Abstract
POMs are a class of inorganics that
have well-defined structures with attractive redox
activity, making them attractive for a variety of applications where multiple electrons need to be transferred, such
as electrocatalytic and photocatalytic energy conversion or
storage systems. For most of these applications, it is desirable
to have the POM attached to an electrode surface. Porous thin film
comprised of semiconducting nanoparticles are ideal surfaces to be derivatized
with electroactive material such as POMs because their high porosity allows for
the internal diffusion of solvent and electrolytes. Their effective surface
areas can be thousands of times greater than those of planar electrodes making
them ideal for high current applications and for enhancing the spectral
absorption of the film (these surfaces absorb in the UV but are transparent in
the visible). However, attaching POMs to
high surface area and transparent electrodes remains problematic.
Dr. Dares at FIU has developed conductive metal oxide
electrodes with surfaces modified
with polyoxometalates (POMs). The
electrodes are made of semiconducting nanoparticles
that can be any transparent metal
oxides. The semiconducting nanoparticles bond to the POMs through a
combination of electrostatic interactions and
hydrogen-bonding between
surface metal-oxygen atoms and POM oxygen atoms. The substrate comprising
the film of semiconducting nanoparticles is soaked or otherwise
contacted with a solution
of POM until the POM
is bonded to the semiconductor surface
and the residual solution is removed from
the porous transparent electrode.Benefit
Effectively mimic the electrochemistry of planar electrodesProvide numerous reductive processes stable in both aqueous and non-aqueous mediaRequire smaller amounts of POMOnly rely on diffusion of the substrate instead of diffusion of both POM and substrate to an electrodeCan be prepared and employed as high aspect ratio films which allow visible light to pass throughAllow for rapid of electron transferMarket Application
Electrocatalytic functions (e.g. sensing such as protein dynamics and other electrochemical functions)Photochemical applicationsNuclear fuel recyclingRenewable energy devicesPhotochemical processing (can be used with sunlight for smog abatementElectrocatalysts (e.g. electrocatalytic reduction of nitrous acid to NO, preparation of high-valent metal ions, including hexavalent americium for selective removal of Am from nuclear fuel)
