Titanium dioxide surface modified with both palladium and fluoride as an efficient photocatalyst for the degradation of urea

Hyoung il Kim, Kitae Kim, Soona Park, Wooyul Kim, Seungdo Kim, Jungwon Kim

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

TiO2 surface modified with both Pd nanoparticles and fluorides (F-TiO2/Pd) was prepared and applied as a photocatalyst in the degradation of urea. Various surface analysis techniques, including X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, and energy-dispersive X-ray spectroscopy, were used to verify the coexistence of Pd nanoparticles and fluorides on the surface of TiO2 in F-TiO2/Pd. F-TiO2/Pd showed a higher photocatalytic activity than those of bare TiO2 and single-component-modified TiO2 photocatalysts such as fluorinated TiO2 (F-TiO2) and Pd-loaded TiO2 (Pd/TiO2). The higher urea degradation efficiency of F-TiO2/Pd is ascribed to the enhanced production of hydroxyl radicals ([rad]OH) by the synergistic action of the surface Pd and fluoride. Pd nanoparticles and fluorides facilitate the transfer of valence band holes (hvb +) and their reaction with water molecules, respectively, synergistically enhancing the production of [rad]OH. The photocatalytic activity of F-TiO2/Pd for the degradation of urea increased upon increasing the fraction of the fluorinated TiO2 surface, which is higher at higher fluoride concentrations and lower pH. Although Pt/TiO2 showed higher photocatalytic activity for the degradation of urea than those of Pd/TiO2 and Au/TiO2, the strong positive effect of fluoride complexation was only exhibited by Pd/TiO2 (a slight positive effect and a negative effect were observed for Au/TiO2 and Pt/TiO2, respectively). As a result, the degradation of urea proceeded more rapidly in a UV-irradiated suspension of F-TiO2/Pd than when any of other photocatalysts (i.e., bare TiO2, Pd/TiO2, F-TiO2, Au/TiO2, F-TiO2/Au, Pt/TiO2, and F-TiO2/Pt) were used under the same conditions. The first-order degradation rate constants (k) of urea depending on the type of TiO2 were as follows: 0.097 h−1 for bare TiO2, 0.158 h−1 for Pd/TiO2, 0.151 h−1 for F-TiO2, 0.351 h−1 for F-TiO2/Pd, 0.173 h−1 for Au/TiO2, 0.223 h−1 for F-TiO2/Au, 0.240 h−1 for Pt/TiO2, and 0.165 h−1 for F-TiO2/Pt, respectively. In addition, F-TiO2/Pd proved to be stable in repeated urea degradation cycles.

Original languageEnglish
Pages (from-to)580-587
Number of pages8
JournalSeparation and Purification Technology
Volume209
DOIs
Publication statusPublished - 2019 Jan 31

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Palladium
Photocatalysts
Fluorides
Urea
Titanium dioxide
Degradation
Nanoparticles
Surface analysis
High resolution transmission electron microscopy
Valence bands
titanium dioxide
Complexation
Hydroxyl Radical
Rate constants
Suspensions
X ray photoelectron spectroscopy
Molecules
Water

All Science Journal Classification (ASJC) codes

  • Analytical Chemistry
  • Filtration and Separation

Cite this

@article{fe4c1d60d76b4ba2962df1b3a9ec0c96,
title = "Titanium dioxide surface modified with both palladium and fluoride as an efficient photocatalyst for the degradation of urea",
abstract = "TiO2 surface modified with both Pd nanoparticles and fluorides (F-TiO2/Pd) was prepared and applied as a photocatalyst in the degradation of urea. Various surface analysis techniques, including X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, and energy-dispersive X-ray spectroscopy, were used to verify the coexistence of Pd nanoparticles and fluorides on the surface of TiO2 in F-TiO2/Pd. F-TiO2/Pd showed a higher photocatalytic activity than those of bare TiO2 and single-component-modified TiO2 photocatalysts such as fluorinated TiO2 (F-TiO2) and Pd-loaded TiO2 (Pd/TiO2). The higher urea degradation efficiency of F-TiO2/Pd is ascribed to the enhanced production of hydroxyl radicals ([rad]OH) by the synergistic action of the surface Pd and fluoride. Pd nanoparticles and fluorides facilitate the transfer of valence band holes (hvb +) and their reaction with water molecules, respectively, synergistically enhancing the production of [rad]OH. The photocatalytic activity of F-TiO2/Pd for the degradation of urea increased upon increasing the fraction of the fluorinated TiO2 surface, which is higher at higher fluoride concentrations and lower pH. Although Pt/TiO2 showed higher photocatalytic activity for the degradation of urea than those of Pd/TiO2 and Au/TiO2, the strong positive effect of fluoride complexation was only exhibited by Pd/TiO2 (a slight positive effect and a negative effect were observed for Au/TiO2 and Pt/TiO2, respectively). As a result, the degradation of urea proceeded more rapidly in a UV-irradiated suspension of F-TiO2/Pd than when any of other photocatalysts (i.e., bare TiO2, Pd/TiO2, F-TiO2, Au/TiO2, F-TiO2/Au, Pt/TiO2, and F-TiO2/Pt) were used under the same conditions. The first-order degradation rate constants (k) of urea depending on the type of TiO2 were as follows: 0.097 h−1 for bare TiO2, 0.158 h−1 for Pd/TiO2, 0.151 h−1 for F-TiO2, 0.351 h−1 for F-TiO2/Pd, 0.173 h−1 for Au/TiO2, 0.223 h−1 for F-TiO2/Au, 0.240 h−1 for Pt/TiO2, and 0.165 h−1 for F-TiO2/Pt, respectively. In addition, F-TiO2/Pd proved to be stable in repeated urea degradation cycles.",
author = "Kim, {Hyoung il} and Kitae Kim and Soona Park and Wooyul Kim and Seungdo Kim and Jungwon Kim",
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Titanium dioxide surface modified with both palladium and fluoride as an efficient photocatalyst for the degradation of urea. / Kim, Hyoung il; Kim, Kitae; Park, Soona; Kim, Wooyul; Kim, Seungdo; Kim, Jungwon.

In: Separation and Purification Technology, Vol. 209, 31.01.2019, p. 580-587.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Titanium dioxide surface modified with both palladium and fluoride as an efficient photocatalyst for the degradation of urea

AU - Kim, Hyoung il

AU - Kim, Kitae

AU - Park, Soona

AU - Kim, Wooyul

AU - Kim, Seungdo

AU - Kim, Jungwon

PY - 2019/1/31

Y1 - 2019/1/31

N2 - TiO2 surface modified with both Pd nanoparticles and fluorides (F-TiO2/Pd) was prepared and applied as a photocatalyst in the degradation of urea. Various surface analysis techniques, including X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, and energy-dispersive X-ray spectroscopy, were used to verify the coexistence of Pd nanoparticles and fluorides on the surface of TiO2 in F-TiO2/Pd. F-TiO2/Pd showed a higher photocatalytic activity than those of bare TiO2 and single-component-modified TiO2 photocatalysts such as fluorinated TiO2 (F-TiO2) and Pd-loaded TiO2 (Pd/TiO2). The higher urea degradation efficiency of F-TiO2/Pd is ascribed to the enhanced production of hydroxyl radicals ([rad]OH) by the synergistic action of the surface Pd and fluoride. Pd nanoparticles and fluorides facilitate the transfer of valence band holes (hvb +) and their reaction with water molecules, respectively, synergistically enhancing the production of [rad]OH. The photocatalytic activity of F-TiO2/Pd for the degradation of urea increased upon increasing the fraction of the fluorinated TiO2 surface, which is higher at higher fluoride concentrations and lower pH. Although Pt/TiO2 showed higher photocatalytic activity for the degradation of urea than those of Pd/TiO2 and Au/TiO2, the strong positive effect of fluoride complexation was only exhibited by Pd/TiO2 (a slight positive effect and a negative effect were observed for Au/TiO2 and Pt/TiO2, respectively). As a result, the degradation of urea proceeded more rapidly in a UV-irradiated suspension of F-TiO2/Pd than when any of other photocatalysts (i.e., bare TiO2, Pd/TiO2, F-TiO2, Au/TiO2, F-TiO2/Au, Pt/TiO2, and F-TiO2/Pt) were used under the same conditions. The first-order degradation rate constants (k) of urea depending on the type of TiO2 were as follows: 0.097 h−1 for bare TiO2, 0.158 h−1 for Pd/TiO2, 0.151 h−1 for F-TiO2, 0.351 h−1 for F-TiO2/Pd, 0.173 h−1 for Au/TiO2, 0.223 h−1 for F-TiO2/Au, 0.240 h−1 for Pt/TiO2, and 0.165 h−1 for F-TiO2/Pt, respectively. In addition, F-TiO2/Pd proved to be stable in repeated urea degradation cycles.

AB - TiO2 surface modified with both Pd nanoparticles and fluorides (F-TiO2/Pd) was prepared and applied as a photocatalyst in the degradation of urea. Various surface analysis techniques, including X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, and energy-dispersive X-ray spectroscopy, were used to verify the coexistence of Pd nanoparticles and fluorides on the surface of TiO2 in F-TiO2/Pd. F-TiO2/Pd showed a higher photocatalytic activity than those of bare TiO2 and single-component-modified TiO2 photocatalysts such as fluorinated TiO2 (F-TiO2) and Pd-loaded TiO2 (Pd/TiO2). The higher urea degradation efficiency of F-TiO2/Pd is ascribed to the enhanced production of hydroxyl radicals ([rad]OH) by the synergistic action of the surface Pd and fluoride. Pd nanoparticles and fluorides facilitate the transfer of valence band holes (hvb +) and their reaction with water molecules, respectively, synergistically enhancing the production of [rad]OH. The photocatalytic activity of F-TiO2/Pd for the degradation of urea increased upon increasing the fraction of the fluorinated TiO2 surface, which is higher at higher fluoride concentrations and lower pH. Although Pt/TiO2 showed higher photocatalytic activity for the degradation of urea than those of Pd/TiO2 and Au/TiO2, the strong positive effect of fluoride complexation was only exhibited by Pd/TiO2 (a slight positive effect and a negative effect were observed for Au/TiO2 and Pt/TiO2, respectively). As a result, the degradation of urea proceeded more rapidly in a UV-irradiated suspension of F-TiO2/Pd than when any of other photocatalysts (i.e., bare TiO2, Pd/TiO2, F-TiO2, Au/TiO2, F-TiO2/Au, Pt/TiO2, and F-TiO2/Pt) were used under the same conditions. The first-order degradation rate constants (k) of urea depending on the type of TiO2 were as follows: 0.097 h−1 for bare TiO2, 0.158 h−1 for Pd/TiO2, 0.151 h−1 for F-TiO2, 0.351 h−1 for F-TiO2/Pd, 0.173 h−1 for Au/TiO2, 0.223 h−1 for F-TiO2/Au, 0.240 h−1 for Pt/TiO2, and 0.165 h−1 for F-TiO2/Pt, respectively. In addition, F-TiO2/Pd proved to be stable in repeated urea degradation cycles.

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