Abstract View
Implementing On-line Laser Diagnostics to Monitor the Reactive Spray Deposition Technology (RSDT) for Catalyst Manufacturing
EVANGELOS K. STEFANIDIS, Thomas A Ebaugh, Stoyan Bliznakov, Leonard Bonville, Francesco Carbone, Radenka Maric, University of Connecticut
Abstract Number: 549
Working Group: Nanoparticles and Materials Synthesis
Abstract
The Reactive Spray Deposition Technology (RSDT) has been developed to synthesize nanoparticles in a flow reactor and deposit them directly on a target substrate. This flame-based method is proved to be effective for the manufacturing of highly active catalysts in a single step process but requires an optimization of the operative parameters to tailor the properties of the final products. The characterization of the produced nanoparticles necessary to achieve the process optimization is routinely performed off-line on samples of the final products, manufactured while keeping constant the process parameters. It appears that the implementation of laser diagnostics able to provide on-line information about the size, number concentration, crystallinity, and other characteristics of the synthesized nanoparticles, would substantially accelerate the process optimization due to on-line feedback about the sensitivity of the product properties to the process parameters. It would also offer the capability of monitoring slowly transient deposition processes of multilayered products with not-uniform characteristics such as size and crystallinity. In this study, we tackle the technical difficulties of implementing spectroscopic laser diagnostics in the complex RSDT flame reactor. A millimeter-sized measurement volume in the RSDT is illuminated by pulsed laser light with a wavelength of 532 nm while the induced light emission is collected at an angle by a train of optical components redirecting it into a spectrograph equipped with a fast gated and intensified CCD camera. Appropriate camera gating and light filtering allowed us to distinguish between the signals emitted by static light scattering, Stokes Raman scattering, and particle incandescence. The three signals are related to the number concentration, composition, and size of the light emitters in the measurement volume but the deconvolution of these properties is not trivial. Preliminary testing of a propane jet flame synthesizing Platinum nanoparticles gave promising results and the challenges of the quantitative result interpretation are currently being addressed.