Adsorption of CO and H/sub 2/ on (five) single crystal planes of Pt

Book · Sat Jan 01 04:00:00 EST 1977

OSTI ID:5864371

McCabe, R W

Adsorption of CO and H/sub 2/ on (five) single crystal planes of Pt was studied by flash desorption mass spectroscopy and Auger electron spectroscopy. Carbon monoxide binding energies were 26-36 kcal/mole, with the highest values on 210 and 211 planes and lowest on 110 planes; there were 3-4 binding states on 100, but only one on 111 and 110 planes. Sticking probabilities, always > 0.2, were lowest on the high symmetry 100 and 111 planes and highest on the more open 110 and 210 planes. Hydrogen binding energies were 12-27 kcal/mole, highest on 100 and lowest on 110 and 111 planes, with > 5 binding states on 100. Carbon monoxide desorption was first-order, but hydrogen desorption was second-order. Adsorption on surfaces covered with an oxide monolayer resulted in formation of higher energy binding states not found on the clean surfaces, but the oxide monolayer did not affect adsorbate densities. Sticking probabilities on the oxide monolayer were slightly lower for CO and higher for H/sub 2/. The enhanced bonding on the oxide can be interpreted in terms of microfacets, electronic structure alteration, or compound formation.

• OSTI ID: 5864371
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ADSORPTION
BINDING ENERGY
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYSIS
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMISORPTION
DESORPTION
ELEMENTS
ENERGY
HYDROGEN
METALS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PLATINUM
PLATINUM METALS
SEPARATION PROCESSES
SORPTION
SORPTIVE PROPERTIES
SPECTROSCOPY
SURFACE PROPERTIES
TRANSITION ELEMENTS