Electron conductive and proton permeable vertically aligned carbon nanotube membranes.

We report the fabrication of membranes hundreds of micrometers thick that demonstrate efficient electron conduction and proton transport through vertically aligned arrays of multiwalled carbon nanotubes (NTs) impregnated by epoxy. Electrical transport was Ohmic with a conductivity of 495 mS cm(-1). Protons traversed the membrane through the NT bore with a current of 5.