Thermal desorption of hydrogen from the. cap alpha. and. beta. modifications of cobalt

Journal Article · Fri Dec 01 04:00:00 EST 1978 · Dokl. Phys. Chem. (Engl. Transl.); (United States)

OSTI ID:5616659

Blagoveshchenskaya, I N; Bubenkova, L V; Popova, N M; Sokol'skii, D V

The results of the investigation of the interaction of hydrogen with ..cap alpha..-cobalt black are presented. The ..cap alpha..-cobalt black was obtained by reducing cobalt formate in a stream of hydrogen at 350/sup 0/C. To remove the hydrogen absorbed the sample was heated to 350/sup 0/C in a stream of argon. The cobalt black prepared in this way had a surface area of 6.6 m/sup 2//g as determined by the low temperature adsorption of krypton and maintained its hexagonal structure on processing in argon to 380/sup 0/C as determined by x-ray analysis. The desorption spectrum of ..cap alpha..-Co black is characterized by four temperature regions of hydrogen evolution. The total amount of desorbed hydrogen was 1.30 x 10/sup 15/ atoms/cm/sup 2/ and the atom ratio H:Me equaled 0.86 based on a cobalt atom surface density of 1.5 x 10/sup 15/ atoms/cm/sup 2/. It is apparent that at common adsorption temperatures (300/sup 0/C) ..cap alpha..-Co chemisorbs four forms of hydrogen while ..beta..-Co, which is formed at higher temperatures (600/sup 0/C, adsorbs three forms of hydrogen. If an almost complete monolayer is achieved on ..cap alpha..-Co the atom ratio equals 0.96, then on ..beta..-Co the ratio is smaller and equals only 0.30. Both the molecular and atomic forms of chemisorbed hydrogen on ..cap alpha..-Co black have higher bonding energies than on ..beta..-Co black. The observed differences of the hydrogen adsorption properties of alpha and beta cobalt black can be attributed to the differences in the lattice structure of the metal. 3 figures, 1 table.

• Research Organization: Inst. of Organic Catalysis and Electrochemistry, Alma-Ata, USSR
• OSTI ID: 5616659
• Journal Information: Dokl. Phys. Chem. (Engl. Transl.); (United States), Journal Name: Dokl. Phys. Chem. (Engl. Transl.); (United States) Vol. 243:4-6; ISSN DKPCA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ARGON
CARBOXYLIC ACID SALTS
CHEMICAL ANALYSIS
CHEMICAL REACTION YIELD
CHEMICAL REACTIONS
COBALT
COMPARATIVE EVALUATIONS
CRYOGENIC FLUIDS
CRYSTAL LATTICES
CRYSTAL STRUCTURE
DESORPTION
ELEMENTS
FLUIDS
FORMATES
HIGH TEMPERATURE
HYDROGEN
METALS
MODIFICATIONS
NONDESTRUCTIVE ANALYSIS
NONMETALS
RARE GASES
SORPTIVE PROPERTIES
SURFACE PROPERTIES
TEMPERATURE DEPENDENCE
TRANSITION ELEMENTS
X-RAY EMISSION ANALYSIS
YIELDS