in the withdrawal of inorganic as well as organic wastes from the wastewater. On the other hand, graphene is tremendously being investigated for applications in environmental remediation in view of the superior physical, optical, thermal, and electronic properties of graphene nanocomposites. In this work, graphene-TiO₂ and graphene-ZnO nanocomposites have been reviewed for photocatalytic wastewater treatment. The various preparation techniques of these nanocomposites have been discussed. Also, different design strategies for graphene-based photocatalyst have been revealed. These nanocomposites exhibit promising applications in most of the water purification processes which are reviewed in this work. Along with this, the development of these nanocomposites using biomass-derived graphene has also been introduced. PRACTITIONER POINTS: Graphene-TiO₂ and graphene-ZnO nanocomposites are effective for wastewater treatment through photocatalysis. These nanocomposite photocatalysts have been used in the form of membrane as well as antibacterial agents. Synthetic strategies and design considerations of graphene-based photocatalyst play a major role. Biomass-derived graphene-TiO₂ and graphene-ZnO nanocomposites have also found application in wastewater treatment.

Solochrome Dark Blue Azo Dye Removal by Sonophotocatalysis Using Mn2+ Doped ZnS Quantum Dots

This work investigates the degradation of the azo dye solochrome dark blue (SDB) by measurement of the photocatalytic, sonocatalytic and sonophotocatalytic activities, under low ultrasonic frequency (40 kHz) and UV-C (254 nm) light, using Mn-doped ZnS semiconductor quantum dots (Mn2+:ZnS Qds) as catalysts, prepared by a simple chemical precipitation procedure. In order to study the different morphological and optical crystal properties, various characterization techniques were used, such as high resolution transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray analysis, X-ray diffraction, N2 adsorption-desorption at −196 °C and ultraviolet-visible spectroscopy. The average particle size of the semiconductor Qds was in the range of 3–4 nm. The optimal parameters affecting dye degradation, such as the catalyst loading, solution pH, time of irradiation, initial concentration of dye, dopant concentration, ultrasonic power and frequency effect were evaluated. The synthesized catalytic material exhibited a high activity for sonophotocatalytic degradation of SDB (89%), larger than that observed for sonocatalysis (69.7%) or photocatalysis (55.2%) alone, which was due to the improved electron-holes separation, formation of more reactive radicals and enhancement of the active surface area. Qds showed good stability and reusability after five repeated cycles. Finally, the degradation products were identified by liquid chromatography-mass spectrometry (LC-MS).

A Review on the Pathways of the Improved Structural Characteristics and Photocatalytic Performance of Titanium Dioxide (TiO2) Thin Films Fabricated by the Magnetron-Sputtering Technique

Titanium dioxide (TiO2) thin films are used for a broad range of applications such as wastewater treatment, photocatalytic degradation activity, water splitting, antibacterial and also in biomedical applications. There is a wide range of synthesis techniques for the deposition of TiO2 thin films, such as chemical vapor deposition (CVD) and physical vapor deposition (PVD), both of which are well known deposition methods. Layer by layer deposition with good homogeneity, even thickness and good adhesive nature is possible by using the PVD technique, with the products being used for photocatalytic applications. This review studies the effects of magnetron sputtering conditions on TiO2 films. This innovative technique can enhance the photocatalytic activity by increasing the thickness of the film higher than any other methods. The main purpose of this article is to review the effects of DC and RF magnetron sputtering conditions on the preparation of TiO2 thin films for photocatalysis. The characteristics of TiO2 films (i.e., structure, composition, and crystallinity) are affected significantly by the substrate type, the sputtering power, the distance between substrate and target, working pressure, argon/oxygen ratio, deposition time, substrate temperature, dopant types, and finally the annealing treatment. The photocatalytic activity and optical properties, including the degree of crystallinity, band gap (Eg), refractive index (n), transmittance (T), and extinction coefficient (k), of TiO2 films are dependent on the above- mentioned film characteristics. Optimal TiO2 films should have a small particle size, a strong degree of crystallinity, a low band gap, a low contact angle, a high refractive index, transmittance, and extinction coefficient. Finally, metallic and nonmetallic dopants can be added to enhance the photocatalytic activity of TiO2 films by narrowing the band gap.

Assessing the Photocatalytic Degradation of Fluoroquinolone Norfloxacin by Mn:ZnS Quantum Dots: Kinetic Study, Degradation Pathway and Influencing Factors

Norfloxacin (NOFX), a broadly used fluoroquinolone antibiotic, has been a subject of great concern in the past few years due to its undesirable effect on human beings and aquatic ecosystems. In this study, novel Mn doped ZnS (Mn:ZnS) quantum dots (QDs) were prepared through a facile chemical precipitation method and used as photocatalysts for NOFX degradation. Prior to photodegradation experiments, morphological and optical parameters of the QDs were examined through transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray analysis, Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, fluorescence spectroscopy, Brunauer-Emmett-Teller analysis, and differential thermal and thermogravimetric analyses. Mn:ZnS QDs exhibited excellent properties of photodegradation, not only under UV irradiation but also in sunlight, which induced NOFX to photodegrade. The utmost photodegradation efficiency was obtained under optimal conditions (25 mL of NOFX, 15 mg/L, pH 10, 60 min UV irradiation, 60 mgs QDs), adopting first order kinetics. In addition, hydroxyl radicals produced by the conduction band electrons were found to be the primary reason dominating the transformation of NOFX in basic conditions, while holes, oxygen atoms, as well as the doped metal (Mn) enhanced the degradation. The QDs showed excellent reusability and stability in four repeated cycles. Finally, four different pathways were predicted, derived from the identified intermediates, with piperazinyl ring transformation being the primary one. It is expected that the synthesized Mn:ZnS QDs could be utilized as efficient photocatalytic materials for energy conversion and ecological remediation.

Bi0.9Ho0.1FeO3/TiO2 Composite Thin Films: Synthesis and Study of Optical, Electrical and Magnetic Properties

A visible light active Bi_0.9Ho_0.1FeO₃ nanoparticles/TiO₂ composite thin films with different mol.% of Bi_0.9Ho_0.1FeO₃ were successfully prepared via non-aqueous sol-gel method. The incorporation of 5, 10 and 20 mol.% Bi_0.9Ho_0.1FeO₃ nanoparticles in the precursor solution of TiO₂ brings modifications in the functional properties of the composite thin films. XPS analysis indicates that interdiffusion of Fe³⁺, Ho³⁺, Bi³⁺/Ti⁴⁺ ions through the interfaces between Bi_0.9Ho_0.1FeO₃ nanoparticles and TiO₂ matrix reduces the concentration of Ti³⁺ ions. X-ray diffraction analysis affirms that TiO₂ and Bi_0.9Ho_0.1FeO₃ retain anatase and orthorhombic phase respectively in composite films. The composite thin film containing 20 mol.% Bi_0.9Ho_0.1FeO₃ nanoparticles exhibits the most prominent absorption phenomenon in visible region and has significantly reduced indirect band gap of 2.46 eV compared to that of pure TiO₂ (3.4 eV). Hall effect measurements confirm that the resistivity of composite film increases by ∼2.33 orders of magnitude and its carrier concentration decreases by 1.8 orders of magnitude at 5 mol.% Bi_0.9Ho_0.1FeO₃ nanoparticles addition compared to those of pure TiO₂ film. Moreover, the pure film exhibits diamagnetism, whereas the composite films have both large ferromagnetic and small diamagnetic components. The findings in this research justify that the composite film can be a potential candidate for making improved photocatalyst, resistors and spintronic devices.

Photocatalytic efficiency of Fe2O3/TiO2 for the degradation of typical dyes in textile industries: Effects of calcination temperature and UV-assisted thermal synthesis

The inadequate management practices in industrial textile effluents have a considerable negative impact on the environment and human health due to the indiscriminate release of dyes. Photocatalysis is one of the diverse advance oxidation processes (AOPs) and titanium dioxide (TiO₂) is recognized for its high oxidation and reduction power. A composite photocatalyst of Fe₂O₃/TiO₂ is synthesized using different mass ratios of Fe:TiO₂ to improve its photoactivity. The composite photocatalyst is calcined at 300-900 °C. Their photocatalytic activity for the degradation of Congo red (CR) and methyl orange (MO) is investigated by total organic carbon (TOC) analysis. The formation and characterization of the as-prepared composite are studied by scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDS). The effect of calcination temperature on the composite Fe₂O₃/TiO₂ photocatalyst is investigated using Fourier transform infrared spectroscopy (FTIR). The photocatalytic activity and the phase conversion are studied by X-ray diffraction (XRD). The specific surface area of photocatalysts at different calcination temperatures is investigated based on Brunauer-Emmett-Teller (BET) surface area analysis. Results show that at an optimum calcination temperature of 300 °C for the photocatalyst preparation, the specific surface area is maximum and the photocatalyst has the highest photoactivity. Thus, the degradation of organic materials reaches 62.0% for MO and 46.8% for CR in the presence of Fe₂O₃/TiO₂ (0.01 w:w Fe:TiO₂) calcined at 300 °C with the highest specific surface area (98.73 m²/g). The transformation of TiO₂ from anatase to rutile is facilitated by high temperature and high concentration of iron while high crystallization and particle size increase occur. An optimum calcination temperature of 300 °C is found at which the degradation of typical dyes in textile industries is maximum.

Photocatalysis of S-metolachlor in aqueous suspension of magnetic cerium-doped mTiO2 core-shell under simulated solar light

Magnetic cerium-doped mesoporous titanium dioxide was synthesized by combining sol-gel method and calcination using tetrabutanate and ammonium cerium nitrate as precursors and Pluronic P123 as a template coating on iron oxide covered with carbon in ethanol. The magnetic Ce-doped catalyst showed only anatase structure with a slight increase in lattice parameters compared to the undoped catalyst. The Ce L_III-edge X-ray absorption near-edge spectroscopy (XANES) spectra showed Ce³⁺, and the cerium substitution doping into titanium dioxide was proposed. Degradation of S-metolachlor in aqueous magnetic photocatalyst suspension followed (pseudo) first-order kinetics in the presence of 0.5 g L^-1 of γ-Fe₂O₃@C@0.16 mol% Ce-mTiO₂ with a half-life of 55.18 ± 1.63 min. Fifteen degradation products were identified, and their transformation routes of the photocatalytic degradation were then proposed. Complementary toxicity assessment of the treated S-metolachlor solution was undertaken with Environment Canada's algal microplate assay measuring growth inhibition (72-h IC₅₀) in the freshwater chlorophyte Pseudokirchneriella subcapitata. This test method revealed a significant decrease in toxicity (1.7-fold reduction after 180 min of irradiation treatment), thereby confirming that the by-products formed following photocatalysis would be less harmful from an environmental point of view. Photocatalytic degradation of S-metolachlor thus appears to hold promise as a cost-effective treatment technology to diminish the presence of this herbicide in aquatic systems.

Identifying the role of reactive oxygen species (ROSs) in Fusarium solani spores inactivation

The inactivation mechanism of photocatalytic disinfectants on bacteria is well known. In contrast, the potential inactivation of fungal spores by visible-light induced photocatalysis has been recognized, but the inactivation mechanism is poorly understood. We hypothesize that photocatalytically generated reactive oxygen species (ROSs) are directly involved in this mechanism. To test this hypothesis, we identified the roles of ROSs in the inactivation of Fusarium solani spores. As the photocatalysts, we doped TiO₂ with 3 typical dopants, forming Ag/TiO₂, N/TiO₂ and Er³⁺:YAlO₃/TiO₂. The Ag/TiO₂ photocatalysis was dominated by H₂O₂, with the longest lifetime among the investigated ROSs. Ag/TiO₂ photocatalysis yielded almost 100 % inactivation efficiency and preserved the cell-wall shape of the spores, thus minimizing the biomolecule leakage. Er³⁺:YAlO₃/TiO₂ was dominated by h⁺ ROSs, yielding an inactivation efficiency of 91 %; however, the severe leakage released large numbers of molecular bio-products. Severe damage to the cell walls by the h⁺ species was confirmed in micrograph observations. Subsequent to cell wall breakage, the Er³⁺:YAlO₃/TiO₂ nanoparticles entered the spore cells and directly oxidized the intracellular material. The N/TiO₂ photocatalysis, with •O₂⁻ dominated ROSs, delivered intermediate performance. In conclusion, photocatalysts that generate H₂O₂-dominated ROSs are most preferred for spore inactivation.

A mini-review on rare earth metal-doped TiO2 for photocatalytic remediation of wastewater

Titanium dioxide (TiO2) has been considered a useful material for the treatment of wastewater due to its non-toxic character, chemical stability and excellent electrical and optical properties which contribute in its wide range of applications, particularly in environmental remediation technology. However, the wide band gap of TiO2 photocatalyst (anatase phase, 3.20 eV) limits its photocatalytic activity to the ultraviolet region of light. Besides that, the electron-hole pair recombination has been found to reduce the efficiency of the photocatalyst. To overcome these problems, tailoring of TiO2 surface with rare earth metals to improve its surface, optical and photocatalytic properties has been investigated by many researchers. The surface modifications with rare earth metals proved to enhance the efficiency of TiO2 photocatalyts by way of reducing the band gap by shifting the working wavelength to the visible region and inhibiting the anatase-to-rutile phase transformations. This review paper summarises the attempts on modification of TiO2 using rare earth metals describing their effect on the photocatalytic activities of the modified TiO2 photocatalyst.

Rapid and morphology controlled synthesis of anionic S-doped TiO2 photocatalysts for the visible-light-driven photodegradation of organic pollutants

In recent years, growing concerned has been raised to the global problem of the drainage of organic pollutants into water steams.

The reaction mechanism for the SCR process on monomer V5+ sites and the effect of modified Brønsted acidity

The energetics, structures and activity of a monomeric VO₃H/TiO₂(001) catalyst are investigated for the selective catalytic reduction (SCR) reaction by the use of density functional theory (DFT).

Bi-phasic titanium dioxide nanoparticles doped with nitrogen and neodymium for enhanced photocatalysis

Bi-phasic or multi-phasic composite nanoparticles for use in photocatalysis have been produced by a new synthetic approach. Sol-gel methods are used to deposit multiple layers of active material onto soluble substrates. In this work, a layer of rutile (TiO2) was deposited onto sodium chloride pellets followed by an annealing step and a layer of anatase. After dissolving the substrate, bi-phasic nanoparticles containing half anatase and half rutile TiO2; with "Janus-like" characteristics are obtained. Nitrogen and neodymium doping of the materials were observed to enhance the photocatalytic properties both under UV and white light irradiation. The unique advantage of this synthetic method is the ability to systematically dope separate sides of the nanoparticles. Nitrogen doping was found to be most effective on the anatase side of the nanoparticle while neodymium was found to be most effective on the rutile side. Rhodamine B dye was effectively photodegraded by co-doped particles under white light.

Plasmon-enhanced light harvesting: applications in enhanced photocatalysis, photodynamic therapy and photovoltaics

This review article summarizes the recent progress on surface plasmon-enhanced light harvesting and its applications toward enhanced photocatalysis, photodynamic therapy, chemical transformations and photovoltaics.

Plasmon-enhanced light harvesting: applications in enhanced photocatalysis, photodynamic therapy and photovoltaics

This review article summarizes the recent progress on surface plasmon-enhanced light harvesting and its applications toward enhanced photocatalysis, photodynamic therapy, chemical transformations and photovoltaics.

Plasmon-enhanced light harvesting: applications in enhanced photocatalysis, photodynamic therapy and photovoltaics

This review article summarizes the recent progress on surface plasmon-enhanced light harvesting and its applications toward enhanced photocatalysis, photodynamic therapy, chemical transformations and photovoltaics.

3D-nanoflowers of rutile TiO2 as a film grown on conducting and non-conducting glass substrates for in vitro biocompatibility studies with mouse MC3T3 osteoblast and human HS-5 cells

Thin films of 3D-nanoflowers of rutile TiO₂ on conducting (FTO and ITO) and non-conducting (glass) substrates were grown using a surfactant free one-step hydrothermal process.

Atomic-scale control of TiO₆ octahedra through solution chemistry towards giant dielectric response

The structures of many important functional oxides contain networks of metal-oxygen polyhedral units i.e.MO_n. The correlation between the configurations and connectivities of these MO_n to properties is essentially important to be well established to conduct the design, synthesis and application of new MO_n-based functional materials. In this paper, we report on an atomic-scale solution-chemistry approach that for the first time enables TiO₆ octahedral network control starting from metastable brookite TiO₂ through simultaneously tuning pH values and interfering ions (Fe³⁺, Sc³⁺, and Sm³⁺). The relationship between solution chemistry and the resultant configuration/connectivity of TiO₆ octahedra in TiO₂ and lepidocrocite titanate is mapped out. Apart from differing crystalline phases and morphologies, atomic-scale TiO₆ octahedral control also endows numerous defect dipoles for giant dielectric responses. The structural and property evolutions are well interpreted by the associated H⁺/OH⁻ species in solution and/or defect states associated with Fe³⁺ occupation within TiO₆ octahedra. This work therefore provides fundamental new insights into controlling TiO₆ octahedral arrangement essential for atomic-scale structure-property design.

Large-scale synthesis of TiO2 microspheres with hierarchical nanostructure for highly efficient photodriven reduction of CO2 to CH4

In this study, a simple and reproducible synthesis strategy was employed to fabricate TiO2 microspheres with hierarchical nanostructure. The microspheres are macroscopic in the bulk particle size (several hundreds to more than 1000 μm), but they are actually composed of P25 nanoparticles as the building units. Although it is simple in the assembly of P25 nanoparticles, the structure of the as-prepared TiO2 microspheres becomes unique because a hierarchical porosity composed of macropores, larger mesopores (ca. 12.4 nm), and smaller mesopores (ca. 2.3 nm) has been developed. The interconnected macropores and larger mesopores can be utilized as fast paths for mass transport. In addition, this hierarchical nanostructure may also contribute to some extent to the enhanced photocatalytic activity due to increased multilight reflection/scattering. Compared with the state-of-the-art photocatalyst, commercial Degussa P25 TiO2, the as-prepared TiO2 microsphere catalyst has demonstrated significant enhancement in photodriven conversion of CO2 into the end product CH4. Further enhancement in photodriven conversion of CO2 into CH4 can be easily achieved by the incorporation of metals such as Pt. The preliminary experiments with Pt loading reveal that there is still much potential for considerable improvement in TiO2 microsphere based photocatalysts. Most interestingly and significantly, the synthesis strategy is simple and large quantity of TiO2 microspheres (i.e., several hundred grams) can be easily prepared at one time in the lab, which makes large-scale industrial synthesis of TiO2 microspheres feasible and less expensive.

Evaluation of the photocatalytic activity of Ln3+-TiO2 nanomaterial using fluorescence technique for real wastewater treatment

Evaluation the photocatalytic activity of different Ln(3+) modified TiO2 nanomaterials using fluorescence based technique has rarely been reported. In the present work, xmol Ln(3+) modified TiO2 nanomaterials (Ln = Nd(3+), Sm(3+), Eu(3+), Gd(3+), Dy(3+) and Er(3+) ions; x = 0.005, 0.008, 0.01, 0.02 and 0.03) were synthesized by sol-gel method and characterized using different advanced techniques. The photocatalytic efficiency of the modified TiO2 expressed in the charge carrier separation and OH radicals formation were assigned using TiO2 fluorescence quenching and fluorescence probe methods, respectively. The obtained fluorescence measurements confirm that doping treatment significantly decreases the electron-hole recombination probability in the obtained Ln(3+)/TiO2. Moreover, the rate of OH radicals formation is increased by doping. The highly active nanoparticles (0.02Gd(3+)/TiO2 and 0.01Eu(3+)/TiO2) were applied for industrial wastewater treatment using solar radiation as a renewable energy source.

High quality sulfur-doped titanium dioxide nanocatalysts with visible light photocatalytic activity from non-hydrolytic thermolysis synthesis

A non-hydrolytic route for monodisperse S-doped TiO₂ nanocatalysts with enhanced visible light activation is demonstrated.

Study on the optical property and surface morphology of N doped TiO₂ film deposited with different N₂ flow rates by DCPMS

N doped TiO2 films were deposited by direct current pulse magnetron sputtering system at room temperature. By using UV-Vis spectrophotometer and atomic force microscope, we studied the influence of N2 flow rate on the optical property and surface morphology of films. The results indicate that the optical property and surface morphology of N doped TiO2 film was dominated by the N2 flow rate. The mean absorbency in visible range of pure TiO2 films is near to 0%, which means that the pure TiO2 could hardly display the photocatalytic property in visible range. When N2 flow rate is 2 sccm, the mean absorbency in visible range of N doped TiO2 film could reach at 24%. In this case, the film could be used as photocatalyst induced by visible light. While with increasing N2 flow rate, the mean absorbency in visible range of N doped TiO2 film decreased abruptly. Especially when N2 flow rate exceeded 8 sccm, the mean absorbency in visible range of N doped TiO2 film decreased to about 0%, which is like pure TiO2 fimls.

Antifungal activity and mechanism of palladium-modified nitrogen-doped titanium oxide photocatalyst on agricultural pathogenic fungi Fusarium graminearum

Fusarium graminearum is the pathogen for Fusarium head blight (FHB) on wheat, which could significantly reduce grain quality/yield and produce a variety of mycotoxins posing a potential safety concern to human foods. As an environmentally friendly alternative to the commonly used chemical fugicides, a highly effective photocatalytic disinfection of F. graminearum macroconidia under visible light illumination was demonstrated on a visible-light-activated palladium-modified nitrogen-doped titanium oxide (TiON/PdO) nanoparticle photocatalyst. Because of the opposite surface charges of the TiON/PdO nanoparticles and the F. graminearum macroconidium, the nanoparticles were strongly adsorbed onto the macroconidium surface, which is beneficial to the photocatalytic disinfection of these macroconidia. The photocatalytic disinfection mechanism of TiON/PdO nanoparticles on these macroconidia could be attributed to their cell wall/membrane damage caused by the attack from reactive oxygen species (ROSs) as demonstrated by the fluorescence/phase contrast microscopy observations, while a breakage of their cell structure was not necessary for their loss of viability.

Influence of visible-light irradiation on physicochemical and photocatalytic properties of nitrogen-doped three-dimensional (3D) titanium dioxide

We report highly active visible-light driven nitrogen-doped three-dimensional polycrystalline anatase TiO2 photocatalysts (N-3D TiO2) for environmental and biomedical applications. N-3D TiO2 is synthesized at a low temperature (<90°C) without thermal treatment via a modified hydrothermal process (HP) and ultrasound irradiation (UI). The N-3D TiO2 is additionally irradiated with visible-light to improve the hydroxylation of its surface. Under visible-light irradiation, the photocatalytic activity of visible-light irradiated N-3D TiO2 (*N-3D TiO2; [k]=1.435 h(-1)) is 26.1 times higher than that of 3D TiO2 ([k]=0.055 h(-1)). The *N-3D TiO2 is highly recyclable and retained 91.8% of the initial decolorization rate after fifteen cycles. Interestingly, the *N-3D TiO2 shows very strong antibacterial properties against both Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) after exposure to visible-light for 3h. The antibacterial properties of *N-3D TiO2 are more effective than those of TiO2, 3D TiO2, and N-3D TiO2. More than 91.3% of the E. coli is sterilized after ten cycles. There are a large increase in the photocatalytic and antibacterial activity of *N-3D TiO2 relative to that of N-3D TiO2 owing to the hydroxylation of the N-3D TiO2 surface as a result of the visible-light irradiation. These results indicate that *N-3D TiO2 might have utility in several promising applications such as highly efficient water/air treatment, inactivation of pathogenic microorganisms, and solar-energy conversion.

Quantum-dot-sensitized TiO2 inverse opals for photoelectrochemical hydrogen generation

A new nanoarchitecture photoelectrode design comprising CdS quantum-dot-sensitized, optically and electrically active TiO(2) inverse opals is developed for photoelectrochemical water splitting. The photoelectrochemical performance shows high photocurrent density (4.84 mA cm(-2) at 0 V vs. Ag/AgCl) under simulated solar-light illumination.

Composition and crystal structure of N doped TiO2 film deposited at different O2 flow rate by direct current sputtering

N doped Ti02 films were deposited by direct current pulse magnetron sputtering system at room temperature. The influence of 02 flow rate on the crystal structure of deposited films was studied by Stylus profilometer, X-ray photoelectron spectroscopy, and X-ray diffractometer. The results indicate that the 02 flow rate strongly controls the growth behavior and crystal structure of N doped Ti02 film. It is found that N element mainly exists as substitutional doped state and the chemical stiochiometry is near to TiO1.68±0.06N0.11±0.01 for all film samples. N doped Ti02 film deposited with 2 sccm (standard-state cubic centimeter per minute) 02 flow rate is amorphous structure with high growth rate, which contains both anatase phase and rutile phase crystal nucleuses. In this case, the film displays the mix-phase of anatase and rutile after annealing treatment. While N doped Ti02 film deposited with 12 cm(3)/min 02 flow rate displays anatase phase before and after annealing treatment. And it should be noticed that no TiN phase appears for all samples before and after annealing treatment.