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Title: New approach to manipulating and characterizing powdered photoadsorbents: NO on Cl-treated Fe{sub 2}O{sub 3}

Abstract

Photon-enhanced catalysis and adsorption offer significant advantages over thermal processes in many environmental protection and cleanup applications. However, up to now relatively little work has focused on improving material performance by chemical surface modification. Here the authors show that powdered Fe{sub 2}O{sub 3} treated with aqueous NH{sub 4}Cl exhibits appreciable activity for the photoadsorption of NO, whereas the pure iron oxide does not. Through the use of a specially designed apparatus for performing temperature-programmed desorption with illuminated powders, the authors demonstrate the existence of a distribution of binding states, only some of which exhibit reversibility. Analytical methods developed recently in this laboratory permit extraction of the sticking probability, desorption order, preexponential factor, and energy distribution for the reversible states. The results suggest nondissociative chemisorption with an average binding energy near 25 kcal/mol. The authors rationalize the unusually low prefactor for desorption (2 x 10{sup 11}s{sup {minus}1}) in terms of a new physical picture invoking adsorbate ionization on a semiconductor surface.

Authors:
;
Publication Date:
Research Org.:
Univ. of Illinois, Urbana, IL (US)
OSTI Identifier:
20000530
Report Number(s):
CONF-9808111-
Journal ID: ISSN 0743-7463; LANGD5
Resource Type:
Journal Article
Journal Name:
Langmuir
Additional Journal Information:
Journal Volume: 15; Journal Issue: 18; Conference: Third international symposium on effects of surface heterogeneity in adsorption and catalysis on solids, Torun (PL), 08/09/1998--08/16/1998; Other Information: PBD: 31 Aug 1999; Journal ID: ISSN 0743-7463
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; IRON OXIDES; SURFACE TREATMENTS; AMMONIUM CHLORIDES; SORPTIVE PROPERTIES; NITRIC OXIDE; ADSORPTION; PHOTOLYSIS

Citation Formats

Blomiley, E.R., and Seebauer, E.G. New approach to manipulating and characterizing powdered photoadsorbents: NO on Cl-treated Fe{sub 2}O{sub 3}. United States: N. p., 1999. Web. doi:10.1021/la9813329.
Blomiley, E.R., & Seebauer, E.G. New approach to manipulating and characterizing powdered photoadsorbents: NO on Cl-treated Fe{sub 2}O{sub 3}. United States. doi:10.1021/la9813329.
Blomiley, E.R., and Seebauer, E.G. Tue . "New approach to manipulating and characterizing powdered photoadsorbents: NO on Cl-treated Fe{sub 2}O{sub 3}". United States. doi:10.1021/la9813329.
@article{osti_20000530,
title = {New approach to manipulating and characterizing powdered photoadsorbents: NO on Cl-treated Fe{sub 2}O{sub 3}},
author = {Blomiley, E.R. and Seebauer, E.G.},
abstractNote = {Photon-enhanced catalysis and adsorption offer significant advantages over thermal processes in many environmental protection and cleanup applications. However, up to now relatively little work has focused on improving material performance by chemical surface modification. Here the authors show that powdered Fe{sub 2}O{sub 3} treated with aqueous NH{sub 4}Cl exhibits appreciable activity for the photoadsorption of NO, whereas the pure iron oxide does not. Through the use of a specially designed apparatus for performing temperature-programmed desorption with illuminated powders, the authors demonstrate the existence of a distribution of binding states, only some of which exhibit reversibility. Analytical methods developed recently in this laboratory permit extraction of the sticking probability, desorption order, preexponential factor, and energy distribution for the reversible states. The results suggest nondissociative chemisorption with an average binding energy near 25 kcal/mol. The authors rationalize the unusually low prefactor for desorption (2 x 10{sup 11}s{sup {minus}1}) in terms of a new physical picture invoking adsorbate ionization on a semiconductor surface.},
doi = {10.1021/la9813329},
journal = {Langmuir},
issn = {0743-7463},
number = 18,
volume = 15,
place = {United States},
year = {1999},
month = {8}
}