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Title: Adsorption and photooxidation of CH{sub 3}CN on TiO{sub 2}

Abstract

The adsorption and photooxidation of CH{sub 3}CN chemisorbed on TiO{sub 2} has been investigated using infrared spectroscopy. It was found that CH{sub 3}CN forms an ice layer on TiO{sub 2} at 126 K and above 126 K CH{sub 3}CN diffusion into TiO{sub 2} occurs. At 200 K, the adsorption of CH{sub 3}CN on both isolated Ti-OH groups and on the Ti{sup 4+} Lewis acid site was observed. Under UV irradiation (350 {+-} 50 nm; hv = 3.10--4.13 eV), CH{sub 3}CN was oxidized in the presence of O{sub 2} to form H{sub 2}O, CO{sub 2}, surface CO{sub 3}{sup 2{minus}} and an intermediate partially oxidized isocyanate species, NCO, which was identified by various isotopic experiments. Photooxidation of the CH{sub 3} moiety in adsorbed CH{sub 3}CN occurs more readily than does the CN moiety in CH{sub 3}CN. Lattice oxygen of TiO{sub 2} was found to preferentially form adsorbed NCO, compared to oxygen from adsorbed O{sub 2}. A mechanism of the formation of NCO species was postulated.

Authors:
; ;  [1]
  1. Univ. of Pittsburgh, PA (United States)
Publication Date:
OSTI Identifier:
691305
Resource Type:
Journal Article
Journal Name:
Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical
Additional Journal Information:
Journal Volume: 103; Journal Issue: 33; Other Information: PBD: 19 Aug 1999
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 40 CHEMISTRY; ADSORPTION; PHOTOLYSIS; OXIDATION; PHOTOCHEMICAL OXIDANTS; ACETONITRILE; TITANIUM OXIDES

Citation Formats

Zhuang, J., Rusu, C.N., and Yates, J.T. Jr. Adsorption and photooxidation of CH{sub 3}CN on TiO{sub 2}. United States: N. p., 1999. Web. doi:10.1021/jp991040w.
Zhuang, J., Rusu, C.N., & Yates, J.T. Jr. Adsorption and photooxidation of CH{sub 3}CN on TiO{sub 2}. United States. doi:10.1021/jp991040w.
Zhuang, J., Rusu, C.N., and Yates, J.T. Jr. Thu . "Adsorption and photooxidation of CH{sub 3}CN on TiO{sub 2}". United States. doi:10.1021/jp991040w.
@article{osti_691305,
title = {Adsorption and photooxidation of CH{sub 3}CN on TiO{sub 2}},
author = {Zhuang, J. and Rusu, C.N. and Yates, J.T. Jr.},
abstractNote = {The adsorption and photooxidation of CH{sub 3}CN chemisorbed on TiO{sub 2} has been investigated using infrared spectroscopy. It was found that CH{sub 3}CN forms an ice layer on TiO{sub 2} at 126 K and above 126 K CH{sub 3}CN diffusion into TiO{sub 2} occurs. At 200 K, the adsorption of CH{sub 3}CN on both isolated Ti-OH groups and on the Ti{sup 4+} Lewis acid site was observed. Under UV irradiation (350 {+-} 50 nm; hv = 3.10--4.13 eV), CH{sub 3}CN was oxidized in the presence of O{sub 2} to form H{sub 2}O, CO{sub 2}, surface CO{sub 3}{sup 2{minus}} and an intermediate partially oxidized isocyanate species, NCO, which was identified by various isotopic experiments. Photooxidation of the CH{sub 3} moiety in adsorbed CH{sub 3}CN occurs more readily than does the CN moiety in CH{sub 3}CN. Lattice oxygen of TiO{sub 2} was found to preferentially form adsorbed NCO, compared to oxygen from adsorbed O{sub 2}. A mechanism of the formation of NCO species was postulated.},
doi = {10.1021/jp991040w},
journal = {Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical},
number = 33,
volume = 103,
place = {United States},
year = {1999},
month = {8}
}