Infrared spectroscopic investigation of the ethylene chemisorption reaction on supported metallic catalyst surfaces: ethylidyne formation on Pt, Rh, Pd, and Ru supported on alumina

Journal Article · Thu Jan 15 04:00:00 EST 1987 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100286a003· OSTI ID:6874795

Beebe, Jr, T P; Yates, Jr, J T

The reaction of ethylene with Pt, Rh, Pd, and Ru supported on alumina has been studied at 300 K by transmission infrared spectroscopy. Small metal particles of all four elements form the ethylidyne species, identical with CCH/sub 3/, and the vibrational frequencies of these species are in close agreement with those reported for ethylidyne adsorbed on the close-packed faces of single crystals of these same metals. The authors PT and Rh surface produce ethylidyne IR bands of higher intensity than Pd and Ru. This is consistent with the presence of smaller Pt and Rh average particle sizes, where quantitative CO adsorption measurements indicate an approximately 2- to 3-fold greater chemisorption capacity of Pt and Rh surfaces than Pd and Ru surfaces. In addition, Pt and Rh surfaces exhibit relatively strong ethylidyne asymmetric modes (nu/sub as/(CH/sub 3/) and sigma/sub as/(CH/sub 3/)), indicating that the surface-dipole selection rule is not strictly in operation on these surfaces. This weakening of the selection rule for Pt and Rh surfaces is consistent with the small average particle sizes for Pt and Rh (19 and 28 A, respectively) compared to larger average particle sizes for Pd and Rh (84 and 66 A, respectively).

• Research Organization: Univ. of Pittsburgh, PA
• OSTI ID: 6874795
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 91:2; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ABSORPTION SPECTROSCOPY
ALKENES
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CATALYSTS
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMISORPTION
DATA
ELEMENTS
ENERGY LEVELS
ETHYLENE
EXCITED STATES
EXPERIMENTAL DATA
HYDROCARBONS
INFORMATION
INFRARED SPECTRA
MEDIUM TEMPERATURE
METALS
NUMERICAL DATA
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PALLADIUM
PARTICLE SIZE
PLATINUM
PLATINUM METALS
RHODIUM
RUTHENIUM
SEPARATION PROCESSES
SIZE
SORPTION
SORPTIVE PROPERTIES
SPECTRA
SPECTROSCOPY
SURFACE PROPERTIES
TRANSITION ELEMENTS
VIBRATIONAL STATES