INVESTIGADORES
PINTO Oscar Alejandro
congresos y reuniones científicas
Título:
ON THE LIMITS OF UNDERPOTENTIAL DEPOSITION IN THE NANOSCALE
Autor/es:
OVIEDO O. A.; PINTO O. A; REINAUDI L; LEIVA E. P.M
Lugar:
Querentaroa, México.
Reunión:
Congreso; The 64rd Annual Meeting of the International Society of Electrochemistry; 2013
Resumen:
Nanoelectrochemistry appears as a promising field
where researchers have been able to generate and control structures at atomic
and molecular level in order to obtain surfaces and structures with novel
properties. The main advantage of these types of methods is the precise control
that can be achieved in conditions of under/oversaturation of the interface. Electrochemical techniques that
were initially developed for the modification of surfaces, are now successfully
applied in systems with high rates of curvature. A widely used method for
the controlled modification of nanoparticles is underpotential deposition,
commonly called upd, in contrast with
overpotential deposition (opd). This
type of control method allows even allows to achieve fractions of a monolayer. Given the large curvature effects at the nanoscale, the upd process presents significant
deviations from metal deposition at flat surfaces. For example, an upd-opd
transition has been predicted with increasing nanoparticle size . Computer simulations have shown that in
the case of a Au nanoparticle decorated with Ag or Pd, the upd-opd transition occurs at about 4 nm and 5 nm in diameter,
respectively.
While many aspects of the electrodeposition
processes mentioned above can be explained, others remain yet to be understood,
leaving a fruitful field for theoretical and computational modeling. In the
present work, we present a phenomenological equation that allows
determination of the upd-opd transition for different metallic
nanoparticles at the nanoscale. Computer
simulations are used to demonstrate the main features of the modeling. This work is relevant for the control of size and shape of nanoparticles, using upd to block (or to favor) growth at the nanoscale.