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Contact : Jean-François Hochepied

The primary research of the Laboratory of Colloidal Systems in Industrial Processes (« Système Colloïdaux dans les Procédés Industriels » i.e. SCPI, a research team of the « Centre des Matériaux » — Mines ParisTech) is devoted to studying (co)precipitation in aqueous solutions.
Work focuses on the synthesis of metallic (hydr)oxides with particle sizes ranging from a few nanometers to several microns. During recent years, Al, Si, Ti, Fe, Co, Ni, Cu, Zn, Y, Hf and Ce (hydr)oxides particles (as well as some doped or mixed compositions) were synthesized for applications in cosmetics, nanomedicine, batteries, photocatalysis...

Our objectives consist of providing robust tools to control particle size and morphology, with various industrial constraints in mind. In order to stick to industrially, economically and environmentally acceptable processes, we favour aqueous chemistry and emphasize the control over particle size and morphology thanks to simple physico-chemical parameters (pH, temperature...) and processes (double jet or homogeneous precipitation). Often the desired particles are not directly precipitated; instead a solid precursor (i.e., an amorphe) which is subsequently crystallized is produced. Uncoupling of amorphous precipitation and crystallization stages of particle preparation allowing the use of different physico-chemical conditions at each stage has been shown to be critical in controlling the nature and characteristics of the final particles.

We used this strategy in many studies (boehmite, zinc oxide, titanium dioxide, hafnium germanate...) to control particle size and shape from very simple amorphous precipitates. The applications concerned are highly varied and have been the object of academic and industrial collaborations for over 10 years : particles for catalysis, photocatalysis or hydrogen photoproduction, for batteries, nanoparticles as ceramic precursors (thermoelectrics, fuel cells, ferroelectrics), photochromic particles for cosmetics, X-ray absorbers for nanomedicine...

 

 

The laboratory combines materials and industrial process research. The particles studied are principally metal hydroxides and oxides synthesized by precipitation of an amorphe followed by crystallization, by either double-jet precipitation at controlled pH or heat induced homogeneous precipitation. The lab is particularly interested in the role of pH on particle characteristics (size, morphology and crystallinity) in the double-jet precipitation of boehmite fibres, zinc oxide (with a morphology transition from non-starlike to starlike as a result of a strictly controlled pH change of only 1 unit) and nickel hydroxide.
The decoupling of the precipitation and crystallization steps has been exploited for the synthesis of boehmite nanoparticles (of varying crystallinity), hafnium germinate and titanium dioxide. Heat induced homogeneous precipitation can be separated into 3 variants : synthesis of yttrium or magnesium hydroxycarbonates by urea decomposition, destabilization of aminocomplexes (nickel, cobalt) and thermohydrolysis (titanium dioxide, tin oxide).

 


Partnerships and projects :

The studies at the laboratory are often conducted through direct collaboration with industry or as part of consortium in ANR or european projects.

ANRFerroEnergy

fp7IdealCellPhotomem

 

Main academic collaborations :

 

Main industrial collaborations :

LVMHSolvay
ErametUmicoreNanobiotix


 

 

Mines ParisTech Centre des Matériaux

 

EMA

 

ICMCB

 

Centrale-Paris

 

IMPMC

 

Itodys

 

LPS

 

LSPM

 

LNE

 

Institut de Chimie de Lyon

 

C2P2

 

Sapienza