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The Hydrogen Sector: Platinum-free Catalytic Material

http://www.bulletins-electroniques.com/actualites/61852.htm

Using hydrogen as an energy vector is an attractive solution. However, the hydrogen power sector cannot grow unless two key steps are controlled: one, the mass production of hydrogen by water electrolysis in devices called electrolyzers and two, the use of hydrogen in fuel cells to supply energy thanks to hydrogen oxidation. Today, the required catalyst for the processes is platinum that is needed to accelerate a chemical reaction. The problem is that the metal is extremely rare on our planet (to the order of 5ppm, equivalent to that of gold) making it very expensive. So, it is a major challenge to replace platinum.

Current research to replace platinum with low-cost abundant metals draws on the chemical processes at work in certain living organisms. They have amazing enzyme systems called hydrogenases that only use abundant metals such as iron and nickel, which enable them to use hydrogen as an energy source or produce it from water. The enzymes are a unique source of inspiration for chemists synthesizing nickel- and iron-based compounds, structurally similar to hydrogenases, and developing new catalysts. This is called bioinspired chemistry. However, similar to platinum, the electrodes must be coated in very large amounts of the synthetic catalysts before they can be used in technological devices. Thanks to the geometry of carbon nanotubes, which makes it possible to increase the potential bonding surface for the catalyst dramatically, and to their high electric conductivity, the tubes afford a solution for overcoming this problem.

In their study, the researchers from different CEA laboratories (1) used a covalently bonded graft to immobilize one of the bioinspired nickel-based catalysts on carbon nanotubes. The resulting material shows promising catalytic activity for both the production and use of hydrogen. The material also proves to be extremely stable and capable of functioning in a highly acidic medium, making it compatible with proton exchange membranes, which can be found in virtually all low temperature fuel cells.

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[1] CEA Laboratories involved:
- Laboratoire de Chimie et Biologie des Métaux, (LCBM, Metal Chemistry and Biology Laboratory) (CEA/CNRS/Grenoble J. Fourier University), Institut de Recherche en Technologies & Sciences du Vivant (Institute for Research on Life Sciences & Technologies), CEA Life Sciences Department
- Laboratoire de Chimie des Surfaces et Interfaces (Laboratory of Surface and Interface Chemistry), lnstitut Rayonnement Matière de Saclay (IRAMIS, Saclay Matter Radiation Institute), CEA Matter Sciences Department
- Laboratoire d'Innovation pour les Technologies des Energies Nouvelles et les Nanomatériaux (LITEN, Laboratory for Innovation in New Energy Technologies and Nanomaterials), CEA Technological Research Department

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CEA - Vincent Artero Phone: +33 (0)4 38 78 91 06 - email: vincent.artero@cea.fr

Code brève
ADIT : 61852

ADIT - Jean-François Desessard - Email: jfd@adit.fr

eTech France numéro 236 (13/01/2010) - ADIT / ADIT - http://www.bulletins-electroniques.com/actualites/61852.htm