Elecnano⁴ - 7^th ECHEMS

Functional catalysts for hydrogen production and uptake, and oxygen reduction based on modified carbon nanotubes networks 

Le Goff, A.1; Artero, V.2; Jousselme, B.1; Morozan, A.1 ; Dinh, P. T.2; Guillet, N.3; Métayé, R.1; Fihri, A.2; Palacin, S.1; Fontecave, M2

Chimie des Surfaces et Interfaces, DSM/CEA Saclay; serge.palacin@cea.fr
2 Chimie et Biologie des Métaux, DSV/CEA Grenoble
3 Technologies de l'Hydrogène, LITEN/CEA Grenoble

Interconversion of water and hydrogen in unitized regenerative fuel cells is a promising energy storage framework for smoothing out the temporal fluctuations of solar and wind power.
However, replacing currently used platinum catalysts by lower-cost and more abundant materials is a pre-requisite for this technology to become economically viable.
We recently showed that the covalent grafting of a nickel bisdiphosphine–based mimic of the active site of hydrogenase enzymes onto multiwalled carbon nanotubes results in a high–surface area cathode material with high catalytic activity, even under the strongly acidic conditions required in classical proton exchange membranes. Hydrogen evolves from aqueous sulfuric acid solution with very low overvoltages (20 millivolts), and the catalyst exhibits exceptional stability (more than 100,000 turnovers).
The same catalyst is also very efficient for hydrogen oxidation in this environment, exhibiting current densities similar to those observed for hydrogenase-based materials
Besides, similar carbon nanotubes networks are used as host matrix for various metallo-organic catalysts able to reduce oxygen.

1 Le Goff, A.; Artero, V.; Jousselme, B.; Dinh, P. T.; Guillet, N.; Métayé, R.; Fihri, A.; Palacin, S.; Fontecave, M.; 2009, Science, 326, 1384-1387.
2 Le Goff, A.; Artero, V.; Métayé, R.; Moggia, F.; Jousselme, B.; Razavet, M.; Ding, P. T.; Palacin, S.; Fontecave, M. ;  Int. J. Hydrogen Energy 2010, in press (doi:10.1016/j.ijhydene.2010.02.112).
3 LeGoff, A.; Moggia, F.; Debou, N.; Jegou, P.; Artero, V.; Fontecave, M.; Jousselme, B.; Palacin, S. ;  J. Electroanal. Chem 2010, 641, 57.
4. Morozan, A.; Jousselme, B.; Palacin, S.; Energy and Environmental Science 2011, 4, 1238.
5. Morozan, A.; Campidelli, S.; Filoramo, A.; Jousselme, B.; Palacin, S.; to be published.