Dynamics of dissociative adsorption of hydrogen on Ni(100)

Journal Article · Thu Dec 05 04:00:00 EST 1985 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100271a014· OSTI ID:5897484

Hamza, A V; Madix, R J

Nearly monoenergetic beams of hydrogen and deuterium were used to determine dissociative sticking probabilities for H/sub 2/ and D/sub 2/ on Ni(100) at various energies. Variation of the surface temperature between 90 and 300 K had no effect on the dissociative sticking probability of H/sub 2/ at 3.6 and 5.8 kJ/mol incident beam energy, indicating a direct mechanism of dissociation. A four fold increase in the initial dissociative sticking probability for H/sub 2/ from 0.2 to 0.8 was observed by increasing the translational kinetic energy from 0.7 to 7.0 kJ/mol. The initial dissociative sticking probability for D/sub 2/ was slightly lower, increasing from 0.15 to 0.75 with increasing translational kinetic energy from 1.3 to 10.5 kJ/mol. The form of the increase with kinetic energy was explained by tunnelling through a low activation barrier, accounting as well for the high dissociation probability at low kinetic energies. The dissociative sticking probability decreased with hydrogen or deuterium adatom coverage at all energies. The decline in sticking probability with hydrogen coverage was fit to a s(theta) = s/sub 0/(1 - a theta)/sup n/ functional form. From this relationship it was deduced that hydrogen adatoms block only single sites and that four vacant sites are needed for dissociation. The dissociative sticking probability for H/sub 2/ declined precipitously from 0.77 to 0.16 with oxygen adatom coverage from 0 to 5% of a monolayer at a translational energy of 9.6 kJ.mol. 36 references, 8 figures.

• Research Organization: Stanford Univ., CA
• OSTI ID: 5897484
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 89:25; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

08 HYDROGEN
080201 -- Hydrogen-- Chemisorption Storage
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ADSORPTION
ANGULAR DISTRIBUTION
CATALYSIS
CATALYTIC EFFECTS
DATA
DEUTERIUM
DISTRIBUTION
ELEMENTS
ENERGY
EXPERIMENTAL DATA
HYDROGEN
HYDROGEN ISOTOPES
INFORMATION
ISOTOPES
KINETIC ENERGY
LIGHT NUCLEI
LOW TEMPERATURE
MEDIUM TEMPERATURE
METALS
MILLER INDICES
NICKEL
NONMETALS
NUCLEI
NUMERICAL DATA
ODD-ODD NUCLEI
SORPTION
STABLE ISOTOPES
SURFACE PROPERTIES
TRANSITION ELEMENTS