The hydrogenolysis of ethane over Re-Pt(111) and Pt-Re(0001) bimetallic crystal surfaces

Journal Article · Mon May 01 00:00:00 EDT 1989 · Journal of Catalysis; (USA)

DOI:https://doi.org/10.1016/0021-9517(89)90227-3· OSTI ID:6352554

Godbey, D J; Garin, F; Somorjai, G A ^[1]

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1. Univ. of California, Berkeley (USA) Lawrence Berkeley Lab., CA (USA)

Pt-Re bimetallic surfaces were prepared by condensing both Re on the (111) face of Pt and Pt on the (0001) face of Re from the vapor under ultrahigh vacuum. Using a high-pressure microreactor, the hydrogenolysis of ethane was investigated over the small-area catalysts in the temperature range 300-350{degree}C, with pressure of 5-10 Torr ethane and 100-1000 Torr hydrogen. The reaction is structure sensitive on both Pt and Re as indicated by the large increase in the initial rates of reaction observed after the Pt(111) and Re(0001) surfaces were roughened by argon ion bombardment. The Re(0001) surface was two orders of magnitude more active than the Pt(111) surface, yet a bimetallic surface of the stoichiometry Re{sub 2}Pt was found to be the most active surface for ethane hydrogenolysis - about one order of magnitude more active than the Re(0001) surface. Thus the activity of the bimetallic catalyst is not a linear combination of the activities due to the two metallic components. Hydrogen pressure dependence studies show that a bimetallic surface composed of 0.3 monolayer of Re on Pt(111) had an activity close to that of a monometallic Re(0001) surface, yet displayed and hydrogen partial pressure dependence closer to that of a Pt(111) surface. These results suggest that an electronic interaction exists between Pt and Re metals that strongly influence the catalytic hydrogenolysis of ethane. The accumulation of carbonaceous deposits was fairly insensitive to temperature and hydrogen pressure on Re and bimetallic Pt-Re surfaces. However, the accumulation of carbonaceous deposits on monometallic Pt(111) surfaces was highly sensitive to the reaction conditions, and adsorbed on this surface more tenaciously than on bimetallic Pt-Re surfaces. 30 refs.

• DOE Contract Number: AC03-76SF00098
• OSTI ID: 6352554
• Journal Information: Journal of Catalysis; (USA), Vol. 117:1; ISSN 0021-9517
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
ETHANE
DEHYDROGENATION
PLATINUM
CATALYTIC EFFECTS
RHENIUM
BIMETALS
CARBONACEOUS MATERIALS
CATALYSTS
CATALYTIC REFORMING
CHEMICAL PREPARATION
COMPARATIVE EVALUATIONS
CRYSTAL STRUCTURE
DEPOSITION
HIGH TEMPERATURE
HYDROCARBONS
LOW PRESSURE
MEDIUM PRESSURE
PETROLEUM INDUSTRY
PRESSURE DEPENDENCE
SURFACE PROPERTIES
ALKANES
CHEMICAL REACTIONS
ELEMENTS
INDUSTRY
MATERIALS
METALS
ORGANIC COMPOUNDS
PLATINUM METALS
REFORMER PROCESSES
SYNTHESIS
TRANSITION ELEMENTS
020400* - Petroleum- Processing