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Photocatalytic Hydrogen Production in Water-Methanol Mixture over Iron-doped CaTiO_3
장점석,P. H. Borse,이재성,임권택,정옥상,정의덕,배종성,김현규 대한화학회 2011 Bulletin of the Korean Chemical Society Vol.32 No.1
CaTi1-xFexO3 (0 ≤ x ≤ 0.4) solid solution photocatalysts were synthesized by iron doping during the conventional solid state reaction at 1100 ^oC for 5 h and characterized by ultraviolet-visible (UV-vis) absorption spectroscopy, X-ray diffraction,morphological analysis. We found that CaTi1-_xFe_xO_3 samples not only absorb UV but also the visible light photons. This is because the Fe substitution at Ti-site in CaTi1-xFexO3 lattice induces the band transition from Fe3d to the Fe3d +Ti3d hybrid orbital. The photocatalytic activity of Fe doped CaTiO_3 samples for hydrogen production under UV light irradiation decreased with the increase in the Fe concentration. There exists an optimized concentration of iron in CaTiO_3,which yields a maximum photocatalytic activity under visible light (λ ≥ 420 nm) photons.
장점석,Pramod H. Borse,이재성,정옥상,조채용,정의덕,Myoung Gyu Ha,원미숙,김현규 대한화학회 2009 Bulletin of the Korean Chemical Society Vol.30 No.8
Nanocrystalline ZnFe2O4 oxide-semiconductor with spinel structure was synthesized by the polymerized complex (PC) method and investigated for its photocatalytic and photoelectric properties. The observation of a highly pure phase and a lower crystallization temperature in ZnFe2O4 made by PC method is in total contrast to that was observed in ZnFe2O4 prepared by the conventional solid-state reaction (SSR) method. The band gap of the nanocrystalline ZnFe2O4 determined by UV-DRS was 1.90 eV (653 nm). The photocatalytic activity of ZnFe2O4 prepared by PC method as investigated by the photo-decomposition of isopropyl alcohol (IPA) under visible light (≥ 420 nm) was much higher than that of the ZnFe2O4 prepared by SSR as well as TiO2-xNx. High photocatalytic activity of ZnFe2O4 prepared by PC method was mainly due to its surface area, crystallinity and the dispersity of platinum metal over ZnFe2O4.
Energy Band Structure and Photocatalytic Property of Fe-doped Zn2TiO4 Material
장점석,Pramod H. Borse,이재성,임권택,정옥상,정의덕,Jong Seong Bae,원미숙,김현규 대한화학회 2009 Bulletin of the Korean Chemical Society Vol.30 No.12
Zn2Ti1-xFexO4 (0 ≤ x ≤ 0.7) photocatalysts were synthesized by polymerized complex (PC) method and investigated for its physico-chemical as well as optical properties. Zn2Ti1-xFexO4 can absorb not only UV light but also visible light region due to doping of Fe in the Ti site of Zn2TiO4 lattice because of the band transition from Fe 3d to the Fe 3d + Ti3d hybrid orbital. The photocatalytic activity of Fe doped Zn2TiO4 samples for hydrogen product ion under UV light irradiation decreased with an increase in Fe concentration in Zn2TiO4. Consequently, there exists an optimized concentration of iron for improved photocatalytic activity under visible light (λ ≥ 420 nm)
장점석,권민석,김현규,박재욱,이재성 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.5
The titanate nanotube (TNT) was hydrothermally synthesized in 10 M NaOH aqueous solution at 150 oC for 72 h. Titanate nanotube with high surface area (292 m2/g) is a good candidate as a support for catalytic reaction or organic synthesis. Palladium nanoparticles with an average size of ca. 3 nm were well dispersed onto the surface of TNT nanotubes. Palladium loaded catalyst with high surface area shows a highly efficient α alkylation of ketones with primary alcohols.
장점석,김현규,배상원,황동원,지상민,손효창,이재성 한국화학공학회 2007 화학공학의이론과응용 Vol.10 No.2
TiO2-xNy nanoparticle was formed by employing the complex of titanium(III) chloride and ammonium hydroxide as a source of nitrogen. During calcination, an anatase phase of titanium oxide was formed and a part of oxygen in titanium precipitate was successfully substituted by nitrogen originated from strong interacted (or adsorbed) ammonium hydroxide on titanium precipitate. The resulting oxynitride photocatalysts absorb the visible light region, which suggests that the bandgap of TiO2-xNy is narrowed, comparing to that of titanium oxide. Although absorption region is like a small shoulder, TiO2-xNy photocatalyst has the photoactivity to decompose gaseous 2-propanol (IPA) under visible light irradiation. In this work, we investigate the mechanism to form TiO2-xNy and characterize its physical and chemical properties.
장점석,김현규,배상원,지상민,이재성 한국화학공학회 2007 화학공학의이론과응용 Vol.10 No.1
Intercalation of semiconductor oxide with small bandgap into interlayer of layered perovskite is anattractive method to develop photocatalysts active under visible light region. In research, we intercalated iron oxide(Fe2O3) into the interlayer space of layered perovskite (HTiNb(Ta)O5) by a guest exchanged reaction using iron trinuclear acetate -hydroxocation, [Fe3CH3COO)7(OH)(H2O)2] +). We investigated the electronic and local coordination structures of the iron oxide stabilizedbetween the titania-niobate and titania-tantalate layers by X-ray absorption near edge spectroscopy (XANES) and also the oxidation state by X-ray photoelectron spectroscopy (XPS). It was observed that the electronic and local coordination structures of the iron oxide stabilized between the layers of perovskite material were in general similar to those of Fe2O3(Fe(III)) state rather than FeO(Fe(II)). Finally, we investigated the photocatalytic activity of intercalated HTiNb(Ta)O5 layered perovskite under visible light.