Nanochemistry for the synthesis of nanoparticles and nanocomposites

Aldo Capobianchi - aldo.capobianchi@ism.cnr.it

Laboratory BC12 (nM2-Lab)

Roma - Monterotondo

The laboratory of nanochemistry for the synthesis of nanoparticles and nanocomposites is focused on the synthesis of magnetic and non-magnetic materials at the nanometer scale. The typical synthesized magnetic materials are nanoparticles of metal alloys with L10 structure (eg FePt, CoPt, MnPt, etc.), with peculiar magnetic properties that depend on the metals making up the alloy beside being of interest for various applications including biomedicine, magnetic recording and catalysis. Different methods of synthesis are also applied to the production of metallic nanoparticles such as Ag or Ru and semiconductors such as CdS. The laboratory is also characterized by the activity of synthesis of nanocomposites based on carbon nanotubes, graphene and graphene oxide linked to magnetic and non-magnetic nanoparticles. The synergistic effect gives particular properties to the nanocomposite compared to the individual components. Green synthesis methods are used for the synthesis of nanoparticles and nanocomposites. In particular, the mill grinding technique allows to obtain excellent results in terms of quantity of material produced and dimensional control at the nanometric level. The laboratory allows refined processing under controlled and reductive atmosphere for low oxidation states. The typical equipment of the chemical laboratory is enriched with vacuum lines and nitrogen lines mounted under fume hoods. The laboratory uses ovens and muffles for air treatments and a horizontal tubular oven for heat treatments in a controlled atmosphere.

TECHNICAL SPECIFICATIONS

Stirring/heating plates: various models, T_max 300°C.
Lines with rotary vacuum (P = 2x10^-3mmHg).
LB deposition apparatus: (Nordtest, KSV 5000)

AVAILABLE TECHNIQUES

Chemical synthesis and deposition of organic thin films and nanoparticles using the Lagmuir-Blodgett (LB) technique.

SAMPLES

Powders or crystals in typical quantities of the order of 100 mg. The easy scalability of the methods allows the preparation of larger quantities.
Organic thin films and nanoparticles with a maximum surface area of 10x10 cm² (by LB).

USED FOR

Permanent magnets
Catalysis
Sensors
Semiconductor / microelectronics
Cleaning and purification of water
Chemical industry

CASE STUDIES

Nanoarchitectures of FePt@MWCNTs/Ru with double functionalization.

The example shows the synthesis of nanocomposites with a complex three-component nanoarchitecture: carbon nanotubes (CNTs) that give a large surface, Ru nanoparticles (NPs) that decorate the CNTs and act as a catalyst and FePt NPs inside the CNTs that have the purpose of giving the nanocomposite a magnetic behavior. This last one has a dual function: the first and simpler is to move or remove the catalyst nanocomposite how it prefers in the reaction environment. The second and more complex is to provide local heating to the catalyst without heating the whole solution. Local heating is obtainable through an alternating magnetic field applied from the outside as occurs in the case of hyperthermia of magnetic NPs for therapeutic purposes. In the catalysis phase this can lead to a strong saving of energy and to a greater specificity of the reaction. The uniqueness of this work lies in the great control over the structure of the nanocomposites and the highly specific positioning (internal or external to the CNTs) of its components.

See: B. Astinchap,R. Moradian, A. Ardu, C. Cannas, G. Varvaro, A. Capobianchi. Chem. Mater. 24, 3393(2012)

Effective synthesis of L₁₀ alloy nanoparticles from stratified precursor salts.

An intelligent and easily scalable synthesis strategy, called Preordered-Precursors Reduction, has been successfully applied to synthesize highly ordered L₁₀ MPt (M = Fe, Co Ni, Mn) alloy nanoparticles under milder conditions than ordinary processes. The natural order of the crystalline M(H₂O)₆PtCl₆ precursor salts, consisting of M and Pt atoms on alternating planes that imitate the atomic disposition of the L10 structure, plays a fundamental role in providing all systems with a certain initial quantity of chemical order that facilitates the formation of the ordered phase L10, which is therefore obtained in milder conditions, in terms of process temperature and reaction times, compared to what is required by ordinary strategies.

See:

X.C. Hu, E. Agostinelli, C. Ni, G.C. Hadjipanayis, A. Capobianchi. Green Chem. 16, 2292 (2014)
G. Varvaro, P. Imperatori, S. Laureti, C. Cannas, A. Ardu, P. Plescia, A. Capobianchi, JALCOM, In press (2020)

Nanochemistry for the synthesis of nanoparticles and nanocomposites