Dispersion of nickel particles supported on alumina and silica in oxygen and hydrogen

Journal Article · Tue May 01 04:00:00 EDT 1984 · J. Catal.; (United States)

DOI:https://doi.org/10.1016/0021-9517(84)90173-8· OSTI ID:7076532

Nakayama, T; Arai, M; Nishiyama, Y

A transmission electron microscopic study was made to examine the behavior of Ni particles supported on amorphous Al/sub 2/O/sub 3/ and SiO/sub 2/ by thermal treatment in H/sub 2/ and O/sub 2/ atmospheres at 60 torr. The sintering during heating in H/sub 2/ at 600/sup 0/C proceeded by particle migration for Ni/Al/sub 2/O/sub 3/ but by atomic migration for Ni/SiO/sub 2/. The rate of increase in the average particle size in H/sub 2/ at 600/sup 0/C was comparable to that under vacuum at the same temperature. Annular or horseshoe-shaped NiO particles spreading over the supports were formed by O/sub 2/-treatment at certain temperatures which were dependent on the support material. The formation of pitted particles was completed in a rather short period of time. By repeated heating in O/sub 2/ and in H/sub 2/ at 600/sup 0/C, the particles reversibly changed their shape at the same positions. However, redispersion, the splitting of particles, occured at other sets of treating temperatures, typically oxidation at 600/sup 0/C and reduction at 400/sup 0/C. The treatment temperatures at which redispersion was observed differed between the two supports. The effect of the support is discussed in terms of particle-support interaction including the formation of a metal-support complex.

• Research Organization: Tohoku Univ., Sendai, Japan
• OSTI ID: 7076532
• Journal Information: J. Catal.; (United States), Journal Name: J. Catal.; (United States) Vol. 87:1; ISSN JCTLA
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020500* -- Petroleum-- Products & By-Products
CATALYST SUPPORTS
CATALYSTS
ELEMENTS
HEAT TREATMENTS
HIGH TEMPERATURE
HYDROGEN
LOW PRESSURE
METALS
NICKEL
NONMETALS
OXYGEN
TRANSITION ELEMENTS