Nano-heaters: New insights on the outstanding deposition of dielectric energy on perovskite nanoparticles

Abstract

It has been experimentally observed that, in some Mott nanomaterials, outstanding dielectric losses may appear at microwave frequencies, leading to a rapid increase of temperature. This often takes place in association with the insulator to metal transition (IMT) in these materials. However, when other materials with a similar structure and composition are subjected to the same intensity of microwave (MW) irradiation, the observed heating is minimal. Here we show that the electron dynamics of these materials are responsible for their different heating behaviour. More specifically, for LaCoO3 perovskite nanoparticles, the spin shifts causing the IMT are also responsible for the observed heating behaviour. Under suitable conditions, the intense absorption of MW radiation leads to extremely high heating rates, above 600 degrees per second. The insight gained from this study has been used to design a directly heated catalytic system (LaCoO3 perovskite nanoparticles on a MW-transparent cordierite monolith) capable to operate under a stable, significant solid-gas temperature gradient.