NANOSCALE ENERGY CONVERSION BY USING NANO-CATALYTIC PARTICLES

摘要

Burning or combustion is the most common energy conversion method of which the chemical energy stored is converted to the thermal energy during an oxidation process. Governed by the scaling and thermodynamic laws, there is a minimum size requirement (～1 mm) for having a sustainable reaction. Conventional combustion or burning usually takes place when the reactants' temperature is much higher than the body temperatures of biological beings. All heat engines including both external combustion engines and internal combustion engines were developed using this phenomenon; and reaction processes proceed in macroscale where big machines and large reaction chambers are often employed. As an attempt to mimic nature's method of energy conversion, without external ignition, nano-catalytic particles could be self-heated very rapidly (in seconds) in the present of methanol or ethanol vapor/air mixture flow. Stable and reproducible spontaneous self-ignition and self-supporting combustion have been achieved at room temperature by exposing nanometer-sized catalytic particles to methanol-air or ethanol-air gas mixtures. Infrared thermography revealed that the thermal gradient near nanoparticles could be more than 100 times higher than what could be achieved in macroscale. The reaction releases heat and produces CO_2 and water. Such reactions starting at ambient temperature have reached both high ( > 600℃) and low (a few tenths of a degree above room temperature) reaction temperatures. The reaction intensity could be easily controlled by varying the fuel-air mixture. The application of this discovery might lead to the development of a new class of solid state electrical power generators which could convert fuel energy to electricity without any moving parts.