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Pure cubic In2O3, orthorhombic InOOH and cubic In(OH)3nanocrystals were separately synthesized viaa one-pot aqueous solvothermal route at low temperature by simply regulating the amount of water in the ternary system H2O–DMF–In(NO3)3·4.5H2O. [ABSTRACT FROM AUTHOR]

A composited system was fabricated by coupling Pt/TiO2 with water-splitting catalyst for photooxidation of organic pollutants in aqueous solutions. The new composited system exhibits more efficient photocatalytic activity than pure Pt/TiO2 does under UV light irradiation. The promoting effect is dependent on the photo-produced H2 over the composited system. The active oxygen species, hydroxyl radical (·OH) and hydrogen peroxide (H2O2), are measured by fluorescence spectroscopy and photometric method, respectively. The results reveal that the produced H2 by photocatalytic water splitting over NiO/NaTaO3:La transfers to Pt particle of TiO2 surface, then reacts with introducing O2 to generate in situ intermediate H2O2, and finally translates into ·OH radical to accelerate the photooxidation of organic pollutants. [ABSTRACT FROM AUTHOR]

A composited system was fabricated by coupling Pt/TiO2 with water-splitting catalyst for photooxidation of organic pollutants in aqueous solutions. The new composited system exhibits more efficient photocatalytic activity than pure Pt/TiO2 does under UV light irradiation. The promoting effect is dependent on the photo-produced H2 over the composited system. The active oxygen species, hydroxyl radical (·OH) and hydrogen peroxide (H2O2), are measured by fluorescence spectroscopy and photometric method, respectively. The results reveal that the produced H2 by photocatalytic water splitting over NiO/NaTaO3:La transfers to Pt particle of TiO2 surface, then reacts with introducing O2 to generate in situ intermediate H2O2, and finally translates into ·OH radical to accelerate the photooxidation of organic pollutants. [ABSTRACT FROM AUTHOR]

TiO2films on Al alloy (Al), indium-tin oxide glass (ITO/glass), and glass were prepared by a dip-coating method. ITO is found to have a higher work function, while the work function for Al is lower than that of TiO2films. An electron transfer is indicated to occur in the interfaces between TiO2films and conducting substrate Al or ITO, which results in an Ohm contact or Schottky barrier under the transient equilibrium UV radiation conditions. Photocatalytic measurements showed that the TiO2films on Al have a higher activity for photocatalytic oxidation of C2H4, but the activity for photocatalytic degradation of oleic acid is lower as compared with TiO2films on glass. Alternatively, TiO2films on ITO give completely contrary photocatalytic performance to those on Al. These observations could be associated with the electron transfer, in which Al acts as an electron donor and offers electrons to TiO2, allowing photocatalytic oxidation of ethylene to proceed by the photogenerated electrons, while ITO could be an acceptor for the photogenerated electrons, which is beneficial to photocatalytic degradation of oleic acid by the photogenerated holes. This electron-transfer model could be extended to other photocatalytic systems. [ABSTRACT FROM AUTHOR]

Cu(ii)/MCM-41, Cu(i)/MCM-41 and Cu(0)/MCM-41 materials were prepared with Cu[OCHMeCH2NMe2]2/MCM-41 as precursor under controlled conditions. The states of copper on the resulting samples were characterized by temperature programmed reduction (TPR), UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS), X-ray photoelectron spectroscopy (XPS), photoluminescence spectroscopy (PL), infrared spectroscopy (FTIR) of NO and CO adsorption, X-ray diffraction (XRD), and N2adsorption. It was shown that pure Cu(ii)/MCM-41 can be acquired by calcining Cu[OCHMeCH2NMe2]2/MCM-41 in pure oxygen at 573 K. Pure Cu(i)/MCM-41 can be obtained by reducing the as-prepared Cu(ii)/MCM-41 in a CO/He atmosphere at 473 K, while pure Cu(0)/MCM-41 can be obtained viareduction of the Cu(ii)/MCM-41 in a CO/He atmosphere at 673 K. The Cu(ii)–O and Cu(i)–O species were showed to be highly dispersed on the surface of MCM-41 as isolated sites. The study provides an alternative method for the preparation of pure copper metal or copper oxide supported materials. [ABSTRACT FROM AUTHOR]

Close proximity between different catalytic sites is crucial for accelerating or even enabling many important catalytic reactions. Photooxidation and photoreduction in photocatalysis are generally separated from each other, which arises from the hole-electron separation on photocatalyst surface. Here, we show with widely studied photocatalyst Pt/TiO2 as a model, that concentrating abundant oxygen vacancies only at the metal-oxide interface can locate hole-driven oxidation sites in proximity to electron-driven reduction sites for triggering unusual reactions. Solar hydrogen production from aqueous-phase alcohols, whose hydrogen yield per photon is theoretically limited below 0.5 through conventional reactions, achieves an ultrahigh hydrogen yield per photon of 1.28 through the unusual reactions. We demonstrated that such defect engineering enables hole-driven CO oxidation at the Pt- TiO2 interface to occur, which opens up room-temperature alcohol decomposition on Pt nanoparticles to H2 and adsorbed CO, accompanying with electron-driven proton reduction on Pt to H2. [ABSTRACT FROM AUTHOR]

This work shows a novel artificial donor-catalyst- acceptor triad photosystem based on a mononuclear C5H5- RuH complex oxo-bridged TiO2 hybrid for efficient CO2 photoreduction. An impressive quantum efficiency of 0.56% for CH4 under visible-light irradiation was achieved over the triad photocatalyst, in which TiO2 and C5H5-RuH serve as the electron collector and CO2-reduction site and the photonharvester and water-oxidation site, respectively. The fast electron injection from the excited Ru2+ cation to TiO2 in ca. 0.5 ps and the slow backward charge recombination in half-life of ca. 9.8 ms result in a long-lived D+-C-A- charge-separated state responsible for the solar-fuel production. [ABSTRACT FROM AUTHOR]

By deposition of Au nanoparticles (Au NPs) onto BiOCl (BOC) nanosheet with different facets, in the reaction of decomposing Orange II, we systematically investigated the preferred transfer orientation (PTO) of photo-generated electron--hole pairs in BOC under UV light irradiation. Also, the active oxidative intermediates during the degradation process were also studied. Moreover, the Au NPs successfully brought about visible light response to the wide gap BOC, while the exposed different facets were found to be influential on the surface plasmon resonance (SPR) effect. The present work may contribute to a deeper sight of the relationship between specific facets and photocatalytic performance, together with a further understanding of SPR-induced photocatalytic activity. [ABSTRACT FROM AUTHOR]

Well-defined Zn2Ge04 hexagonal nanorods and nanofibers with high aspect ratios have been readily realized in high yield via a simple and general hydrothermal synthesis method free of any surfactant or template. Field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectrometry (EDX), powder X-ray diffraction (XRD), and ultraviolet-visible light diffuse reflectance spectroscopy (UV--vis DRS) revealed a unique hexagonal-prism-shaped one-dimensional (1-D) structure, surface features, anisotropic crystal growth, and crystal phase of Zn2Ge04. Detailed investigations indicated that the prismatic Zn2Ge04 nanocrystais are uniform single crystal with the longitudinal direction along the [001 ] and were dominated by (HO) and (TTO) surfaces. The addition of increasing amounts of NaOH was found to facilitate the morphology transition from a hexagonal nanorod shape to a hexagonal fiber shape. As an important wide-band-gap photocatalyst, the products of regular Zn2Ge04 nanocrystais with a hexagonal 1-D structure exhibit superior photocatalytic activities for the photocatalytic decomposition of water--methanol solution to hydrogen under UV irradiation. [ABSTRACT FROM AUTHOR]

The C-doped CdO photocatalysts were simply prepared by high-temperature solid-state process. The as-prepared photocatalysts were characterized by X-ray powder diffraction (XRD), diffuse reflectance spectroscopy (UV-Vis DRS), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results demonstrated that the carbon was doped into CdO, resulting in the red-shift of the optical absorption of CdO. The photocatalytic behavior of CdO and C-doped CdO was evaluated under the visible light irradiation by using the photocatalytic hydrogen evolution as a model reaction. The C-doped CdO photocatalysts had higher photocatalytic activity over parent CdO under visible light irradiation. The results indicated that the H2 production was due to the existence of CdS and the enhancement of visible light photocatalytic activity of H2 production was originated from the doping of carbon into the CdO lattice. The probably reaction mechanism was also discussed and proposed. [ABSTRACT FROM AUTHOR]

Cubic ZnIn2S4nanoparticles and hexagonal ZnIn2S4flower-like microspheres were controlled synthesized viaa facile hydrothermal method by simply changing the metal precursors. The as-prepared samples were characterized by XRD, SEM, TEM and UV-vis DRS. It was found that the metal precursors influenced the final ZnIn2S4polymorphs, i.e., metal nitrates led to the formation of cubic ZnIn2S4, while metal chlorides resulted in the formation of the hexagonal phase. The formation processes of the cubic ZnIn2S4nanoparticles and hexagonal ZnIn2S4flower-like microspheres were investigated and the mechanism of the phase formation was proposed. Although both cubic and hexagonal ZnIn2S4polymorphs exhibited photocatalytic activity for the degradation of methyl orange (MO) under visible light irradiation, the photocatalytic performances over cubic and hexagonal ZnIn2S4were different. [ABSTRACT FROM AUTHOR]

Nanosized porous In(OH)3 photocatalysts with high surface areas (as much as 110 m²∙g-1) were successfully synthesized by peptization of colloidal precipitates under ultrasound radiation. The resulting catalysts were characterized by X-ray powder diffraction (XRD), thermogravimetric analysis, nitrogen adsorption, transition electron microscopy, and UV—vis diffuse reflection spectroscopy. The photocatalytic activities of the samples were evaluated by the gas-phase decomposition of several volatile organic pollutants (acetone, benzene, and toluene) under UV light illumination and were compared with that of the commercial titania (Degussa P25). Results revealed that the as-synthesized In(OH)3 exhibited much higher photocatalytic activity and durability than both In2O3 and TiO2. One, therefore, can conclude that nanosized In(OH)3 has potential application in environmental treatment, especially in the removal of benzene-containing exhaust emissions from shoemaking plants in China. The excellent photocatalytic performance of In(OH)3 can be attributed to its strong oxidation capability, abundant surface hydroxyl groups, and high BET surface area as well as the porous texture. [ABSTRACT FROM AUTHOR]

The deposition of an organic copper precursor Cu[OCHMeCH 2NMe 2] 2on the surface of mesoporous silica MCM-41 dehydrated at 773 K was studied under high-vacuum conditions by infrared spectroscopy combined with elemental analysis, X-ray absorption spectroscopy (XAS), thermogravimetric analysis (TG), temperature-programmed decomposition (TPD), and X-ray photoelectron spectroscopy (XPS). It is revealed that the copper precursor is chemically adsorbed on the surface of MCM-41 to form a stable surface copper complex (SC1) coordinated with two framework oxygen atoms by ligand exchange at temperatures below 423 K. The surface copper complex is easily decomposed into Cu(I) and Cu(0) via a successive two-step pathway upon heating at temperatures beyond 423 K. IR and TPD results indicate that the first-step decomposition occurs at the temperature range from 423 to 523 K, where the surface complex SC1 loses one organic ligand and one methane molecule, leading to formation of a surface intermediate complex (SC2) with a Schiff base ligand. The second-step decomposition starts at 523 K, where the complex (SC2) is transformed to Cu(0) by losing the remanent organic ligand and undergoes a surface intermediate complex (SC3) to form Cu(I) oxide species by a consecutive loss of small molecules. The surface hydroxyl groups participate in the adsorption and reaction of the Cu precursor on the support MCM-41, which is a critical factor to controllable preparation of copper-containing MCM-41 catalysts. The mechanisms of thermolysis are suggested to be distinctly different from its MOCVD pathways reported in the literature. [ABSTRACT FROM AUTHOR]

An acid photocatalyst TiO2, modified with H2SO4, is prepared and used to decontaminate Chemical Warfare Agents (CWAs) simulants 2-CEES (2-chloroethyl ethyl sulfide) and DMMP (dimethyl methylphosphonate) in vapor phase. Compared with the unmodified pure TiO2 photocatalyst, the adsorption capacity on the sulfated photocatalyst increases by 50%, and the conversion for 2-CEES increases more than 20%. It is found that the durability for decontaminating DMMP is delayed by 200 min with the modified photocatalyst. The surface characteristics of the photocatalysts are analyzed by XPS and FT-IR. The results show that more Lewis and Brönsted acid sites, considered to be responsible for improving the reactivity performance of photocatalysts, are formed on the sulfated TiO2. [ABSTRACT FROM AUTHOR]

Multivalency iodine (I7/I-) doped TiO2were prepared via a combination of deposition−precipitation process and hydrothermal treatment. The as-prepared samples were characterized by X-ray diffraction, transmission electron microscopy, Brunauer−Emmett−Teller surface area, UV−vis diffuse reflectance spectra, X-ray photoelectron spectroscopy, surface photovoltage spectroscopy, and electric-field-induced surface photovoltage spectroscopy. The electronic structure calculations based on the density functional theory revealed that upon doping, new states that originated from the I atom of the IO4group are observed near the conduction-band bottom region of TiO2, and the excitation from the valence band of TiO2to the surface IO4-is responsible for the visible-light response of the I-doped TiO2. The as-prepared I-doped TiO2showed high efficiency for the photocatalytic decomposition of gaseous acetone under visible light irradiation ( > 420 nm). A possible mechanism for the photocatalysis on this multivalency iodine (I7/I-) doped TiO2under visible light was also proposed. [ABSTRACT FROM AUTHOR]

Pb3O4 could react with organic dyes in aqueous solution under visible light irradiation, in which Pb3O4 was transformed into Pb3(CO3)2(OH)2 along with oxidation of the organic dyes. Cu2+ has considerable effect on the reaction. In the presence of Cu2+, MO (20 ppm) and RhB (10-5 mol L-1) were completely degraded under visible light within 6 and 20 min, respectively, while both Pb3O4 and Cu2+ keep almost stable during photo-degradation. The mechanisms of the reactions with and without Cu2+ ions were studied. The photochemical system of Pb3O4 cooperating with Cu2+ ions is probably used for the treatment of organic pollutants in water under visible light. [ABSTRACT FROM AUTHOR]

Sequential impregnations of metal ions and titanium tetraisopropoxide (TTIP) into activated carbon fibers (ACF) followed by a solvothermal treatment has been found to be a general method in the preparations of homogeneous and composition-tunable hybrid TiO2hierarchical nanocomposite fibers like WO3/TiO2, Fe2O3/TiO2and SnO2/TiO2. [ABSTRACT FROM AUTHOR]