Our
research involves the synthesis by molecular design
of catalysts, surfaces, ceramics, adhesives and other
materials. Characterization of the structural, surface,
bulk, optical, magnetic, electronic, morphologic and
thermal properties of these materials is also a vital
part of this work.
Porous Manganese Oxide Octahedral
Molecular Sieves
The goals of this project are to prepare and characterize
single and multiple framework substitutions in various
octahedral molecular sieve (OMS) and octahedral layer
(OL) systems; to prepare and characterize new OMS and
OL structures and compositions; to understand factors
that control conductivity, magnetic, and structural
properties of nano-sized OMS systems; to fully characterize
physical and chemical properties of the above-mentioned
systems; to develop novel characterization methods for
OMS systems; and to use nanosize porous metal oxides
for selective oxidations, shape selective oxidations,
spintronic, and membrane applications. Synthetic studies
focus on single and multiple framework substitutions;
novel structures; and the use of OMS papers as supports
for multi-redox reactions. Characterization is done
with a variety of well developed methods as well as
more novel methods like in situ synchrotron diffraction
in collaboration with Jon Hanson at Brookhaven National
Lab (BNL), small angle X-ray scattering (SAXS) and small
angle neutron scattering (SANS) at Argonne National
Lab (ANL); and synchrotron photoelectron spectroscopy
with Dr. Dave Mullins of Oak Ridge National Lab (ORNL).
Novel selective catalytic oxidations of fluorene; isophorone;
toluene; enantioselective selective oxidations via kinetic
resolution of alcohols; and syntheses of pharmaceutical
intermediates will be done. Control of conductivity
in a variety of framework and tunnel substituted OMS
systems will be sought for potentials studies as fuel
cell electrodes, secondary nonaqueous rechargeable batteries;
and electrocatalysts. This project is funded by the
Office of Basic Energy Sciences, Division of Chemical
Sciences of the U.S. Department of Energy.
Synthesis of Nano-Size Catalysts Via
Microwave Heating
The focus of this research is synthesis
of porous nano-size zeolites, metal oxides and their
use in catalytic reactions. The synthetic work focuses
on preparation of new morphologies of nano-size porous
octahedral molecular sieves, porous transition metal
oxides, layered materials, and spinels. A novel method
of in situ mixing (I) ultrasonic nozzle (N) and microwave
(M) or INM synthesis technique was developed to prepare
hexametal oxide acrylic acid catalysts, octahedral layer
materials as selective alcohol oxidation catalysts,
and co-precipitated Cu/Zn on Al2O3 steam reforming of
methane catalysts. Catalytic activity of the catalysts
made with microwaves led to enhanced rates of reaction.
Often this was due to unique chemical properties of
the catalysts such as increased surface area or changes
in the oxidations states of active components. The synthesis
studies showed that nano-size materials with unique
chemical and physical properties could be produced and
this was extended to other metal oxides of Ni. A major
focus of the catalytic work was the microwave activation
of methane in the presence of catalysts such as Ni,
Fe, and activated carbon. Coupling to higher hydrocarbons
and aromatics was found. Other microwave driven reactions
include decomposition of Freons, desulfurization of
spent auto catalysts, decomposition of NOx, and the
activation of long chain hydrocarbons like decane in
microwave fields. A notable accomplishment was the activation
of such hydrocarbons with minimization of coke. In addition,
markedly enhanced ion migration in zeolites was noted
in a microwave field. In the area of methane activation,
a microwave frequency effect was clearly demonstrated
for the first time. Environmental remediation of contaminated
soils with microwaves was also demonstrated. A final
area of our research involves INM preparation of nano-size
inorganic materials with thin protective coatings of
organics.
Coatings of Inorganic Oxides and Surfaces
This work involves the coating of metals, ceramics,
catalysts, polymers and glass surfaces with various
coatings. Much of this work involves protective coatings
and stabilization against corrosion and oxidation. Replacement
of toxic coatings such as chromium materials is a focus
of this work. Inorganic organic (polymer) hybrid materials
are being done to exploit properties of both materials.
Various synthetic methods are used including sol-gel,
layer by layer deposition, atomic layer deposition,
electroplating, electroless plating, and others. Applications
in adhesion, adsorption, catalysis, batteries, and other
areas are being investigated.
High Temperature Ceramics
High temperature ceramics are important
materials for the development of engine parts. We are
collaborating with researchers at United Technologies
Corporation, East Hartford, CT to produce ceramic materials
that are stable at high temperatures (1000 °C and
above). Silicon carbide, SiC-coated boron, and Al2O3
fibers are being coated by chemical vapor deposition
techniques to produce strong materials.
Selected references
1. Crisostomo, V.; Ngala, K.; Suib, S.
L., New Synthetic Route, Characterization, and Electrocatalytic
Activity of Nano-sized Manganite, Chem. Mat., 2007,
19, 1832-1839.
2. Ngala, K.; Dobley, A.; Suib, S. L., Characterization
and Electro-catalytic Behavior of Layered Li2MnO3 and
its Acid-Treated form, Chem. Mat., 2007, 19, 229-234.
3. Ibe, M.; Gomez, S.; Malinger, S.; Fanson, P. Suib,
S. L., Microwave-assisted Desulfurization of NOx Storage-Reduction
Catalyst", Appl. Catal. B, 2007, 69, 235-239.
4. Shen, X.; Hanson, J.; Suib, S. L., In-situ Synthesis
of Mixed-Valent Manganese Oxide Nanocrystals: An in-situ
Synchrotron X-ray Diffraction Study, J. Am. Chem. Soc.,
2006, 128, 4570-4571.
5. Malinger, K. A.; Ding, Y.; Sithambaram, S.; Espinal,
E.; Gomez, S.; Suib, S., Microwave Frequency Effects
on Synthesis of Cryptomelane-type Manganese Oxide and
Catalytic Activity of Cryptomelane Precursor, J. Catal.,
2006, 239, 290-298.
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