Abstract: Hydrogen and oxygen adsorption and their mutual low temperature reaction on iridium surfaces have been studied by thermal desorption and field emission techniques. Oxygen chemisorption proceeds with zero activation energy and the iridium work function increases. No Iow temperature molecular adsorption has been observed. Hydrogen is adsorbed in two dissociated α- and β-forms, differing from each other by their effect on the work function of iridium. The initial value of the isosteric heat of β-hydrogen adsorption is about 23 kcal/mole and it decreases with the increasing coverage to 15 kcal/mole. Preadsorbed oxygen reacts readily with hydrogen in the temperature range 150-200 K, the most active regions being the stepped (321) planes. The least active areas are the atomically rough (012) and (013) planes. The occurrence of the sharp zone boundary supplies the evidence for hydrogen-oxygen reaction in the adsorbed layer. The anisotropy of this reaction zone around the (111) plane has been interpreted in terms of the Localized-Free Electron interplay Model. The explanation of the high activity of iridium surfaces in the low temperature hydrogen oxidation is based on the observed high reactivity of the dissociatively adsorbed forms both of hydrogen and oxygen. The results of the present study are compared with those obtained previously on platinum.

Cite: Gorodetskii V.V. , Sobyanin V.A. , Bulgakov N.N. , Knor Z.
Low Temperature Reaction of Hydrogen with Preadsorbed Oxygen on Iridium Surfaces
Surface Science. 1979. V.82. N1. P.120-138. DOI: 10.1016/0039-6028(79)90323-6 WOS Scopus РИНЦ ANCAN OpenAlex

Dates:

Submitted:	Jul 26, 1978
Accepted:	Oct 25, 1978
Published print:	Mar 2, 1979
Published online:	Sep 5, 2002

Identifiers:

Web of science:	WOS:A1979GM66200009
Scopus:	2-s2.0-0038896726
Elibrary:	31107160
Chemical Abstracts:	1979:157696
Chemical Abstracts (print):	90:157696
OpenAlex:	W2088088881

Citing:

DB	Citing
Web of science	31
Scopus	31
Elibrary	30
OpenAlex	33

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