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Research

Professor
Viola Birss

 Canada Research Chair in Electrochemistry of Materials

(Fuel Cells & Related Energy Applications)

 

Current
Research Interests

One of the main goals of
our research is to produce useful thin film materials which can serve as
electrocatalysts in fuel cells, to protect metals from corrosion, to serve as a
matrix for enzymes for biosensor applications, and to create useful
nanoarchitectures for a wide range of applications.  Some examples of the
research currently underway in our group are given below.

 

Fuel Cell Electrochemistry

One of the most active
areas of current research is related to the development of new catalysts for
fuel cell applications, as well as to further the understanding of factors
which lead to the degradation of fuel cell performance.  Fuel cells are
energy conversion devices which are efficient, quiet, and environmentally
friendly.  In one branch of this research, we are working on novel methods
to form thin films composed of nanometer sized metallic or metal oxide
particles, using a derivative of the sol-gel technique. These are then tested
for their ability to serve as an electrocatalyst for hydrogen, methanol or
ethanol oxidation, or oxygen reduction, in low temperature PEM fuel cells. In
parallel to this, we are developing new low cost cathode materials for the
reduction of oxygen, and a patent on our newly developed materials has recently
been filed.  Other work, supported by NSERC and in collaboration with
Ballard Power Systems, is focused on the development of corrosion resistant and
very high surface area carbon support materials for PEM cathodes, in
particular, allowing better utilization of the costly Pt catalyst and enhancing
lifetime. We are also developing highly promising nanoarrays of dimples in
metal surfaces, allowing nanoparticles of controlled and uniform size to be
deposited into these small pores and then to be studied as an ensemble of
individual particles.  This will allow us to establish the real activity
of many important reactions as a function of known overall surface area and
known interfacial contact area.

Our work on solid oxide
fuel cells (SOFCs), funded by NSERC and a number of industry partners, is
focussed on enhancing performance and durability. We have recently developed
reliable methods to determine the kinetics and mechanisms of fuel oxidation and
oxygen reduction reactions, as well as on establishing the important effect of
electrode porosity on fuel cell performance. We are now using these methods and
working on the application of nanometer-sized electrocatalytic particles for
SOFC applications, with these materials showing great promise in terms of
enhanced performance. In another major SOFC project, which is part of the
national SOFC Canada NSERC Strategic Network (hubbed at the University of
Calgary, with Dr. Birss serving as co-Scientific Director), we are focusing our
efforts on understanding and overcoming the degradation of performance of high
temperature SOFCs.  The specific types of problems that are being
addressed include the effect on anodes of sulfur in the fuel, how to recovery
sulfur-poisoned anodes, how to minimize problems encountered when Ni is exposed
to air when the anode is still hot, the impact of Cr that is released from
stainless steel interconnects on cathode behavior, and the deleterious effect
of thermal cycling. Some of our more recent efforts are addressing increasing
SOFC performance and resistance to poisoning through the use of mixed
ion-electron conducting anodes. Another recent project has been directed
towards further improving the performance of microtubular SOFCs, in
collaboration with the Alberta Research Council and now also part of the SOFC
Canada Network research program. 

Protection of Metals from
Corrosion and Wear

In another major branch of
our work, funded by Honeywell Inc., the primary research goal is to
electrochemically produce a thick, protective oxide film on the surface of
specialized light weight Al and Mg alloys, to be used in aerospace
applications.  In the case of the Al alloys under study, they contain a
relatively high percentage of Cu (up to 6%).  Therefore, most solutions
and approaches normally employed to anodize Al will result in the dissolution
of Cu, thus leaving the surface in a porous and weakened condition. The goals
of our work are to develop anodizing methods that will result in the formation
of a uniform, thick, and adherent film over the entire alloy surface, resistant
to penetration by water or chloride ions. In other work, we are developing
anodization methods to generate stable, high aspect ratio, metal oxide
nanotubes, for use in a wide variety of applications.

Metal Electrodeposition

A recent project, also
funded by Honeywell Inc., is focussed on the electrodeposition of metal coatings
on steel surfaces to enhance their wear protection, and some very promising
coatings have been developed. We are also active in the area of the
electrodeposition of a range of metals to produce controlled nanostructures for
a variety of applications.

Biosensor Development

The research in this area,
funded by NSERC and involving collaboration with Prof. Hanna Elzanowska (Univ.
of Warsaw), is aimed at developing a stable glucose biosensor for the treatment
of diabetes. This is being accomplished by embedding an enzyme, glucose
oxidase, into a porous, conducting matrix of nanoparticulate Ir metal or Ir
oxide (IrOx) thin films.  In the presence of oxygen, the enzyme reacts
with glucose, forming hydrogen peroxide, which is sensed as current at the IrOx
electrodes.  Without oxygen, IrOx reacts directly with the enzyme,
delivering current and regenerating its active flavin site after each reaction
with glucose.  Ir-based electrodes have been chosen because they are
stable to dissolution, are conducting, and most importantly, they are tolerated
well by the body.  Our present work is focussed on the optimization and
fabrication of a continuous-glucose biosensor, for use as a novel in vivo
artificial glucose homeostatic control system. Future work will be directed
towards other redox-active enzymes, benefiting from the advantageous properties
of IrOx thin films.

Hydrocracking Catalyst
Development

Collaborative work with the
Pereira group (Dept. of Chemical Engineering, U of Calgary), supported by NSERC
and Nova Chemicals, is also underway. This involves the synthesis and
characterization of zeolitic and mesoporous structures containing metal
nanoparticles that will crack aromatic compounds formed during the processing
of heavy oil.