3 research outputs found

    Microemulsion-Assisted Synthesis of Mesoporous Aluminum Oxyhydroxide Nanoflakes for Efficient Removal of Gaseous Formaldehyde

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    Mesoporous aluminum oxyhydroxides composed of nanoflakes were prepared via a water-in-oil microemulsion-assisted hydrothermal process at 50 °C using aluminum salts as precursors and ammonium hydroxide as a precipitating agent. The microstructure, morphology, and textural properties of the as-prepared materials were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), nitrogen adsorption, and X-ray photoelectron spectroscopy (XPS) techniques. It is shown that the aluminum oxyhydroxide nanostructures studied are effective adsorbents for removal of formaldehyde (HCHO) at ambient temperature, due to the abundance of surface hydroxyl groups, large specific surface area, and suitable pore size. Also, the type of aluminum precursor was essential for the microstructure formation and adsorption performance of the resulting materials. Namely, the sample prepared from aluminum sulfate (Al-s) exhibited a relatively high HCHO adsorption capacity in the first run, while the samples obtained from aluminum nitrate (Al-n) and chloride (Al-c) exhibited high adsorption capacity and relatively stable recyclability. A combination of high surface area and strong surface affinity of the prepared aluminum oxyhydroxide make this material a promising HCHO adsorbent for indoor air purification

    Enhanced Photocatalytic CO<sub>2</sub>‑Reduction Activity of Anatase TiO<sub>2</sub> by Coexposed {001} and {101} Facets

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    Control of TiO<sub>2</sub> crystal facets has attracted enormous interest due to the fascinating shape-dependent photocatalytic activity of this material. In this work, the effect of the ratio of {001} and {101} facets on the photocatalytic CO<sub>2</sub>-reduction performance of anatase TiO<sub>2</sub> is reported. A new “surface heterojunction” concept is proposed on the basis of the density functional theory (DFT) calculations to explain the difference in the photocatalytic activity of TiO<sub>2</sub> with coexposed {001} and {101} facets

    Mesoporous TiO<sub>2</sub> Comprising Small, Highly Crystalline Nanoparticles for Efficient CO<sub>2</sub> Reduction by H<sub>2</sub>O

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    The conversion of CO<sub>2</sub> into hydrocarbon fuels with H<sub>2</sub>O using low-cost photocatalysts can offer a sustainable route to meet some of our energy needs, besides being able to contribute to the solutions of global warming. In this work, a series of highly crystalline mesoporous titanium dioxide (TiO<sub>2</sub>) photocatalysts are synthesized via a simple template-free synthetic method. The synthesis involves preparation of titanium glycolate microspheres (TGMs), then hydrolysis of the TGMs in boiling water under ambient pressure, and finally calcination of the products in air. The hydrolysis step is found to play a crucial role in the formation of TiO<sub>2</sub> microspheres comprising a network of small anatase grains. The hydrolysis of the TGMs is also found to considerably inhibit the possible phase transformation of anatase to rutile during the subsequent high-temperature crystallization process. The resulting materials have good crystallinity and efficient charge carrier separation capabilities, as well as large specific surface areas, and thus large density of accessible catalytically active sites. These unique structural features enable these materials to exhibit high photocatalytic activities for the conversion of CO<sub>2</sub> with H<sub>2</sub>O into hydrocarbon fuels (CH<sub>4</sub>) and to show much better catalytic activities than that of the commercial photocatalyst Degussa P25 TiO<sub>2</sub>