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Hydrogen adsorption on rhodium

Journal Article · · Sov. Electrochem. (Engl. Transl.); (United States)
OSTI ID:5338711

Measurements of thermal desorption and electron work function were used to investigate the mechanism of hydrogen adsorption from the gas phase on rhodium single-crystal faces and on a polycrystalline rhodium sample at room temperatures over the pressure range from 1.3-10/sup -3/ to 1.3 x 10/sup -5/ Pa. It was found that dipoles oriented with their negative ends toward the gas phase (dipoles of type I) form more rapidly than dipoles having the opposite orientation (dipoles of type II). For formation of the latter, a mechanism is proposed according to which the rate-determining step of the overall process is the transition of reversibly adsorbed hydrogen to dipoles of type II (the spillover), which occurs at surface defects. It was shown that the kinetics of this process with respect to the individual defect obeys an equation which is zeroth order in theta/sub H/ and pressure.

Research Organization:
A. N. Frumkin Institute of Electrochemistry, Moscow (USSR)
OSTI ID:
5338711
Journal Information:
Sov. Electrochem. (Engl. Transl.); (United States), Journal Name: Sov. Electrochem. (Engl. Transl.); (United States) Vol. 23:3; ISSN SOECA
Country of Publication:
United States
Language:
English