One-step, template-free electrochemical preparation of three-dimensional porous Au nanowire network and its enhanced activity toward methanol electrooxidation

• Three-dimensional porous gold nanowire-networks (3D PGNs) were fabricated simply by electrodeposition.
• Cetyltrimethylammonium bromide (CTAB) was responsible for nanowire growth.
• Fine structures of 3D PGNs were tunable with CTAB concentrations and electrodeposition time.
• Optimized 3D PGN showed a better electrocatalytic activity to methanol oxidation than bulk gold.

Three-dimensional (3D) porous Au nanowire networks (PGNs) with large electrochemical active areas were fabricated by one-step, template-free electrodeposition involving cetyltrimethylammonium bromide (CTAB) as the stabilizer and HAuCl4 as the precursor. As-prepared 3D PGNs were characterized with scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), atomic force microscopy (AFM), energy dispersive X-ray spectroscopy (EDS), and electrochemical cyclic voltammetry. The results indicate all 3D PGNs were composed of Au nanowires and the fine structures of 3D PGNs (diameters and lengths of nanowires, and thicknesses of 3D PGNs) were controllable to some extent by adjusting CTAB concentration and electrodeposition time. CTAB concentration and electrodeposition time were allowed to be tuned over a certain range, beyond which 3D PGN cannot be produced. Additionally, the electrocatalytic activity was assessed by employing the 3D PGN with largest electrochemical active area as a representative. The optimized 3D PGN exhibited a better electrocatalytic activity toward methanol than bulk Au due to its unique nanostructure. Such 3G PGNs fabricated simply by electrodeposition may be directly used as catalyst and catalyst support or converted into composite catalyst by decorating other metal nanoparticles.

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