(318b) Controlled Manufacturing of Nanostructured Catalyst Particles Using Atomic Layer Deposition

Core-shell nanoparticles have high potential in heterogeneous catalysis. The interaction between host material and the coating gives additional degrees of freedom in the design of catalysts. We have applied the Atomic Layer Deposition (ALD) to provide particles with an ultra-thin, uniform layer. This technique is different from CVD in that the chemistry is split into two half-reactions; the different reactant gases are fed to the sample consecutively rather than simultaneously. The number of repetitions of the cycle determines the thickness of the coating, resulting in a well-controlled deposited layer at the atomic level. The quality of the layer is determined by the surface coverage in the adsorption step.

Ferguson et al. (2000) showed that ALD to particles is best carried out when these particles are fluidized, ensuring good gas-solids contacting. We recently showed that ALD of fluidized particles can also be carried out at atmospheric pressure (Beetstra, 2009) which simplifies the fluidization of the particles and facilitates scaling up of the process. In this paper, we will show that in this way, we are able to create catalyst nanoparticles in a controllable and scalable way.

References

Ferguson, J.D., Weimer, A.W., George S.M. (2000), ?Atomic layer deposition of ultrathin and comformal Al2O3 films on BN particles', Thin Solid Films 371, 95-104.

Beetstra, R., Lafont, U., Nijenhuis, J., Kelder, E.M., van Ommen, J.R. (2009), Atmospheric Pressure Process to Coat Particles using Atomic Layer Deposition, Chemical Vapour Deposition, in press.