  The dielectric enhancement and modulation of a cuprous oxide (Cu2O)
microwave-active catalyst material is investigated from an experimental and
computational point of view. Experimental synthesis of two particle
morphologies that included a cube and spike were carried out using an EDTA
hydrothermal synthesis method. The permittivity for the spiked particles at low
volume fraction in a paraffin composite exhibited a 20% increase when compared
to the cube-shaped particles at the same volume fraction. Using a finite
difference time domain (FDTD) simulation, the improvement in permittivity was
attributed to the enhanced electric field near the tip of the spike particles
and the neighboring interaction at higher volume fractions. The increased
electric field at the tips of the particles induces a change in polarizability
(dipole density) within the matrix material, which increases the effective
dielectric properties of the composite. Furthermore, it was determined that an
electrically conductive particle within a high permittivity matrix material is
advantageous for generating high localized electric fields that can be utilized
for microwave-assisted catalytic reactions.
