Prominent electrocatalytic methanol oxidation from cauli-flower shape gold with high-index facets

Nano-sized gold has been recognized as a potential catalyst in methanol fuel cells for both low cost and no formation of poisoning species compared with Pt. Previous techniques to prepare highly effective pure gold catalysts for methanol fuel cells are dealloying, which needs stern conditions. In this paper, cauli-flower shape gold nanoparticles with exposed high-index facets were obtained by a mild hydrothermal method. During the reaction process, sodium dodecyl sulfonate selectively protected high-index facets of gold, and H2O2 kept etching low-index ones and growing new ones at the same time. A possible growth mechanism for high-index facets was proposed. The as-prepared gold nanoparticles were employed as electrocatalysts in the methanol oxidation. The results show enhanced anode current of 1249.8 μA cm−2 at 0.18 V in solutions with 0.5 M KOH and 1.0 M CH3OH, which is 10.68-fold larger than the previous reported value based on nanoporous gold catalysts. The preparation method of cauli-flower shape gold was easy to be operated and controlled, which is also universal in the synthesis of other materials with high-index facets.