(474d) Gas-Phase Synthesis of Functional Nanoparticles for Energy Applicationsin

In this study we establish an aerosol-based spray pyrolysis system to generate high purity metal oxide nanoparticles (NPs) with tunable particle size and composition. Copper oxide-based nanoparticle (CuOx-NP) and copper-aluminum oxide nanoparticle (CuAlOx-NP) are chosen as the representative material, and the CO oxidation is used as the model reaction. Differential mobility analysis (DMA) was employed to in-situ monitor the secondary particle size of the synthesized NPs in the gas phase, and the scanning electron microscopy was used for providing the particle imagery of the electrostatically-deposited NPs and the primary size distributions of NPs. Thermo-gravimetric analysis was employed to determine the required temperature of the pyrolysis process, and x-ray diffractometry was used to correlate the crystallite size of NP with the pyrolysis temperature. Temperature-programmed reduction system is employed to measure the ability in the oxidation-reduction of CuOx-NPs and CuAlOx-NP, which can be correlated to the ignition temperature and the conversion rate of catalytic reaction. Result shows that we can successfully synthesize CuOx-NPs and CuAlOx-NP with tunable size and composition with ability of in-situ characterization of physical size in gas phase (i.e., by DMA). By tuning the concentration and the composition of Cu and Al precursor, we can control the particle size and the morphology of nanoparticle. The reduction temperature of CuOx and the corresponding light-off temperature of the CO oxidation reaction can be effectively improved. Addition of Al precursor was found to affect the ability of reduction and catalytic performance. Our work provides a prototype study to fabricate CuOx-NPs and CuAlOx-NP with an optimal performance in catalysis. The results can be used to develop a correlation of material properties versus the oxidation-reduction ability and the catalytic activity, which have shown to be a strong indicator to the performance in the energy release and the ability in catalysis.