Nanoporous gold anode catalyst for direct borohydride fuel cell

Nanoporous gold (NPG) electrodes were fabricated in film and wire array formats by selectively dealloying Ag from Au_0.18Ag_0.82. Borohydride oxidation reaction (BOR) 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 that than observed at an Au disc and higher currents were realized. An onset potential of -1.07 V vs SCE which is 0.207 V lower than that at an Au disc was recorded. The oxidation current for 20 mM borohydride in 1 M NaOH increased to 73.6 mA cm^-2 from 3.17 mA cm^-2 at an Au disc. An n value of 7.49 was determined for the oxidation peak at high potential (-0.49 V) while a value of 4.26 was determined at low potential for the oxidation plateau centered at -0.05 V. NPG presents an attractive alternative to gold nanoparticle-based catalysts for use in direct borohydride fuel cells. NPG can establish intimate contact with an electrical substrate and eliminates the need for a carbon support.