The Effects of Particle Size, Morphology, and Mass Loading on the Reactivity of Nanocatalytic Particles

Nanocatalytic particles of Gold (Au), Platinum (Pt), and Palladium (Pd) are highly reactive at room-temperature and can be used to generate heat in micro-scale devices for portable power generation. No pre-heating is required for light-off and high steady-state operating temperatures can be sustained with high density alcohol-air premixtures. Preliminary experiments conducted in our lab and those reported by Hu and co-workers at Oak Ridge National Lab have measured peak operating temperatures ∼ 300–500 degrees Celsius using near-stoichiometric methanol/air and ethanol/air premixtures at ambient initial temperature and atmospheric pressure. The effect of particle size, morphology, mass loading, and flow residence time are reported for different mixture stoichiometries. Temperature measurements and gas species analyses are also tabulated. Interestingly, smaller particles were observed to be less reactive than larger particles for the same mass loadings for select conditions. Materials characterization of the particles has also been conducted to characterize the specific surface area of the catalyst and evaluate the importance of particle sintering, morphology changes, and particle distribution.