Structuring Nanochalcogenides using Ionic Liquids – NanoChalco

The success of this project lies in the gathering of researchers who specialize in the different domains needed to structure chalcogenides by means of ionic liquids.

(1) Preparation of ionic liquids.
(2) GeS2 nanomaterials have been obtained
(3) Solid-state NMR has shown that the anion of the ionic liquid is not present in the solid phase.
(4) A realistic model of chalcogenide surface has been built by means of ab initio calculations.

Developing a new synthesis route for nanochalcogenides by means of ionic liquids.

8 communications in conferences, 1 Article, 1 conference organization.

Chalcogenide glasses constitute an important class of materials, which are crucial for practical applications as optical fibers or waveguides for IR optics, active materials in memory storage, solid electrolytes for solid state batteries, chemical sensors for ecotoxic ions in aqueous media. As a result, the preparation, characterization, and use of bulk chalcogenide materials have been investigated in details. In contrast, the synthesis and characterization of nanochalcogenides such as nanoporous chalcogenide glasses have received only little attention. Obtaining in a controlled way such materials, which exhibit a large surface area from ~10 to 100 m2/g made up of highly polarizable atoms, is a very interesting challenge as it may lead to breakthroughs in various fields in which applications rely on the surface properties of host materials. Among important fields, nanochalcogenides could find an important place for practical applications in catalysis, phase separation, electrochemistry, etc. The aim of this project is to develop a new route for the synthesis of nanoporous chalcogenides by controlling their structuration using ionic liquids (ILs). The success of the present project relies on the gathering of researchers who specialize in the different fields needed to structure nanochalcogenides using ILs: (1) synthesis of ILs (including those with sulfur, phosphorus, boron, etc.), (2) chemistry of chalcogenide materials and their use in electrochemistry, (3) synthesis of ionogels and their use in electrochemistry, drug delivery systems, catalysis, and (4) characterization of interfacial and porous systems including ILs in contact with inorganic materials. As far as the latter point is considered, extensive and original use of NMR is planned in order to obtain structural information thanks to 1H/19F/33S NMR at high field which can probe the nanochalcogenide network, the IL and the interaction between both. We will also consider Dynamical NMR experiments which allow probing the IL dynamics from Å to µm.
Although the present project is submitted in the Programme Blanc, which devotes a large part to fundamental projects, we wish to conduct a task consisting of preliminary evaluation of the synthesized nanochalcogenide/IL systems. Two practical applications have been selected: (1) use of the nanochalcogenide/IL/lithium (or sodium) salt hybrid materials or nanochalcogenide/lithium (or sodium) salt inorganic materials as ionic conductors and (2) use of the nanochalcogenide materials (after removal of the IL) for gas phase separation (H2, CO2, etc.). A strong point of this project lies in the combination of both experimental and theoretical approaches. This strategy, which is an advantage in the characterization of the properties of nanoporous materials, will allow gaining insights into the role played by the interaction between the IL and the chalcogenide surface. A continuous feedback between the molecular modeling and experimental parts, will allow investigating the mechanisms and phenomena ruling the behavior of the hybrid systems composed of the chalcogenide material and the IL; molecular modeling offers a theoretical basis for the interpretation of the experimental data while experiments can be used to verify the theoretical predictions provided by the molecular simulations. In particular, while the interpretation of the experimental structural and surface characterization data is often ambiguous, molecular modeling can be used to disentangle the role of each phenomenon involved in the specific interaction between the IL and chalcogenide material (by playing with the chemistry of the IL/chalcogenide surface, concentration of the IL, size of the chalcogenide region, temperature, etc.).