(3n) Integrating Alternative Solvent Systems with Electrocatalysis for Energy and Environmental Applications

                Energy and environmental
applications will remain main thrusts of interest in chemical engineering for
the foreseeable future and are more-and-more becoming tied hand-and-hand with
each other.  Resource type and uses, utilization efficiencies, and emissions
and other wastes all need to be addressed.  All of these issues have to be
addressed in a cost-effective and technically feasible manner.  I propose
adding tools from my PhD and post-doctoral experiences to my intellectual ?toolbox?
to address these problems.  I have a background in electrocatalysis,
heterogeneous catalysis and alternative solvent systems and will show how they
can be integrated together to give a stronger tool set to tackle the difficult
problems that lay ahead.

                In my PhD work at Ohio State, I
investigated nitrogen-containing carbon nanostructures (CN_x) as
alternatives to platinum for oxygen reduction reaction (ORR) electrocatalysts
in PEM and direct methanol fuel cells. In this work, CN_x
electrocatalysts were grown over removable oxide supports or unsupported metal
catalysts.  The nanostructure growth catalyst and growth reactant gases were
selected to control the nanostructure and nitrogen content of the resulting CN_x. 
The nature of the active site for this class of ORR electrocatalysts has been
heavily debated in the literature.  CN_x nanostructure, nitrogen-type
and ?content were tuned to examine the nature of the active site.  The
catalysts were extensively characterized using traditional heterogeneous
catalysis experimental techniques including X-ray photoelectron spectroscopy
(XPS), transmission electron microscopy (TEM), surface area analysis,
thermogravimetric analyses and other temperature-programmed experiments.  The
catalysts were electrochemically tested for activity and selectivity to
correlate the catalyst properties with desired activity and selectivity to
ORR.  Results of this work suggested that an active site containing nitrogen
and not a metal ion existed on the graphitic edge plane of the active
electrocatalysts. 

                During my post-doctoral experience at
Georgia Tech, I have worked on using alternative solvent systems to reduce
emissions, decrease process energy consumption, increase product separations
and improve desired reaction pathways and kinetics.  In this poster, I will
focus on the use of reversible ionic liquids (RevILs) as a tunable medium for
separations.  The main application that will be highlighted with these RevILs
is CO₂ capture from coal-fired power plants.  Here we use
one-component silylamines as the RevIL.  In this system, the excess water
typically used in amine-based CO₂ capture absorption systems is not
required.  This results in the possibility of significantly reducing the energy
of regeneration of the absorbant system while maintaining high CO₂
capture capacities.  The silylamines selected are a molecular liquid before CO₂
capture.  Upon reaction with CO₂, they form an ionic liquid with an
ammonium cation and a carbamate anion.  With a moderate increase in temperature,
the RevIL will reverse back to the molecular liquid, resulting in the release
of a purified CO₂ stream.  The chemical structure of these
silylamines can be altered to tune the desired properties of the absorption
system including CO₂ capture capacity, energy of regeneration,
viscosity and CO₂ release purity.  The modified silylamines have
been studied to develop structure-property relationships.  With these
established structure-property relationships, viable RevIL candidates for CO₂
capture absorption systems can be identified and further studied in the
laboratory.

                The two research areas presented in
the poster can be combined by using the alternate solvent systems in the
pre-processing of reactants, post-processing of products or as the electrolyte
itself in the electrochemical system.  Electrocatalysts will be developed that
are both active and selective to the desired reaction.  The synergetic effects
of use of the electrocatalysts with the solvent systems will be examined in the
systems studied.