Simple Nanopowders For Electrolysis

A nickel-molybdenum catalyst to generate hydrogen from water can now be synthesized as a nanopowder, greatly improving its processability and allowing it to be studied in better detail (ACS Catal., DOI: 10.1021/cs300691m). James R. McKone, Harry B. Gray, and colleagues at Caltech prepared the Ni-Mo nanopowders in a two-step process, starting with an aqueous solution of nickel hexammine and ammonium molybdate. Heating the mixture in diethylene glycol produced a mixed Ni-Mo oxide precipitate, which was isolated and reduced with hydrogen to generate the Ni-Mo nanopowder. Scientists are developing nickel- or steel-based catalysts for the hydrogen evolution reaction because they are much cheaper than and nearly as active as traditional noble-metal electrocatalysts. The Caltech researchers found that the new powders can be suspended in solvents and, without a support material, be cast as layers onto electrode surfaces. Among other techniques, they used electron microscopy to determine that the catalyst material’s high porosity contributes to its activity.