Study of Cu2O particle morphology on microwave field enhancement

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.