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 Au0.18Ag0.82. 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.