Catalyst Combines Nanotubes And Nickel

By latching a nickel compound onto multiwalled carbon nanotubes, researchers in France have created a new catalytic material for proton-exchange membrane electrolyzers and fuel cells (Science 2009, 326, 1384). A team led by Vincent Artero and Marc Fontecave of Université Joseph Fourier and Serge Palacin of Commissariat á l’Energie Atomique developed the material, which catalyzes the reversible interconversion of water to hydrogen gas. This reaction could be capitalized on to use H₂ for storing energy generated from the electrolysis of water and to release energy via the reverse reaction. Most catalysts for this transformation use pricey platinum, so Artero and Palacin’s team decided to use a less expensive catalyst that mimics the nickel-based hydrogenase enzymes that nature uses to catalyze this reaction. By immobilizing their catalyst on nanotubes, the researchers were able to get it to work under aqueous conditions—a requirement for its practical use in proton-exchange membrane devices. The nanotube-catalyst material exhibits extreme stability, standing up to more than 100,000 turnovers for H₂ production and more than 35,000 turnovers for the reverse reaction.