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Title: Role of coverage in determining adsorbate stability: Phenol reactivity on Rh(111)

Abstract

The reaction of phenol on Rb(111) has been studied by use of temperature programmed reaction and X-ray photoelectron spectroscopies under ultrahigh vacuum. Phenol undergoes competing molecular desorption and O-H bond cleavage to form adsorbed phenoxy below 300 K. Phenoxy quantitatively reacts to form carbon monoxide (400-500 K) and stoichiometric amounts of surface carbon and dihydrogen. O-H bond cleavage of phenol occurs at temperature as low as 120 K, but no C-H bond cleavage occurs until above 350 K. The decomposition kinetics of the adsorbed phenoxy are strongly dependent on its coverage. At low coverage phenoxy decomposes below 400 K to form adsorbed CO which desorbs near 500 K, while at saturation coverage, phenoxy decomposes about 450 K to CO, a large fraction of which is evolved directly into the gas phase at 495 K. Comparison of the reactivity of phenoxy on Rh(111) with previous studies of Mo(110) suggests that the strength of the metal-oxygen bond results in different selectivities on the two surfaces. On Mo(110), all C-O bonds are broken by 450 K leaving an oxygen overlayer on the surface whereas no C-O bond breaking is induced by the Rh(111) surface.

Authors:
;  [1]
  1. Harvard Univ., Cambridge, MA (USA)
Publication Date:
OSTI Identifier:
7197315
Resource Type:
Journal Article
Journal Name:
Journal of Physical Chemistry; (USA)
Additional Journal Information:
Journal Volume: 93:24; Journal ID: ISSN 0022-3654
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CATALYSTS; PHENOLS; REACTIVITY; ADSORBENTS; CARBON MONOXIDE; DATA ANALYSIS; EXPERIMENTAL DATA; MEASURING INSTRUMENTS; MEASURING METHODS; RHODIUM; ULTRAHIGH VACUUM; AROMATICS; CARBON COMPOUNDS; CARBON OXIDES; CHALCOGENIDES; DATA; ELEMENTS; HYDROXY COMPOUNDS; INFORMATION; METALS; NUMERICAL DATA; ORGANIC COMPOUNDS; OXIDES; OXYGEN COMPOUNDS; PLATINUM METALS; TRANSITION ELEMENTS; 400000* - Chemistry; 400201 - Chemical & Physicochemical Properties

Citation Formats

Xu, Xueping, and Friend, C M. Role of coverage in determining adsorbate stability: Phenol reactivity on Rh(111). United States: N. p., 1989. Web. doi:10.1021/j100361a021.
Xu, Xueping, & Friend, C M. Role of coverage in determining adsorbate stability: Phenol reactivity on Rh(111). United States. https://doi.org/10.1021/j100361a021
Xu, Xueping, and Friend, C M. 1989. "Role of coverage in determining adsorbate stability: Phenol reactivity on Rh(111)". United States. https://doi.org/10.1021/j100361a021.
@article{osti_7197315,
title = {Role of coverage in determining adsorbate stability: Phenol reactivity on Rh(111)},
author = {Xu, Xueping and Friend, C M},
abstractNote = {The reaction of phenol on Rb(111) has been studied by use of temperature programmed reaction and X-ray photoelectron spectroscopies under ultrahigh vacuum. Phenol undergoes competing molecular desorption and O-H bond cleavage to form adsorbed phenoxy below 300 K. Phenoxy quantitatively reacts to form carbon monoxide (400-500 K) and stoichiometric amounts of surface carbon and dihydrogen. O-H bond cleavage of phenol occurs at temperature as low as 120 K, but no C-H bond cleavage occurs until above 350 K. The decomposition kinetics of the adsorbed phenoxy are strongly dependent on its coverage. At low coverage phenoxy decomposes below 400 K to form adsorbed CO which desorbs near 500 K, while at saturation coverage, phenoxy decomposes about 450 K to CO, a large fraction of which is evolved directly into the gas phase at 495 K. Comparison of the reactivity of phenoxy on Rh(111) with previous studies of Mo(110) suggests that the strength of the metal-oxygen bond results in different selectivities on the two surfaces. On Mo(110), all C-O bonds are broken by 450 K leaving an oxygen overlayer on the surface whereas no C-O bond breaking is induced by the Rh(111) surface.},
doi = {10.1021/j100361a021},
url = {https://www.osti.gov/biblio/7197315}, journal = {Journal of Physical Chemistry; (USA)},
issn = {0022-3654},
number = ,
volume = 93:24,
place = {United States},
year = {1989},
month = {11}
}