Hystor

 

ANR : HySTOR

Novel high surface carbon-hybrid materials for enhanced hydrogen storage

ANR : Gestion des variabilités spatio-temporelles des énergies (DS0204) 2014

Project ID: ANR-14-CE05-0009

Project coordinator: Lucyna FIRLEJ (Laboratoire Charles Coulomb)

Dates : December 2014 - November 2018

The idea

We propose a new, non-conventional approach of synthesis of a new class of porous, carbon-based hybrid materials which aim to be optimal adsorbents of hydrogen for mobile applications. The project addresses both theoretical and experimental aspects of the problem of efficient H2 storage by physisorption. The proposed research protocol includes all aspects of development of new material for practical application: 1) the synthesis of new adsorbents, 2) their characterization, and 3) multiscale numerical modeling.

1) The synthesis of the porous systems will use the arc discharge approach which has been used for over 20 years to produce fullerenes and carbon nanotubes. This technique will be first optimized to obtain fragmented graphene structures of nanometric size. Then we will incorporate heteroatoms (B, Be, N or mixture of them) during the synthesis of the carbon scaffolds. It has already been proved that large quantities (up to more than 30 %) can be incorporated into such carbon structures using high temperature techniques (such as arc discharge but also laser ablation or magnetron sputtering). These methods, already used for the synthesis and doping of carbon nanotubes, requires high temperatures, typically around 3000 K. The advantage of arc discharge approach is the possibility to prepare significant quantities of material for in depth characterization. It will also be possible to upscale this approach in a future step. The main challenge of this project will be the optimization of existing procedure to obtain porous ensembles of graphene scaffolds (nano-fragments) with a high percentage of carbon atoms substituted by boron and /or nitrogen atoms.

2) A large variety of techniques will be used to fully characterize the synthesized structures. Samples morphology will be analyzed using transmission electron microscopy. Spatially resolved electron energy loss spectroscopy (EELS), NMR and Raman investigations will be carried-out to check for the actual substitution of carbon atoms by heteroatoms and quantify the substitution rate. Nitrogen and argon physisorption will be used to determine the samples’ specific surface and pore size distribution. The energies of adsorption will be measured using calorimetric methods. The hydrogen adsorption measurements will be performed both at low temperature (around 77 K) and at room temperature and up to pressures of 200 bars. The final storage capacity of the materials will be estimated from hydrogen isotherms.

3) These experimental aspects will be supplemented by the multi-scale numerical modeling of the structural stability, binding energy of adsorption and the simulations of isotherms of hydrogen adsorption. The role of the numerical research will consist in guiding the experimental synthesis, proposing a microscopic mechanism of adsorption and complementing the material characterization by information that is not accessible from experimental data (for example, models of distribution of substituted atoms, distribution of the energy of adsorption and local density of the adsorbed hydrogen). This information will provide a feedback for optimization of the experimental procedures, especially for more effective search of the substitution procedure and synthesis.

Our Role in the project

Our group will play two roles. The first will be to use molecular modeling in order to predict the most interesting carbon based adsorbents for experimental study.

The second role will be experimental. However, the measurement of hydrogen adsorption in materials is not trivial. This especially the case when one is aiming to also directly measure the interaction energies using calorimetry. Nevertheless, it is these experiments which will show whether a material is of potential interest and such experiments which are vital in order to validate the theoretical approaches.

Two parameters are essential for success. The first is to obtain uptakes which can be used on real devices as explained in the state of the art above. The second parameter is the interaction energy of 15 kJ/mol of above. A three tier approach will be taken here.

(i) As a major deal breaker is the interaction energy, a screening approach will be made on samples where adsorption energies will be measured at 77 K and to 1 bar. These experiments will be performed using calorimetry @ 77K which is in a secured laboratory devoted to hydrogen. Samples which show promise (i.e showing adsorption energies >10 kJ/mol) will be used in the second stage.
(ii) The second parameter is the hydrogen uptake at pressures relevant to various storage scenarios. In a first case, isotherms will be obtained to 100 bar at various temperatures from 30K to 330K.
(iii) The final stage of this work will be to measure isotherms and energies for hydrogen at 303 K and up to 80 bar, and eventually 200 bar.

Partners

Laboratoire Charles Coulomb (L2C), Montpellier

  • Lucyna FIRLEJ ©, Christophe GOZE-BAC, Matthieu PAILLET

Laboratory of Multimaterials and Interfaces (LMI) Lyon

  • Catherine JOURNET-GAUTIER, Arnaud BRIOUDE, Bérangère TOURY

MADIREL Marseille

  • Bogdan KUCHTA, Philip LLEWELLYN, Marie-Vanessa COULET

Meetings

  • Kick-off : Dec 2014

Publications in HySTOR

 

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