Multifunctionality in coating films including Nb-doped TiO2 and Cs x WO3: near infrared shielding and photocatalytic properties.

Various types of coating films were obtained from hydrothermally synthesized Nb-doped TiO2 (NTO) and Cs x WO3 (CWO) nanoparticles. The coating films possessed multifunctionality including near infrared (NIR) absorption and photocatalysis abilities. The NTO and CWO nanoparticles were synthesized by a unique solvothermal reaction in which water induced by an esterification reaction between alcohol and carboxylic acid can act as a hydrolyzing agent for metal precursors. NTO was synthesized by the unique solvothermal reaction for the first time. The reaction accompanied by the reduction of Ti4+ to Ti3+ led to the formation of nanoparticles with both NIR absorption and photocatalytic properties. The effect of the ethanol-acetic acid ratio on the morphology of the obtained NTO was investigated, and the larger amount of acetic acid led to a larger nanoparticle size, indicating the size controllability. The two types of coating film, including CWO and NTO nanoparticles, were obtained for comparison: (1) coexistent coating film: one side of the quartz glass was coated with a dispersion, including both CWO and NTO nanoparticles, and (2) double-sided coating film: a quartz glass coated with a CWO dispersion on one side and an NTO dispersion on the other side. The double-sided coating led to higher multifunctionality. Furthermore, the optimized condition for the double-sided coating was investigated by using various NTO particles obtained using different ethanol-acetic acid ratios.

Bi(1-x)Ni(x)VO(4-y) Solid Solution with a High Visible-Light Photocatalytic Activity for Degradation Methyl Orange.

Particulate solid solutions Bi(1-x)Ni(x)VO(4-y) were synthesized by solid-state reaction at high temperature. The samples were characterized by X-ray Diffraction (XRD), Field-Emission Scanning Electron Microscopy (FE-SEM), Energy Dispersive Spectrometer (EDS), Brunauer-Emmett-Teller (BET) surface area and Ultraviolet-Visible spectroscopy (UV-Vis). The photocatalytic activity of BiVO4 for photocatalytic degradation of organic contaminants ability in visible light region could be improved by doping of Ni(2+). The high visible light photocatalytic activity of Bi(1-x)Ni(x)VO(4-y) solid solution might be due to the generation of a new band gap and expanding the range of visible light response. It was suggested that the Ni(2+) doping was beneficial to effective charge separation of Bi(1-x)Ni(x)VO(4-y) solid solution, thus improved the photocatalytic activity.

Preparation and visible light induced photocatalytic activity of C-NaTaO3 and C-NaTaO3-Cl-TiO2 composite.

A nice visible light responsive C-doped NaTaO3 (C-NaTaO3) particle has been successfully prepared by a facile solvothermal method using water-ethylene glycol mixed solutions as solvent. The results presented that the carbon could be easily incorporated in NaTaO3 from ethylene glycol during a solvothermal reaction, finally leading to excellent visible light absorption. The as-synthesized C-NaTaO3 showed excellent visible light induced photocatalytic activity superior to those of pure NaTaO3 and commercial P25. In addition, in order to further improve the visible light driven photocatalytic performance of C-NaTaO3, a new C-doped NaTaO3-Cl-doped TiO2 (C-NaTaO3-Cl-TiO2) core-shell type of composite was also fabricated. After coupling C-NaTaO3 with Cl-TiO2, the visible light induced NOx gas destruction ability of C-NaTaO3-Cl-TiO2 composite was significantly enhanced as compared to those of sole C-NaTaO3 and Cl-TiO2, probably due to the hindrance of the recombination rate of photogenerated electron-hole pairs. The C-NaTaO3 particle and C-NaTaO3-Cl-TiO2 composite prepared in this work would probably provide a new way to prepare high performance of visible light induced perovskite-type NaTaO3 based photocatalysts.

Solvothermal fabrication of rubidium tungsten bronze for the absorption of near infrared light.

For fabricating the crystal of Rb(x)WO3, the solvothermal process was performed using a mixed medium of water and ethanol as solvent. It has been found that the morphological evolutions of samples were greatly changed as disordered nanoparticles, bundle of nanorods and microfibers with increasing content of water in the starting solution. Among them, sample synthesized with assistance of 3 ml water consisted of the nanorods with a diameter in the range of 80-150 nm, showing suitable size and morphology as near-infrared shielding material. On the merits of this nanostructure, the thin film of the Rb(x)WO3 nanorods realized excellent shielding of near-infrared light, meanwhile, it selectively transmitted the major part of visible light.

Morphology-controlled synthesis of W18O49 nanostructures and their near-infrared absorption properties.

The morphology-controlled synthesis and near-infrared (NIR) absorption properties of W(18)O(49) were systematically investigated for the application of innovative energy-saving windows. Various morphologies of W(18)O(49), such as nanorods, nanofibers, nanograins, nanoassembles, nanoplates, and nanoparticles, with various sizes were successfully synthesized by solvothermal reactions using organic alcohols as reaction media and WCl(6), W(EtO)(6), and WO(3) solids as the tungsten source. W(18)O(49) nanorods of less than 50 nm in length showed the best optical performance as an effective solar filter, which realized high transmittance in the visible region as well as excellent shielding properties of NIR light. Meanwhile, the W(18)O(49) nanorods also exhibited strong absorption of NIR light and instantaneous conversion of the absorbed photoenergy to the local heat.

Persistent fluorescence-assisted TiO2-xNy-based photocatalyst for gaseous acetaldehyde degradation.

Photocatalytic technologies were utilized to develop an environment-friendly system that is capable of removing and oxidizing organic pollutants from an air stream. A series of long-afterglow phosphors emitting long lifetime fluorescence was adapted to prepared TiO(2)-based composite photocatalysts for the photodegradation of gas-phase acetaldehyde. Although the photocatalytic reaction by an undoped titania (Degussa P25) was stopped immediately after turning off the irradiation light, the long-afterglow phosphor/nitorogen-doped TiO(2) (TiO(2-x)N(y)) composites maintained the acetaldehyde photodegradation ability even after turning off the light for a long time. This novel photocatalytic property may be attributed to the presence of the long-afterglow phosphor, which can reserve the light energy and generate the persistent fluorescence afterward as the light source for the photocatalytic reaction with the visible-light responsive TiO(2-x)N(y). The substitution of the undoped TiO(2) with TiO(2-x)N(y) was essential to use the fluorescence as a light source for photocatalysis. Such a self-fluorescence-assisted system could enhance the performance of photocatalysts for environmental cleanup.

Synthesis of C-N co-doped nano-CeO2 and dye degradation under compact fluorescent lamp irradiation.

Carbon and nitrogen (C-N) co-doped nano-CeO2 was synthesized by the solvothermal method using hexamethylenetetramine (HMT) as a precipitator at 140 degrees C for 24 h. We found that the degradation of acid orange 7 (AO7) was 94.4% and 98.8% with C-N co-doped nano-CeO2 upon irradiation with a 100-watt high-pressure mercury lamp (HML) and a 10-watt compact fluorescent lamp (CFL), respectively. By comparison, TiO2 degraded 68.4% and 43.0% of the AO7 irradiated by HML and CFL, respectively. We found that the degradation efficiencies of AO7 upon irradiation with the 10-watt CFL in the presence of the samples synthesized using different precipitators decreased as follows: CeO2(HMT)> CeO2-TiO2(HMT) > TiO2(HMT) >> CeO2(NaHCO3) > CeO2(Na2CO3).

Synthesis of W18O49 nanorod via ammonium tungsten oxide and its interesting optical properties.

W(18)O(49) nanorods were synthesized by pyrolyzing (NH(4))(x)WO(3+x/2) nanorods precursors, which were prepared by a hydrothermal reaction using sulfate as a structure-directing agent, in a reductive atmosphere of H(2)(5 vol %)/N(2) at 500 °C for 1 h. W(18)O(49) nanorods showed high transmittance in the visible region as well as excellent shielding properties of NIR lights. A simulated experiment revealed that excellent heat insulating performance can be realized by applying a 70% visible light transparent W(18)O(49) coating on a quartz glass. Meanwhile, the W(18)O(49) nanorods also showed strong absorption of NIR light and instantaneous conversion of photoenergy to heat. In a word, W(18)O(49) nanorods hold interesting optical properties and are a promising material in a wide range of applications.

Eu3+:Y2O3 microspheres and microcubes: a supercritical synthesis and characterization.

A new approach that uses mixed supercritical solvents of water/1-propanol and water/methanol (400 °C, 40 MPa) to prepare morphology-controlled precursor materials in a very short reaction time, such as 10 min, followed by calcinations has been developed to form Eu(3+):Y(2)O(3) microspheres of 2-3 µm in diameter or microcubes of 2-3 µm in side length, respectively. Eu(3+):Y(2)O(3) microspheres and microcubes exhibited strong red emission at 610 nm corresponding to (5)D(0) → (7)F(2) transition. The highest photoluminescence emission was obtained for the microspheres after calcination at 1000 °C for 1 h in air.

Soft solution synthesis of ZnO films with developed superstructures.

A novel and simple two-step solution approach to prepare ZnO thin film consisted of 3D flower-like superstructure was demonstrated. The uniform, nano-dimensional scale and sphere-like ZnO crystals were first prepared on the borosilicate glass substrate in mild solution at 95 degrees C for 3 h, then introduced into 0.02 mol L(-1) hexamethylenetetramine (HMT, C6H12N4) aqueous solution and heated at the same temperature for 3 d. The obtained ZnO thin films were characterized by XRD, SEM and photoluminescence. The results indicated that the thin film with 3D flower-like superstructure possessed high crystallinity, high surface-volume ratio microstructure and excellent photoluminescence property. It is a potential way to prepare nano-structured materials by the mentioned simple and novel two-step solution synthesis process.

Solvothermal synthesis and characterization of Eu3+ doped Y2O3 nanocrystals.

A solvothermal refluxing system containing of ethylene glycol and ethylene glycol-hexane mixed organic solvents were used to prepare Eu3+ doped Y2O3 nanocrystals via solvothermal refluxing reaction-calcinations method. In the presence of ethylene glycol, the reaction temperature required for the preparation of Y(OH)3 precursor crystal is 170 degrees C but in ethylene glycol-hexane mixed organic solvents, the synthesis temperature was reduced to 70 degrees C. The Y(OH)3 precursor particles were calcinated at 600-1200 degrees C in air to prepare nanosized Eu3+ doped Y2O3 red phosphor. The as prepared particles by refluxing in ethylene glycol followed by calcination showed 20-60 nm in diameter. For the characterization, XRD, TG-DTA, EDS, FTIR, TEM and PL measurements were employed. The as prepared sample by refluxing in ethylene glycol-hexane mixed solvents exhibited strong red emission around 610 nm under 254 nm xenon light excitation and photoluminescence property was compared with reference sample (5 mol% Eu3+:Y2O3) prepared via conventional co-precipitation method followed by calcinations at 800 degrees C for 5 h in air.

An all-solid-state dye-sensitized solar cell-based poly(N-alkyl-4-vinyl-pyridine iodide) electrolyte with efficiency of 5.64%.

Using poly(N-methyl-4-vinyl-pyridine iodide), N-methyl-pyridine iodide and iodine, a solid polymer electrolyte with conductivity of 6.41 mS/cm is prepared. On the basis of a solid polymer electrolyte, a conducting graphite layer, a KI block layer, and a vacuum assembling technique, we achieve an all-solid-state dye-sensitized solar cell with total photoelectric conversion efficiency of 5.64% under AM 1.5 simulated solar light (100 mW/cm2) illumination.

Photocatalytic NO removal over calcium-bridged siloxenes under ultraviolet and visible light irradiation.

Ca-Bridged siloxenes (Ca-siloxenes) composed of two-dimensional siloxene planes with Ca bridging were prepared and their photocatalytic properties for nitrogen oxide (NO) removal were investigated. Ca-Siloxenes were synthesized via a solid-state metathesis reaction using TaCl5 to extract Ca from CaSi2 with different Cl2/Ca molar ratios of 0.25, 1.25 and 2.5 (CS0.25, CS1.25 and CS2.5, respectively) in an attempt to control the extent of Ca extraction. Ca-Siloxenes have a wide optical absorption band from the visible to ultraviolet region with absorption edges of 1.5, 2.9, and 3.1 eV for CS0.25, CS1.25, and CS2.5, respectively. Ca-Siloxenes exhibited photocatalytic activity for NO removal under irradiation with visible (λ > 400 nm (<3.10 eV)) and ultraviolet light (λ > 290 nm (<4.28 eV)). The photocatalytic activity was particularly improved by mixing the Ca-siloxene with acetylene black as a conductive material, which might have inhibited the recombination of photogenerated electrons and holes. The mixture of Ca-siloxene and acetylene black exhibited improved photocatalytic activity in the presence of 1O2 as one of the active oxygen species formed under ultraviolet light irradiation.

A P25/(NH4)xWO3 hybrid photocatalyst with broad spectrum photocatalytic properties under UV, visible, and near-infrared irradiation.

In this study, a series of hybrid nanostructured photocatalysts P25/(NH4)xWO3 nanocomposites with the average crystallite size of P25 and (NH4)xWO3 of the sample was calculated to be about 30 nm and 130 nm, were successfully synthesized via a simple one-step hydrothermal method. The as-obtained samples was characterized by transmission electron microscopy (TEM), which implies that the P25/(NH4)xWO3 nanocomposites are fabricated with favourable nanosizd interfacial. The XPS results confirmed that the obtained sample consists of mixed chemical valences of W5+ and W6+, the low-valance W5+ sites could be the origin of NIR absorption. As revealed by optical absorption results, P25/(NH4)xWO3 nanocomposites possess high optical absorption in the whole solar spectrum of 200-2500 nm. Benefiting from this unique photo-absorption property and the synergistic effect of P25 and (NH4)xWO3, broad spectrum response photocatalytic activities covering UV, visible and near infrared regions on degradation of Rhodamine B have been realized by P25/(NH4)xWO3 nanocomposites. Meanwhile, the stability of photocatalysts was examined by the XRD and XPS of the photocatalysts after the reaction. The results show that P25/(NH4)xWO3 photocatalysts has a brilliant application prospect in the energy utilization to solve deteriorating environmental issues.

Photocatalytic activity of silicon-based nanoflakes for the decomposition of nitrogen monoxide.

The photocatalytic decomposition of nitrogen monoxide (NO) was achieved for the first time using Si-based nanomaterials. Nanocomposite powders composed of Si nanoflakes and metallic particles (Ni and Ni3Si) were synthesized using a simple one-pot reaction of layered CaSi2 and NiCl2. The synthesized nanocomposites have a wide optical absorption band from the visible to the ultraviolet. Under the assumption of a direct transition, the photoabsorption behavior is well described and an absorption edge of ca. 1.8 eV is indicated. Conventional Si and SiO powders with indirect absorption edges of 1.1 and 1.4 eV, respectively, exhibit considerably low photocatalytic activities for NO decomposition. In contrast, the synthesized nanocomposites exhibited photocatalytic activities under irradiation with light at wavelengths >290 nm (<4.28 eV). The photocatalytic activities of the nanocomposites were confirmed to be constant and did not degrade with the light irradiation time.

Silica coating and photochemical properties of layered double hydroxide/4,4'-diaminostilbene-2,2'-disulfonic acid nanocomposite.

Organic ultraviolet (UV) rays absorbents have been used as sunscreen materials, but they may pose a safety problem when used at high concentration. In order to prevent direct contact of organic UV rays absorbent to the human skin, a typical organic UV-absorbent, 4,4(')-diaminostilbene-2,2(')-disulfonic acid (DASDSA), was intercalated into Zn(2)Al layered double hydroxide (Zn(2)Al-LDH) by coprecipitation reaction. However, deintercalation of DASDSA from Zn(2)Al-LDH, by the anion exchange reaction with carbonate ion, was observed. Therefore, Zn(2)Al-LDH/DASDSA was directly coated with silica by means of polymerization technique based on the Stöber method. Silica coating effectively depressed the deintercalation of DASDSA from Zn(2)Al-LDH. The amorphous silica was confirmed by XRD, SEM, TEM and FT-IR. The deintercalation behaviors as well as UV-shielding properties were investigated for coated particles.

Control of silica shell thickness and microporosity of titania-silica core-shell type nanoparticles to depress the photocatalytic activity of titania.

Titania is of potential interest as an ultraviolet (UV) radiation blocking material in personal care products because of its excellent UV light absorption properties. Its high photocatalytic activity, however, facilitates the generation of reactive oxygen species, which can oxidize and degrade other ingredients during its formulation, raising safety concerns. Dense coating of titania nanoparticles with a silica layer could help in depression of their photocatalytic activity by disturbing the formation of radicals produced by the reaction of oxygen and/or water with the electron-hole pair. Depression of the high photocatalytic activity of titania necessitates that the silica shell has to be thick, with minimum microporosity. Coating parameters were optimized to attain greater amounts of precipitated silica and thicker shells with lower microporosity, which in turn resulted in great depression of photocatalytic activity. Silica-coated titania nanoparticles were characterized by TEM, XPS, FT-IR, EDX, and microporosity measurements. The photocatalytic activity was evaluated for the coated powder to investigate the efficiency of the silica coating as well.

[Status of measures against angiography room infection as determined by questionnaire].

Although the cleanliness of the angiography room and that of the operating room have long been equally attended to, the concept of Standard Precautions (including the basic measures and procedures to prevent infection) of the Centers for Disease Control and Prevention (CDC), 1996, as well as the introduction of transmission-based precautions, have been changing to preventive measures that are based on concrete measures. Therefore, a questionnaire was introduced in order to determine the actual status of countermeasures against infection used in the angiography room. The questionnaire was sent to 530 institutions, and 286 responded, a response rate of 54.0%. Its results significantly revealed the following: 1) unexpectedly low recognition of the need and importance for the CDC preventive measures against infection, 2) a considerable number of institutions continuing to perform the conventional preventive measures, 3) problems with education systems on preventive measures, and 4) handwashing, the most important measure against infection, failing to be adequately carried out noticeably among radiological technologists.

Enhanced Photocatalytic Performance of Luminescent g-C3N4 Photocatalyst in Darkroom.

Graphitic-C3N4(g-C3N4), a low-cost visible-light-driven photocatalyst, was used for the photocatalytic oxidation of aqueous methylene blue (MB) in the dark with Sr4Al14O25:(Eu,Dy) assistance. The Sr4Al14O25:(Eu,Dy)/g-C3N4 photocatalysts were fabricated through the ultrasonic dispersion method. The commercial Sr4Al14O25:(Eu,Dy) phosphor was used as a long afterglow supplier for exciting g-C3N4 in the dark. The results demonstrated that the metal-free g-C3N4 photocatalyst could use the eye-visible long afterglow to photocatalytically decompose MB dyes in the dark. This work may expand the appealing application of g-C3N4 for the environmental cleanup.

Smart window coating based on F-TiO2-KxWO3 nanocomposites with heat shielding, ultraviolet isolating, hydrophilic and photocatalytic performance.

A series of smart window coated multifunctional NIR shielding-photocatalytic films were fabricated successfully through KxWO3 and F-TiO2 in a low-cost and environmentally friendly process. Based on the synergistic effect of KxWO3 and F-TiO2, the optimal proportion of KxWO3 to F-TiO2 was investigated and the FT/2KWO nanocomposite film exhibited strong near-infrared, ultraviolet light shielding ability, good visible light transmittance, high photocatalytic activity and excellent hydrophilic capacity. This film exhibited better thermal insulation capacity than ITO and higher photocatalytic activity than P25. Meanwhile, the excellent stability of this film was examined by the cycle photocatalytic degradation and thermal insulation experiments. Overall, this work is expected to provide a possibility in integrating KxWO3 with F-TiO2, so as to obtain a multifunctional NIR shielding-photocatalytic nanocomposite film in helping solve the energy crisis and deteriorating environmental issues.