Photocatalytic oxidation of cyclohexane over TiO2: Evidence for a Mars-van krevelen mechanism

Ana R. Almeida; Jacob A. Moulijn; Guido Mul

doi:10.1021/jp107290r

Photocatalytic oxidation of cyclohexane over TiO2: Evidence for a Mars-van krevelen mechanism

Ana R. Almeida, Jacob A. Moulijn, Guido Mul

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Abstract

Cyclohexane photocatalytic oxidation with 18O2 over anatase TiO2 was analyzed by in situ attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, to gain insight in the mechanistic steps of formation of cyclohexanone and deactivating carboxylate species, respectively. Cyclohexane photo-oxidation on TiO2 with increasing concentration of labeled Ti−18OH sites yielded cyclohexanone and surface deactivating species with an isotopic distribution reflecting the concentration of Ti−18OH sites on the surface. This finding suggests that oxygen incorporated in cyclohexanone, as well as in deactivating carbonates and carboxylates, originates from the catalyst surface, rather than from dissolved O2. Cyclohexyl hydroperoxide, observed spectroscopically, is a spectator species, rather than a commonly assumed reaction intermediate. The proposed Mars−van Krevelen cycle is completed by regeneration of surface sites by reaction with 18O2

Original language	English
Pages (from-to)	1330-1338
Number of pages	9
Journal	The Journal of physical chemistry C
Volume	115
Issue number	4
DOIs	https://doi.org/10.1021/jp107290r
Publication status	Published - 2011

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2024 OA procedure

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title = "Photocatalytic oxidation of cyclohexane over TiO2: Evidence for a Mars-van krevelen mechanism",

abstract = "Cyclohexane photocatalytic oxidation with 18O2 over anatase TiO2 was analyzed by in situ attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, to gain insight in the mechanistic steps of formation of cyclohexanone and deactivating carboxylate species, respectively. Cyclohexane photo-oxidation on TiO2 with increasing concentration of labeled Ti−18OH sites yielded cyclohexanone and surface deactivating species with an isotopic distribution reflecting the concentration of Ti−18OH sites on the surface. This finding suggests that oxygen incorporated in cyclohexanone, as well as in deactivating carbonates and carboxylates, originates from the catalyst surface, rather than from dissolved O2. Cyclohexyl hydroperoxide, observed spectroscopically, is a spectator species, rather than a commonly assumed reaction intermediate. The proposed Mars−van Krevelen cycle is completed by regeneration of surface sites by reaction with 18O2",

keywords = "2024 OA procedure",

author = "Almeida, {Ana R.} and Moulijn, {Jacob A.} and Guido Mul",

year = "2011",

doi = "10.1021/jp107290r",

language = "English",

volume = "115",

pages = "1330--1338",

journal = "The Journal of physical chemistry C",

issn = "1932-7447",

publisher = "American Chemical Society",

number = "4",

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TY - JOUR

T1 - Photocatalytic oxidation of cyclohexane over TiO2

T2 - Evidence for a Mars-van krevelen mechanism

AU - Almeida, Ana R.

AU - Moulijn, Jacob A.

AU - Mul, Guido

PY - 2011

Y1 - 2011

N2 - Cyclohexane photocatalytic oxidation with 18O2 over anatase TiO2 was analyzed by in situ attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, to gain insight in the mechanistic steps of formation of cyclohexanone and deactivating carboxylate species, respectively. Cyclohexane photo-oxidation on TiO2 with increasing concentration of labeled Ti−18OH sites yielded cyclohexanone and surface deactivating species with an isotopic distribution reflecting the concentration of Ti−18OH sites on the surface. This finding suggests that oxygen incorporated in cyclohexanone, as well as in deactivating carbonates and carboxylates, originates from the catalyst surface, rather than from dissolved O2. Cyclohexyl hydroperoxide, observed spectroscopically, is a spectator species, rather than a commonly assumed reaction intermediate. The proposed Mars−van Krevelen cycle is completed by regeneration of surface sites by reaction with 18O2

AB - Cyclohexane photocatalytic oxidation with 18O2 over anatase TiO2 was analyzed by in situ attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, to gain insight in the mechanistic steps of formation of cyclohexanone and deactivating carboxylate species, respectively. Cyclohexane photo-oxidation on TiO2 with increasing concentration of labeled Ti−18OH sites yielded cyclohexanone and surface deactivating species with an isotopic distribution reflecting the concentration of Ti−18OH sites on the surface. This finding suggests that oxygen incorporated in cyclohexanone, as well as in deactivating carbonates and carboxylates, originates from the catalyst surface, rather than from dissolved O2. Cyclohexyl hydroperoxide, observed spectroscopically, is a spectator species, rather than a commonly assumed reaction intermediate. The proposed Mars−van Krevelen cycle is completed by regeneration of surface sites by reaction with 18O2

KW - 2024 OA procedure

U2 - 10.1021/jp107290r

DO - 10.1021/jp107290r

M3 - Article

SN - 1932-7447

VL - 115

SP - 1330

EP - 1338

JO - The Journal of physical chemistry C

JF - The Journal of physical chemistry C

IS - 4

ER -

Photocatalytic oxidation of cyclohexane over TiO2: Evidence for a Mars-van krevelen mechanism

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