Three-dimensional carbon nanotube–polypyrrole–[NiFe] hydrogenase electrodes for the efficient electrocatalytic oxidation of H2

Hydrogenase electrodes for hydrogen oxidation are elaborated by an innovative immobilization strategy of [NiFe] hydrogenases from Desulfovibrio fructosovorans on highly porous single-walled (SWCNT) and multi-walled (MWCNT) carbon nanotube electrodes. oelectrode fabrication involved the adsorption of hydrogenase and amphiphilic pyrrole monomer functionalized by a methylviologen moiety on the nanotube deposits. ectropolymerization of the adsorbed monomer then leads to the enzyme entrapment in polypyrrole film surrounding the nanotubes. In addition, the redox polypyrrole achieves an efficient electrical wiring of hydrogenase on SWCNT and MWCNT electrodes via a mediated electron transfer. The latter configuration showed improved performances in catalytic responses (up to 0.30 ± 0.01 mA cm−2) at stationary electrodes due to the more appropriate wettability of MWCNTs. This led to a better coating of the nanostructured surface and thus, to an enhanced mediated electron transfer between the enzyme and the nanotubes.