(544aa) Cheap and Upscalable Process for Atomic Layer Deposition on Powder through Stoichiometric Grafting in Solution

Atomic layer deposition (ALD) is an efficient method for thin layer deposition based on alternate exposure of gaseous metal precursor and oxygen source. First designed for film deposition on wafers, there is now a growing interest in ALD for tuning heterogeneous catalyst surface properties. For instance, great improvement in catalyst stability has been achieved through deposition of alumina over catalysts in the fields of biomass conversion¹ and methane activation². Unfortunately, the high cost of equipment for deposition on powder and over consumption of expensive chemicals hinder the generalization of this technic in academic research and industry.

In this work, we designed a cheaper and upscalable process for atomic layer deposition on powder that required only standard inorganic chemistry equipment. The deposition follow the same surfaces reaction as ALD but with a control on stoichiometry, sparing time consuming purges and avoiding the waste of unreacted precursors. Beyond protective metal oxide deposition, our technic also open the door to multispecies grafting with controlled proximity allowing pairing or isolation of active sites.

As a proof of concept, alumina was deposited, from alkyl aluminum and water injections, on dispersed oxides. Influence of the support, the solvent and the precursor size on the grafting and cycling were assessed in order to demonstrate the flexibility of the method and to prepare the ground for a more accessible atomic layer deposition.

(1) O’Neill, B. J.; Sener, C.; Jackson, D. H. K.; Kuech, T. F.; Dumesic, J. A. Control of Thickness and Chemical Properties of Atomic Layer Deposition Overcoats for Stabilizing Cu/γ-Al2O3 Catalysts. ChemSusChem 2014, 7 (12), 3247–3251.

(2) Lu, J.; Fu, B.; Kung, M. C.; Xiao, G.; Elam, J. W.; Kung, H. H.; Stair, P. C. Coking- and Sintering-Resistant Palladium Catalysts Achieved Through Atomic Layer Deposition. Science 2012, 335 (6073), 1205–1208.