The influence of the local structure of Fe(III) on the photocatalytic activity of doped TiO2 photocatalysts-An EXAFS, XPS and Mössbauer spectroscopic study

Éva G. Bajnóczi, Nándor Balázs, K. Mogyorósi, Dávid F. Srankó, Zsolt Pap, Zoltán Ambrus, Sophie E. Canton, Katarina Norén, E. Kuzmann, A. Vértes, Z. Homonnay, A. Oszkó, I. Pálinkó, P. Sipos

Research output: Contribution to journalArticle

44 Citations (Scopus)

Abstract

Fe(III)-doped TiO2 based heterogeneous photocatalysts were prepared by the sol-gel technique (S samples) or flame hydrolysis (F samples). In photocatalytic phenol decomposition, the undoped F-sample performed much better, than the undoped S one. However, for the S samples, photocatalytic activity first increased with the increasing Fe(III) concentration, and then passed through a maximum, while Fe(III)-doping in F samples significantly decreased it, even at the smallest dopant level. Since the same dopant caused opposite photocatalytic effects in the two series, their structure was systematically compared to identify the underlying chemical and/or physical reasons. The photocatalysts were first characterized by AAS, DRS, XRD and TEM methods and it has been shown that the differences in the photocatalytic activity cannot be explained by the minor variations in the bulk structural properties of TiO2.Mössbauer and XP spectroscopic measurements performed on representative samples qualitatively proved that the local structure of Fe(III) is different in the two series. To quantify these effects, Fe-K edge X-ray absorption measurements were performed. From the pre-edge and XANES region it was learnt that Fe(III) was present in a distorted octahedral environment in both series, however, the extent of distortion is much more significant within the S than within the F one. Information obtained from the EXAFS region indicated that the structure of Fe2O3 was much more ordered in the F-series then in the S one and vacancies were more abundant in the S than in the F series. Moreover, the geometry around Fe(III) systematically varied within the S-series, which could explain, why photocatalytic activity passed through a maximum with the increasing Fe(III) concentration in these samples.

Original languageEnglish
Pages (from-to)232-239
Number of pages8
JournalApplied Catalysis B: Environmental
Volume103
Issue number1-2
DOIs
Publication statusPublished - Mar 14 2011

Fingerprint

Photocatalysts
X-ray spectroscopy
X ray photoelectron spectroscopy
Doping (additives)
phenol
transmission electron microscopy
hydrolysis
gel
X-ray diffraction
X ray absorption
decomposition
Phenol
geometry
Phenols
Vacancies
Sol-gels
Structural properties
Hydrolysis
Transmission electron microscopy
Decomposition

Keywords

  • EXAFS
  • Fe(III) doping
  • Local structure
  • Mössbauer
  • Photocatalysis
  • TiO2
  • XPS

ASJC Scopus subject areas

  • Catalysis
  • Process Chemistry and Technology
  • Environmental Science(all)

Cite this

The influence of the local structure of Fe(III) on the photocatalytic activity of doped TiO2 photocatalysts-An EXAFS, XPS and Mössbauer spectroscopic study. / Bajnóczi, Éva G.; Balázs, Nándor; Mogyorósi, K.; Srankó, Dávid F.; Pap, Zsolt; Ambrus, Zoltán; Canton, Sophie E.; Norén, Katarina; Kuzmann, E.; Vértes, A.; Homonnay, Z.; Oszkó, A.; Pálinkó, I.; Sipos, P.

In: Applied Catalysis B: Environmental, Vol. 103, No. 1-2, 14.03.2011, p. 232-239.

Research output: Contribution to journalArticle

@article{68c4e92155b341b2b89dc742e4db72e8,
title = "The influence of the local structure of Fe(III) on the photocatalytic activity of doped TiO2 photocatalysts-An EXAFS, XPS and M{\"o}ssbauer spectroscopic study",
abstract = "Fe(III)-doped TiO2 based heterogeneous photocatalysts were prepared by the sol-gel technique (S samples) or flame hydrolysis (F samples). In photocatalytic phenol decomposition, the undoped F-sample performed much better, than the undoped S one. However, for the S samples, photocatalytic activity first increased with the increasing Fe(III) concentration, and then passed through a maximum, while Fe(III)-doping in F samples significantly decreased it, even at the smallest dopant level. Since the same dopant caused opposite photocatalytic effects in the two series, their structure was systematically compared to identify the underlying chemical and/or physical reasons. The photocatalysts were first characterized by AAS, DRS, XRD and TEM methods and it has been shown that the differences in the photocatalytic activity cannot be explained by the minor variations in the bulk structural properties of TiO2.M{\"o}ssbauer and XP spectroscopic measurements performed on representative samples qualitatively proved that the local structure of Fe(III) is different in the two series. To quantify these effects, Fe-K edge X-ray absorption measurements were performed. From the pre-edge and XANES region it was learnt that Fe(III) was present in a distorted octahedral environment in both series, however, the extent of distortion is much more significant within the S than within the F one. Information obtained from the EXAFS region indicated that the structure of Fe2O3 was much more ordered in the F-series then in the S one and vacancies were more abundant in the S than in the F series. Moreover, the geometry around Fe(III) systematically varied within the S-series, which could explain, why photocatalytic activity passed through a maximum with the increasing Fe(III) concentration in these samples.",
keywords = "EXAFS, Fe(III) doping, Local structure, M{\"o}ssbauer, Photocatalysis, TiO2, XPS",
author = "Bajn{\'o}czi, {{\'E}va G.} and N{\'a}ndor Bal{\'a}zs and K. Mogyor{\'o}si and Srank{\'o}, {D{\'a}vid F.} and Zsolt Pap and Zolt{\'a}n Ambrus and Canton, {Sophie E.} and Katarina Nor{\'e}n and E. Kuzmann and A. V{\'e}rtes and Z. Homonnay and A. Oszk{\'o} and I. P{\'a}link{\'o} and P. Sipos",
year = "2011",
month = "3",
day = "14",
doi = "10.1016/j.apcatb.2011.01.033",
language = "English",
volume = "103",
pages = "232--239",
journal = "Applied Catalysis B: Environmental",
issn = "0926-3373",
publisher = "Elsevier",
number = "1-2",

}

TY - JOUR

T1 - The influence of the local structure of Fe(III) on the photocatalytic activity of doped TiO2 photocatalysts-An EXAFS, XPS and Mössbauer spectroscopic study

AU - Bajnóczi, Éva G.

AU - Balázs, Nándor

AU - Mogyorósi, K.

AU - Srankó, Dávid F.

AU - Pap, Zsolt

AU - Ambrus, Zoltán

AU - Canton, Sophie E.

AU - Norén, Katarina

AU - Kuzmann, E.

AU - Vértes, A.

AU - Homonnay, Z.

AU - Oszkó, A.

AU - Pálinkó, I.

AU - Sipos, P.

PY - 2011/3/14

Y1 - 2011/3/14

N2 - Fe(III)-doped TiO2 based heterogeneous photocatalysts were prepared by the sol-gel technique (S samples) or flame hydrolysis (F samples). In photocatalytic phenol decomposition, the undoped F-sample performed much better, than the undoped S one. However, for the S samples, photocatalytic activity first increased with the increasing Fe(III) concentration, and then passed through a maximum, while Fe(III)-doping in F samples significantly decreased it, even at the smallest dopant level. Since the same dopant caused opposite photocatalytic effects in the two series, their structure was systematically compared to identify the underlying chemical and/or physical reasons. The photocatalysts were first characterized by AAS, DRS, XRD and TEM methods and it has been shown that the differences in the photocatalytic activity cannot be explained by the minor variations in the bulk structural properties of TiO2.Mössbauer and XP spectroscopic measurements performed on representative samples qualitatively proved that the local structure of Fe(III) is different in the two series. To quantify these effects, Fe-K edge X-ray absorption measurements were performed. From the pre-edge and XANES region it was learnt that Fe(III) was present in a distorted octahedral environment in both series, however, the extent of distortion is much more significant within the S than within the F one. Information obtained from the EXAFS region indicated that the structure of Fe2O3 was much more ordered in the F-series then in the S one and vacancies were more abundant in the S than in the F series. Moreover, the geometry around Fe(III) systematically varied within the S-series, which could explain, why photocatalytic activity passed through a maximum with the increasing Fe(III) concentration in these samples.

AB - Fe(III)-doped TiO2 based heterogeneous photocatalysts were prepared by the sol-gel technique (S samples) or flame hydrolysis (F samples). In photocatalytic phenol decomposition, the undoped F-sample performed much better, than the undoped S one. However, for the S samples, photocatalytic activity first increased with the increasing Fe(III) concentration, and then passed through a maximum, while Fe(III)-doping in F samples significantly decreased it, even at the smallest dopant level. Since the same dopant caused opposite photocatalytic effects in the two series, their structure was systematically compared to identify the underlying chemical and/or physical reasons. The photocatalysts were first characterized by AAS, DRS, XRD and TEM methods and it has been shown that the differences in the photocatalytic activity cannot be explained by the minor variations in the bulk structural properties of TiO2.Mössbauer and XP spectroscopic measurements performed on representative samples qualitatively proved that the local structure of Fe(III) is different in the two series. To quantify these effects, Fe-K edge X-ray absorption measurements were performed. From the pre-edge and XANES region it was learnt that Fe(III) was present in a distorted octahedral environment in both series, however, the extent of distortion is much more significant within the S than within the F one. Information obtained from the EXAFS region indicated that the structure of Fe2O3 was much more ordered in the F-series then in the S one and vacancies were more abundant in the S than in the F series. Moreover, the geometry around Fe(III) systematically varied within the S-series, which could explain, why photocatalytic activity passed through a maximum with the increasing Fe(III) concentration in these samples.

KW - EXAFS

KW - Fe(III) doping

KW - Local structure

KW - Mössbauer

KW - Photocatalysis

KW - TiO2

KW - XPS

UR - http://www.scopus.com/inward/record.url?scp=79951942564&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=79951942564&partnerID=8YFLogxK

U2 - 10.1016/j.apcatb.2011.01.033

DO - 10.1016/j.apcatb.2011.01.033

M3 - Article

AN - SCOPUS:79951942564

VL - 103

SP - 232

EP - 239

JO - Applied Catalysis B: Environmental

JF - Applied Catalysis B: Environmental

SN - 0926-3373

IS - 1-2

ER -