The effect of potassium and tin on the hydrogenation of Ethyleneand Dehydrogenation of Cyclohexane over Pt(111)

Journal Article · Thu Oct 09 04:00:00 EDT 1997 · Journal of Catalysis

OSTI ID:900637

Park, Yong-Ki; Ribeiro, Fabio H; Somorjai, Gabor A

Stable ordered structures of Sn on Pt (111) (maximumcoverage of 0.33 monolayers) were used as model catalysts to test theeffect of tin and potassium on the hydrogenation of ethylene at 300 K anddehydrogenation of cyclohexane at 573 K and at pressures of 15 Torr ofhydrocarbon and 100 Torr of H[2]. Co-adsorption of tin and potassium onPt (111) resulted in the direct interaction between potassium, tin, andplatinum as verified by temperature-programmed desorption ofCO. Tindeposition yielded a maximum in the turnover rate as a function of Sncoverage for ethylene hydrogenation and cyclohexane dehydrogenation withmaxima at about 0.2 monolayers of tin and a turnover rate 75 percenthigherthan on clean Pt (111). This enhancement was explained by a lowerrate of deactivation as tin was added. In contrast, the addition ofpotassium to Pt and Pt/Sn produced only a monotonic decrease incyclohexane dehydrogenation. In an industrial system, where a higher tincoverage is used, interaction of tin with potassium may form an effectivesite blocker which could lower deactivation rates.

• Research Organization: Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
• Sponsoring Organization: USDOE Director, Office of Energy Research
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 900637
• Report Number(s): LBNL--40931
• Journal Information: Journal of Catalysis, Journal Name: Journal of Catalysis Journal Issue: 1 Vol. 178; ISSN 0021-9517; ISSN JCTLA5
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
CATALYSTS
CATALYTIC EFFECTS
CHEMICAL REACTION KINETICS
CYCLOHEXANE
DEHYDROGENATION
ETHYLENE
HYDROGENATION
PLATINUM
POTASSIUM
TIN