Tuning Surface Structure of 3D Nanoporous Gold by Surfactant-Free Electrochemical Potential Cycling

3D dealloyed nanoporous metals have emerged as a new class of catalysts for various chemical and electrochemical reactions. Similar to other heterogeneous catalysts, the surface atomic structure of the nanoporous metal catalysts plays a crucial role in catalytic activity and selectivity. Through surfactant-assisted bottom-up synthesis, the surface-structure modification has been successfully realized in low-dimensional particulate catalysts. However, the surface modification by top-down dealloying has not been well explored for nanoporous metal catalysts. Here, a surfactant-free approach to tailor the surface structure of nanoporous gold by surface relaxation via electrochemical redox cycling is reported. By controlling the scan rates, nanoporous gold with abundant {111} facets or {100} facets can be designed and fabricated with dramatically improved electrocatalysis toward the ethanol oxidation reaction.

A surfactant-free potential-cycling approach is developed to tailor the surface structure of 3D nanoporous gold with an abundance of {111} or {100} facets by controlling the scan rates. The {111}-rich sample exhibits dramatically improved electrocatalysis toward the ethanol oxidation reaction in comparison with as-dealloyed conventional nanoporous gold.

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