INVESTIGADORES
FONTICELLI Mariano Hernan
congresos y reuniones científicas
Título:
Alkanethiols Adsorbed on Platinum and Palladium Surfaces: Composition and Stability Studies by Electrochemical Techniques and X-ray Photoelectron Spectroscopy
Autor/es:
M. FONTICELLI; G. CORTHEY; M. A.FLORIDIA ADDATO; ALDO A. RUBERT; G. BENITEZ; R. C. SALVAREZZA
Lugar:
Niza, Francia
Reunión:
Congreso; 61st Annual Meeting of the International Society of Electrochemistry; 2010
Institución organizadora:
International Society of Electrochemistry
Resumen:
The
platinum group metals (PGMs) have outstanding catalytic properties. They have
been widely applied in chemical, petrochemical, pharmaceutical, electronic, and
automotive industries. Among them, both Pd and Pt possess distinctive ability
in catalyzing partial oxidation, hydrogenation and dehydrogenation of a variety
of important molecules that are essential in many industrial processes.
Although carbon-supported PGMs -or their alloys- catalysts can be produced by
the widely used impregnation approach, such catalysts typically do not have the
uniformity in size, shape and composition among individual particles in
comparison to those made by colloidal or micro emulsion methods. In this
regard, thiolates have demonstrated to be the most versatile family of capping
agents for the synthesis of ligand-stabilized metallic and semiconductor
nanoparticles. However, the current knowledge with regards to PGMs-thiolate
interaction and thiolates self-assembled monolayers (SAMs) is poor in contrast to the
vast literature of thiolates and their SAMs on gold and silver.
In this work the stability
and composition of alkanethiols adsorbed on planar and curved (nanoparticles)
Pt and Pd surfaces was studied by electrochemical techniques and X-ray
photoelectron spectroscopy (XPS). With regards to the chemical nature of
adsorbates, thiolate-SAMs on Pt resemble those grown on Ag and Au. On the other
hand, alkanethiols adsorbed on Pd surfaces lead to a complex interface composed
of thiolate and sulphide[1],
which is possibly responsible for its high stability[2]. In the case of Pt, the SAMs start to be desorbed in
the hydrogen adsorption region, which makes the electrochemical desorption at
negative potentials a suitable alternative for nanoparticles cleaning. Therefore,
it has been considered the role that hydrogen may play in the SAMs desorption.
It is analyzed whether the ability to adsorb H can be correlated with the
stability of the SAMs on these metals.
[1] Love, J. et. al. J.
Am. Chem Soc. 125 (2003) 2597.
[2] Corthey, G. et. al J. Phys. Chem. C. 113 (2009)
6735.