Nanoparticles deposit location control on porous particles during dry impregnation in a fluidized bed

Laurie Barthe (1) , Karine Philippot (2) , Bruno Chaudret (3) , Nadine Le Bolay (1) , Mehrdji Hemati (1)

1 LGC - Laboratoire de Génie Chimique
2 LCC - Laboratoire de chimie de coordination
3 LPCNO - Laboratoire de physique et chimie des nano-objets

Thiswork deals with the synthesis of composite materials, catalytic or not, by an innovating technique named dry impregnation in a fluidized bed. This process permits the obtainment, in only one apparatus, of composite materials which, by the traditional way, must successively undergo the stages of impregnation, filtration, drying and calcination/activation. Its principle consists in the spraying of a solution containing a metallic precursor into a hot fluidized bed of porous particles as a chosen support. After the impregnation step, the decomposition of metallic precursor and metal activation can be operated in the same reactor. It is found that the competition between two phenomena (drying and capillary) controls the deposit location. This paper presents experimental results obtained during the dry impregnation of coarse and fine porous particles using different types of precursors: inorganic precursors (metallic salts), metal organic complexes and a colloidal suspension containing preformed metallic nanoparticles (rhodium). The effect of drying parameters (solvent content in gas phase and temperature) on deposit distribution within the support grains at the local scale is examined. It appeared that a fast drying leads to a deposit located only at the external particle surface (similar to a surface coating), whereas a uniform deposit on thewhole particle volume is obtained with slow drying conditions. It indicates that dry impregnation in fluidized beds is very flexible and, by a simple modification of the operating conditions, we can fix the deposit location.

Mots clés: Metallic nanoparticles; Dry impregnation; Deposit location; Fluidized bed; Drying

Domaines: Génie chimique

Laurie Barthe, Karine Philippot, Bruno Chaudret, Nadine Le Bolay, Mehrdji Hemati. Nanoparticles deposit location control on porous particles during dry impregnation in a fluidized bed. Powder Technology, 2014, vol. 257, pp. 198-202. ⟨10.1016/j.powtec.2014.02.040⟩. ⟨hal-01136567⟩