Miguel
Jose Yacaman, PhD
Reese
Endowed Professor in Engineering
| Office: |
CPE 5.404 |
Mailing Address: |
| Phone: |
(512) 232-9111 |
The University of Texas at Austin |
| Fax: |
-- |
Department of Chemical Engineering |
| Email: |
yacaman@che.utexas.edu |
1 University Station C0400 |
| UT Mail: |
C0400 |
Austin, TX 78712-0231 |
Educational Qualifications:
Ph.D., National U. of Mexico (1972)
Research:
My research interests have always been very broad. However,
my primary interest has been the
structure and properties of nanoparticles including metals,
semiconductors, and magnetic materials. I have done research
on: synthesis and characterization of new materials most
of them nanoparticles, surfaces and interfaces, defects
in solids, electron diffraction and imagining theory,
quasicrystals, archaeological materials, and catalysis.
Research in Nanotechnology
At the present my main interest is related to nanotechnology
research. The field of nanotechnology and its applications
is an emerging field in which the science is rapidly
developing. A particular aspect which is my main interest
is the research
in nanoparticles capped with an organic molecule. This
are also called in the literature monolayer protected
clusters (MPC) or single Nanocrystals (NC´s) and
show many exciting applications in the materials science
such as;
nanoscale electronics, electroptics, electronic inks,
molecular machines, optical filters and switches among
others. They
also appear very interesting as chemical platforms
in; catalysis, chemical reactions, nano-sensors, polymer
additives
and also for some biological applications such as;
sio-sensing and drug-delivery[i],[ii],[iii]. Research
into the properties
of capped nanocrystals or MPCS has recently matured
into a field that is both fundamental and wide-ranging.
A mayor
source of motivation for research in those areas arises
from technological questions concerning ultimate limits
of the miniaturization of solid state devices.
- Properties and structure of nanoparticles capped
with an organic ligand molecule.
- Synthesis and properties of nanoparticle (NC´s)
superlattices.
- Synthesis and growth of nanorods of different materials
and the fabrication of ordered arrays of nanorods.
- The preparation of a new generation of catalysts
using new methods to prepare particles monodisperse
in size,
shape, internal structure, surface chemistry
on a porous support.
- The structure and potential role of atmospheric
nanoparticles in photocatalytic and thermal production
of atmospheric
pollutants.
- The synthesis and properties of fullerene-like structures
of layered materials, such as: MoS2, ReS2, WS2,
etc. and their applications to catalysis and lubrication
at
the
nanolevel.
Nanoparticles: Synthesis and Properties
The topic of the shape and structure of nanoparticles
has been extensively studied over the last 40 years for
the case of “bare” clusters. It is well known
that nanoparticles tend to assume structures which are
unlike the bulk state. For instance, they form structures
such as icosahedral, decahedral, star decahedral, truncated
decahedral, star decahedral, and truncated icosahedral.
In other cases, they follow the bulk structure and form,
for instance, a truncated octahedron or a cubo-octahedron.
However as mentioned before, the most exciting applications
of nanoparticles will be for the case when they are
capped with an organic ligand molecule. In this case
of such nanoparticles
much less information exists on the shape and crystal
structure. In the proposed research program we intend
to grow NC´s
and study in a systematic way the dependence of the
crystal structure and shape with the type of ligand and
conditions
of growth. We will use three different methods to grow
ligand capped particles:
a. Gas-vapor deposition at high pressures
b. Two phase reduction methods
c. Bioreduction methods
Nanorods; Synthesis and Characterization.
Nanoroads of metals gold have been recently synthesized
using electrochemical methods and in our group
by bioreduction methods. The nanorods appear to have
very
surprising properties. El Sayed et. al. has recently
reported that while NC´s of 35nm did not emit
light, nanorods are found to have a fluorescence of
quantum efficiency
which is 6-7 orders of magnitude higher than that of
the metal. Furthermore its wavelength maximum and quantum
efficiency
are found to increase linearly with increasing the
nanorod length. Also nanorods will find many applications
on the
buiding of mechanical and electronic nanodevices.
The methods of high pressure gas evaporation and bioreduction
can be used to synthesize nanorods. This represents a very
interesting system for practical application of nanorods
for the production of Au, Pt, Rh, Fe, and Mn. We will also
try to produce nanorods of some oxides such as MnO2 and
Mn2O3. The nanorods will be ligand capped and, therefore,
it will be possible to produce ordered structures of them.
Nanotechnology and Catalysis.
One of the goals of modern catalysis is to synthesize
well-defined monodispersed nanoparticles. This might represent
a very exciting breakthrough in the catalysis fields. In
order to achieve this goal, it is also important to control
the shape and the structure at the nanolevel. We propose
to grow nanoparticles by either of the three methods described
before, including the stabilization of the clusters on
an organic solvent. Then adsorption of the nanoparticles
on a high surface area support. Finally the process includes
removal of the support particles from the solvent and then
oxidation/reduction treatment to eliminate residual solvent
and surfactant.
Previous work has demonstrated that the size and shape
of the particle is determined by the first step[xi] which
gives the possibility of producing catalysts which are
monodisperse in shape, crystal structure, composition and
surface chemistry. We intend to produce Pt/Si02, Rh/Si02,
Pt/Rh/Si02, Pt/Al2O3 / Rh/Al2O, Pt/Rh/Al2O3. We will test
the catalytic properties at the catalysis laboratory in
Ensenada (UNAM), some well known reactions will be used
to compare their activity and selectivity with that of
catalyst prepared by standard reduction methods.
Selected Publications
- Structure And Catalytic Properties Of Nanostructured Molybdenum Sulfides. Camacho-Bragado, G. A., Elechiguerra, J. L., Olivas, A., Fuentes, S., Galvan, D., Yacaman, M. Jose. Journal of Catalysis 234(1), 182-190, (2005).
- Beyond Archimedean Solids: Star Polyhedral Gold Nanocrystals. Justin L. Burt, Jose L. Elechiguerra, Jose Reyes-Gasga, J. Martin Montejano-Carrizales, and M. Jose Yacaman. Journal of Cristal Growth, Vol. 285, Issue 4, Pages 681-691, (2005).
- On The Structure of Nanorods and Nanowires with Pentagonal Cross-Sections. Reyes-Gasga, J., Elechiguerra, J. L., Liu, C., Camacho-Bragado, A., Montejano-Carrizales, J. M., Yacaman, M. Jose. Journal of Crystal Growth 286(1), 162-172, (2006).
- Growth and Structure of Tio2 Thin Films Deposited Inside Borosilicate Tubes by Spray Pyrolysis. Miki-Yoshida, M., Antunez-Flores, W., Gomez-Fierro, K., Villa-Pando, L., Silveyra-Morales, R., Sanchez-Santiago, P., Martinez-Sanchez, R., Jose-Yacaman, M. Surface and Coatings Technology 200(12-13), 4111-4116, (2006).
- Thin Germanium-Carbon Alloy Layers Grown Directly On Silicon For Metal-Oxide-Semiconductor Device Applications. Kelly, D. Q., Wiedmann, I., Donnelly, J. P., Joshi, S. V., Dey, S., Banerjee, S. K., Garcia-Gutierrez, D. I., Jose-Yacaman, M. Applied Physics Letters 88(15), 152101-152103, (2006).
- Evidence of the Interaction of Evaporated Pt Nanoparticles with Variously Treated Surfaces of Highly Oriented Pyrolytic Graphite. Yang, D-Q., Zhang, G.-X., Sacher, E., Jose-Yacaman, M., Elizondo, N. Journal of Physical Chemistry B 110(16), 8348-8356, (2006).
- Two-Stage Melting of Au-Pd Nanoparticles. Sergio J. Mejía-Rosales, Carlos Fernández-Navarro, Eduardo Pérez-Tijerina, Juan Martín Montejano-Carrizales, and Miguel José-Yacamán. J. Phys. Chem. B, 110(26) pp 12884 – 12889, (2006).
- Low Dimensional Non Crystallographic Metallic Nanostructures: HREM Simulations Models and Experimental Results. J.L. Rodriguez, J.M. Montejano, and M. Jose-Yacaman. Modern Physics Letters B, Vol. 20, No. 13, 1-27, (2006).
- The Completion of the Platonic Atomic Polyhedra: The Dodecahedron. Montejano-Carrizales, J, Rodriguez-Lopez, JL, Pal, U, Miki-Yoshida, M, Jose-Yacaman, M., Small 2.3: 351-355, (2006).
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Presentation made to prospective graduate students 2005