INVESTIGADORES
JASEN Paula Veronica
congresos y reuniones científicas
Título:
Hydrogen adsorption on Pt-coated B2-FeTi thin films: DFT study
Autor/es:
P. JASEN; E. GONZÁLEZ; G. BRIZUELA; A. JUAN; J. MARCHETTI
Reunión:
Congreso; Cuarto Congreso Nacional Tercer Congreso Iberoamericano de Hidrógeno y Fuentes Sustentables de Energía HYFUSEN 2011; 2011
Resumen:
The intermetallic B2-FeTi is
known as one of the promising material for reversible hydrogen storage. The capacity of FeTi for hydrogen
storage is about 37% (in volume).
FeTi has to store and release hydrogen at the atmospheric pressure and
room temperature in comparison with other perspective hydrogen storage
materials. However, this alloy requires an initial activation treatment. During activation treatment the surface
is covered by an oxide layer, which hinders hydrogen absorption. The formation of surface oxide layer
can be prevented by the usage of a thin layer of Pt as a cover. It is assumed that Pt coating or
alloying will be beneficial for hydrogen uptake because Pt is an active
material for hydrogen adsorption.
We have modeled this intermetallic and computed the electronic structure
in Pt-covered FeTi(110) surface using the VASP code with GGA approximation for
the exchange-correlation potential.
The electronic structure changes introduced by Pt and hydrogen in the
surface layers of B2-FeTi are analyzed.
We establish that the adsorption properties of clean pure B2-FeTi
surface are better when hydrogen can interact with both Fe and Ti atoms. This trend remains valid for Pt-covered
FeTi and H adsorption is easier for Pt/FeTi system. The Fe states are shifted towards the Fermi level, which its
highly reactivity in comparison with clean B2-TiFe. In the hollow position the H 1s energy level appears in the
energy range much closer to the Fe valence band than that of Ti. The position of H level depends
strongly on the adsorbate sites. In the case of Ti-top position, the noticeable
changes in electronic structure observed in the hydrogen-containing surfaces
are connected primarily with formation of strongly hybridized H s-states with
metal d-bonding states.