Mossbauer Study of the Kinetics of Fe3+ Photoreduction on TiO2 Semiconductor Powders

J. D. Brown; D. L. Williamson; A. J. Nozik

doi:10.1021/j100260a025

Mossbauer Study of the Kinetics of Fe3+ Photoreduction on TiO2 Semiconductor Powders

J. D. Brown, D. L. Williamson, A. J. Nozik

Chemistry and Nanoscience

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Abstract

The kinetics of the photoreduction of Fe³⁺ to Fe²⁺ via illuminated TiO₂ particles suspended in ferric chloride electrolyte has been studied by ⁵⁷Fe Mössbauer spectroscopy. The semiconductor powder-liquid electrolyte slurry was quench-frozen after specific illumination periods to generate samples amenable to Mössbauer spectroscopy. The rates and equilibrium conversion of Fe³⁺ reduction were obtained for five TiO₂ particle-electrolyte systems: (1) intrinsic anatase powder; (2) intrinsic rutile powder; (3) intrinsic anatase powder with a facile hole acceptor added to the electrolyte; (4) reduced, n-type anatase; and (5) platinized, n-type anatase powder. A simple kinetic model, based on competition between the forward reduction of Fe³⁺ and the back oxidation of Fe²⁺, and controlled by semiconductor band/redox couple energetics, is able to account for the observed differences in Fe³⁺ photoreduction for the five systems.

Original language	American English
Pages (from-to)	3076-3080
Number of pages	5
Journal	Journal of Physical Chemistry
Volume	89
Issue number	14
DOIs	https://doi.org/10.1021/j100260a025 https://doi.org/10.1021/j100260a025
State	Published - 1985

Bibliographical note

Work performed by Department of Physics, Colorado School of Mines, Golden, Colorado, and Solar Energy Research Institute, Golden, Colorado

NREL Publication Number

ACNR/JA-212-6508

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title = "Mossbauer Study of the Kinetics of Fe3+ Photoreduction on TiO2 Semiconductor Powders",

abstract = "The kinetics of the photoreduction of Fe3+ to Fe2+ via illuminated TiO2 particles suspended in ferric chloride electrolyte has been studied by 57Fe M{\"o}ssbauer spectroscopy. The semiconductor powder-liquid electrolyte slurry was quench-frozen after specific illumination periods to generate samples amenable to M{\"o}ssbauer spectroscopy. The rates and equilibrium conversion of Fe3+ reduction were obtained for five TiO2 particle-electrolyte systems: (1) intrinsic anatase powder; (2) intrinsic rutile powder; (3) intrinsic anatase powder with a facile hole acceptor added to the electrolyte; (4) reduced, n-type anatase; and (5) platinized, n-type anatase powder. A simple kinetic model, based on competition between the forward reduction of Fe3+ and the back oxidation of Fe2+, and controlled by semiconductor band/redox couple energetics, is able to account for the observed differences in Fe3+ photoreduction for the five systems.",

author = "Brown, {J. D.} and Williamson, {D. L.} and Nozik, {A. J.}",

note = "Work performed by Department of Physics, Colorado School of Mines, Golden, Colorado, and Solar Energy Research Institute, Golden, Colorado",

year = "1985",

doi = "10.1021/j100260a025",

language = "American English",

volume = "89",

pages = "3076--3080",

journal = "Journal of Physical Chemistry",

issn = "0022-3654",

publisher = "American Chemical Society",

number = "14",

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T1 - Mossbauer Study of the Kinetics of Fe3+ Photoreduction on TiO2 Semiconductor Powders

AU - Brown, J. D.

AU - Williamson, D. L.

AU - Nozik, A. J.

N1 - Work performed by Department of Physics, Colorado School of Mines, Golden, Colorado, and Solar Energy Research Institute, Golden, Colorado

PY - 1985

Y1 - 1985

N2 - The kinetics of the photoreduction of Fe3+ to Fe2+ via illuminated TiO2 particles suspended in ferric chloride electrolyte has been studied by 57Fe Mössbauer spectroscopy. The semiconductor powder-liquid electrolyte slurry was quench-frozen after specific illumination periods to generate samples amenable to Mössbauer spectroscopy. The rates and equilibrium conversion of Fe3+ reduction were obtained for five TiO2 particle-electrolyte systems: (1) intrinsic anatase powder; (2) intrinsic rutile powder; (3) intrinsic anatase powder with a facile hole acceptor added to the electrolyte; (4) reduced, n-type anatase; and (5) platinized, n-type anatase powder. A simple kinetic model, based on competition between the forward reduction of Fe3+ and the back oxidation of Fe2+, and controlled by semiconductor band/redox couple energetics, is able to account for the observed differences in Fe3+ photoreduction for the five systems.

AB - The kinetics of the photoreduction of Fe3+ to Fe2+ via illuminated TiO2 particles suspended in ferric chloride electrolyte has been studied by 57Fe Mössbauer spectroscopy. The semiconductor powder-liquid electrolyte slurry was quench-frozen after specific illumination periods to generate samples amenable to Mössbauer spectroscopy. The rates and equilibrium conversion of Fe3+ reduction were obtained for five TiO2 particle-electrolyte systems: (1) intrinsic anatase powder; (2) intrinsic rutile powder; (3) intrinsic anatase powder with a facile hole acceptor added to the electrolyte; (4) reduced, n-type anatase; and (5) platinized, n-type anatase powder. A simple kinetic model, based on competition between the forward reduction of Fe3+ and the back oxidation of Fe2+, and controlled by semiconductor band/redox couple energetics, is able to account for the observed differences in Fe3+ photoreduction for the five systems.

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U2 - 10.1021/j100260a025

DO - 10.1021/j100260a025

M3 - Article

AN - SCOPUS:33845378281

SN - 0022-3654

VL - 89

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EP - 3080

JO - Journal of Physical Chemistry

JF - Journal of Physical Chemistry

IS - 14

ER -

Mossbauer Study of the Kinetics of Fe3+ Photoreduction on TiO2 Semiconductor Powders

Abstract

Bibliographical note

NREL Publication Number

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