Delaminated kaolinites as potential photocatalysts: Tracking degradation of Na-benzenesulfonate test compound adsorbed on the dry surface of kaolinite nanostructures

Péter Szabó, Balázs Zsirka, Dávid Fertig, E. Horváth, Tamás Csizmadia, János Kristóf

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Based on their bandgap values, kaolins can have semiconductive and photocatalytic properties enabling them to use as potential photocatalysts. Kaolinite nanostructures (Knano) and silver-coated kaolinite nanohybrids (Knano(Ag)) were made of ordered (Hinkley Index, HI = 1.4) and disordered (HI = 0.3) kaolins via intercalation/deintercalation. The book-type kaolin built up from tetrahedral(T)-octahedral(O) double layers has very low photocatalytic activity. At the same time the nanostructures made of individual TO layers show photochemical activity in spite of the fact that their bandgap values are comparable to those of the book-type ones. The presence of Ag on the surface significantly reduced the bandgap and shifted the excitation wavelength towards the visible range. This phenomenon supports the supposition that kaolinite has some semiconductive character. This work presents the connection between photocatalytic activity and morphology for the first time. The surface activity of kaolinite nanostructures and their Ag-hybrids was studied through the decomposition of sodium-benzenesulfonate (BS) test compound with attenuated total reflection Fourier transform infrared spectroscopy (FT-IR/ATR). BS decomposition can be detected on the Knano surface but with low efficiency. The presence of silver can significantly improve the mineralization efficiency. No correlation was found between the activity and the quantity of Ti and Fe contaminants and the amount of Ag on the surface. However, the activity could be correlated with the order-dependent morphology (mixture of semi-hexagonal and nanoscroll-type structures), the pore size and with the increase of the surface coverage.

Original languageEnglish
Pages (from-to)37-44
Number of pages8
JournalCatalysis Today
Volume287
DOIs
Publication statusPublished - Jun 1 2017

Fingerprint

Kaolin
Kaolinite
Photocatalysts
Nanostructures
Degradation
Energy gap
Silver
Decomposition
Intercalation
Pore size
Fourier transform infrared spectroscopy
benzenesulfonic acid
Sodium
Impurities
Wavelength

Keywords

  • Ag-nanohybrides
  • FT-IR spectroscopy
  • Kaolinite nanostructures
  • Mineralization
  • Photocatalysis

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)

Cite this

Delaminated kaolinites as potential photocatalysts : Tracking degradation of Na-benzenesulfonate test compound adsorbed on the dry surface of kaolinite nanostructures. / Szabó, Péter; Zsirka, Balázs; Fertig, Dávid; Horváth, E.; Csizmadia, Tamás; Kristóf, János.

In: Catalysis Today, Vol. 287, 01.06.2017, p. 37-44.

Research output: Contribution to journalArticle

@article{040f09f17f944273a2cb244955bcf05c,
title = "Delaminated kaolinites as potential photocatalysts: Tracking degradation of Na-benzenesulfonate test compound adsorbed on the dry surface of kaolinite nanostructures",
abstract = "Based on their bandgap values, kaolins can have semiconductive and photocatalytic properties enabling them to use as potential photocatalysts. Kaolinite nanostructures (Knano) and silver-coated kaolinite nanohybrids (Knano(Ag)) were made of ordered (Hinkley Index, HI = 1.4) and disordered (HI = 0.3) kaolins via intercalation/deintercalation. The book-type kaolin built up from tetrahedral(T)-octahedral(O) double layers has very low photocatalytic activity. At the same time the nanostructures made of individual TO layers show photochemical activity in spite of the fact that their bandgap values are comparable to those of the book-type ones. The presence of Ag on the surface significantly reduced the bandgap and shifted the excitation wavelength towards the visible range. This phenomenon supports the supposition that kaolinite has some semiconductive character. This work presents the connection between photocatalytic activity and morphology for the first time. The surface activity of kaolinite nanostructures and their Ag-hybrids was studied through the decomposition of sodium-benzenesulfonate (BS) test compound with attenuated total reflection Fourier transform infrared spectroscopy (FT-IR/ATR). BS decomposition can be detected on the Knano surface but with low efficiency. The presence of silver can significantly improve the mineralization efficiency. No correlation was found between the activity and the quantity of Ti and Fe contaminants and the amount of Ag on the surface. However, the activity could be correlated with the order-dependent morphology (mixture of semi-hexagonal and nanoscroll-type structures), the pore size and with the increase of the surface coverage.",
keywords = "Ag-nanohybrides, FT-IR spectroscopy, Kaolinite nanostructures, Mineralization, Photocatalysis",
author = "P{\'e}ter Szab{\'o} and Bal{\'a}zs Zsirka and D{\'a}vid Fertig and E. Horv{\'a}th and Tam{\'a}s Csizmadia and J{\'a}nos Krist{\'o}f",
year = "2017",
month = "6",
day = "1",
doi = "10.1016/j.cattod.2017.01.051",
language = "English",
volume = "287",
pages = "37--44",
journal = "Catalysis Today",
issn = "0920-5861",
publisher = "Elsevier",

}

TY - JOUR

T1 - Delaminated kaolinites as potential photocatalysts

T2 - Tracking degradation of Na-benzenesulfonate test compound adsorbed on the dry surface of kaolinite nanostructures

AU - Szabó, Péter

AU - Zsirka, Balázs

AU - Fertig, Dávid

AU - Horváth, E.

AU - Csizmadia, Tamás

AU - Kristóf, János

PY - 2017/6/1

Y1 - 2017/6/1

N2 - Based on their bandgap values, kaolins can have semiconductive and photocatalytic properties enabling them to use as potential photocatalysts. Kaolinite nanostructures (Knano) and silver-coated kaolinite nanohybrids (Knano(Ag)) were made of ordered (Hinkley Index, HI = 1.4) and disordered (HI = 0.3) kaolins via intercalation/deintercalation. The book-type kaolin built up from tetrahedral(T)-octahedral(O) double layers has very low photocatalytic activity. At the same time the nanostructures made of individual TO layers show photochemical activity in spite of the fact that their bandgap values are comparable to those of the book-type ones. The presence of Ag on the surface significantly reduced the bandgap and shifted the excitation wavelength towards the visible range. This phenomenon supports the supposition that kaolinite has some semiconductive character. This work presents the connection between photocatalytic activity and morphology for the first time. The surface activity of kaolinite nanostructures and their Ag-hybrids was studied through the decomposition of sodium-benzenesulfonate (BS) test compound with attenuated total reflection Fourier transform infrared spectroscopy (FT-IR/ATR). BS decomposition can be detected on the Knano surface but with low efficiency. The presence of silver can significantly improve the mineralization efficiency. No correlation was found between the activity and the quantity of Ti and Fe contaminants and the amount of Ag on the surface. However, the activity could be correlated with the order-dependent morphology (mixture of semi-hexagonal and nanoscroll-type structures), the pore size and with the increase of the surface coverage.

AB - Based on their bandgap values, kaolins can have semiconductive and photocatalytic properties enabling them to use as potential photocatalysts. Kaolinite nanostructures (Knano) and silver-coated kaolinite nanohybrids (Knano(Ag)) were made of ordered (Hinkley Index, HI = 1.4) and disordered (HI = 0.3) kaolins via intercalation/deintercalation. The book-type kaolin built up from tetrahedral(T)-octahedral(O) double layers has very low photocatalytic activity. At the same time the nanostructures made of individual TO layers show photochemical activity in spite of the fact that their bandgap values are comparable to those of the book-type ones. The presence of Ag on the surface significantly reduced the bandgap and shifted the excitation wavelength towards the visible range. This phenomenon supports the supposition that kaolinite has some semiconductive character. This work presents the connection between photocatalytic activity and morphology for the first time. The surface activity of kaolinite nanostructures and their Ag-hybrids was studied through the decomposition of sodium-benzenesulfonate (BS) test compound with attenuated total reflection Fourier transform infrared spectroscopy (FT-IR/ATR). BS decomposition can be detected on the Knano surface but with low efficiency. The presence of silver can significantly improve the mineralization efficiency. No correlation was found between the activity and the quantity of Ti and Fe contaminants and the amount of Ag on the surface. However, the activity could be correlated with the order-dependent morphology (mixture of semi-hexagonal and nanoscroll-type structures), the pore size and with the increase of the surface coverage.

KW - Ag-nanohybrides

KW - FT-IR spectroscopy

KW - Kaolinite nanostructures

KW - Mineralization

KW - Photocatalysis

UR - http://www.scopus.com/inward/record.url?scp=85013059608&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85013059608&partnerID=8YFLogxK

U2 - 10.1016/j.cattod.2017.01.051

DO - 10.1016/j.cattod.2017.01.051

M3 - Article

AN - SCOPUS:85013059608

VL - 287

SP - 37

EP - 44

JO - Catalysis Today

JF - Catalysis Today

SN - 0920-5861

ER -