A Scalable Turbulent Mixing Aerosol Reactor for Oxide-Coated Silicon Nanoparticles

Abstract

A new, turbulent flow aerosol reactor is described that enables synthesis of uniformly sized aerosol nanoparticles during a residence time of a few milliseconds. The short residence time allows processing of high number concentration aerosols, in excess of 10^9 cm^(-3), to be processed with minimal coagulation, leading to an aerosol throughput approaching 10^(11) particles cm^(-3) s^(-1). Turbulent mixing speeds thermal and chemical transport beyond diffusional limits inherent in laminar flow reactors, providing the thermal energy to drive chemical reactions, coalescence, densification, and crystallization of particles. With enhanced transport, residence time in the reactor can be reduced, thus limiting coagulate particle growth while maintaining a high throughput of nonlayered or multilayered aerosol particles. The turbulence that enables rapid mixing is generated by dissipation of kinetic energy supplied to the reactor by high velocity gas jets. The apparatus described here increased the throughput by a factor of 100 above previous laminar flow reactors, and the induced fast mixing enables scale-up to much higher throughput. Characterization of particles by differential mobility analysis and transmission electron microscopy confirmed uniformity in size and composition.

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