Influence Of Microwave Frequency And Power On Nanometal Growth

The rapid heating rates (Delta T/delta t) achieved in a microwave (MW) reactor has been shown to accelerate reaction rates due to the direct power absorbed (P-abs) into the ti 0 reactants leading to faster kinetics. The P-abs is proportional to the dielectric cross section of 130. the materials as defined by the real (epsilon') and imaginary (epsilon '') components. In a nanocrystal, the dielectric cross-section will be frequency dependent as well as size dependent. In this g co 20work, the frequency dependent growth of nickel nanocrystals at frequencies of 2.4S, 15.50, 0 and 18.00 GHz at constant Delta T/delta t was studied to evaluate the frequency dependence on MW growth of Ni. A scaling law behavior for growth rates is observed that is shown to 10 depend on the MW electric field strength. A relationship is derived between the "configurational energy" of the precursor molecules and the final nanoparticle size. The study provides a clear description of a microwave effect that is dependent on the frequency and power of the microwave and offers further insight into the physical chemistry of microwave applications to nanomaterial synthesis.