Nanoporous gold catalyst for direct ammonia borane fuel cells

Nanoporous gold (NPG) electrodes were fabricated in film and wire array formats by selectively dealloying Ag from Au_0.18Ag_0.82. The ammonia borane (AB) oxidation reaction was studied by cyclic voltammetry at the NPG electrodes. The onset potential for the oxidation at NPG in a wire array format shifted to more negative potentials than that observed at a Au disc and higher currents were realised. An onset potential of -1.30 V vs. SCE was recorded which is 0.28 V lower than that at a Au disc. The oxidation current for 20 mM AB in 1 M NaOH increased from 2.65 mA cm^-2 at a Au disc to 13.1 mA cm^-2 at a NPG wire array. NPG is a viable candidate as an anode catalyst for a direct ammonia borane fuel cell.