Article,
Heat of Adsorption of Naphthalene on Pt(111) Measured by Adsorption Calorimetry
J. Phys. Chem. B, (2006)
DOI: 10.1021/jp062659i
Abstract
The heat of adsorption of naphthalene on Pt(111) at 300 K was measured
with single-crystal adsorption calorimetry. The heat of adsorption
on the ideal, defect-free surface is estimated to be (300 - 34 -
1992) kJ/mol. From this, a C-Pt bond energy for aromatic hydrocarbons
on Pt(111) of 30 kJ/mol is estimated, consistent with earlier results
for benzene on Pt(111). There is higher heat of adsorption at very
low coverage, attributed to step sites where the adsorption heat
is łeq330 kJ/mol. Saturation coverage, = 1 ML, corresponds to 1.55
� 1014 molecules/cm2. Sticking probability measurements of naphthalene
on Pt(111) give a high initial value of 1.0 and a Kisliuk-type coverage
dependence that implies precursor-mediated sticking. The ratio of
the hopping rate to the desorption rate of this precursor is 51.
Naphthalene adsorbs transiently on top of chemisorbed naphthalene
molecules with a heat of adsorption of 83-87 kJ/mol.
