Iron(III) ion-supported electrosynthesis of urchin-like gold arrays

•Well-defined urchin-like Au arrays were facilely prepared by one-step electrodeposition.•Iron(III) ions serve as catalysts and growth directing agents.•This approach is simple, controllable and convenient, without any template, seed or surfactant.•The Au nanocrystals display high electrocatalytic activity toward the oxidation of ethylene glycol and glycerol.

In this study, well-defined urchin-like gold arrays were prepared on glassy carbon electrodes by one-step electrodeposition at the potential of 0.2 V for 600 s in the electrolyte containing 3.5 mM HAuCl4, 100 mM FeCl3 and 0.5 M HCl, preferentially growing along the (1 1 1) directions with high purity. Their growth mechanism were discussed in some detail, by investigating the control experiments such as the concentration of FeCl3 and HAuCl4, applied potential and electrodeposition time. It is found that iron(III) ions (mainly existed in the form of FeCl4−) here serve as catalysts and growth directing agents. The as-prepared Au nanocrystals display high electrochemically active surface areas toward the electrooxidation of ethylene glycol and glycerol. This approach is simple, controllable and convenient, whereas no additional seed, template, and surfactant are involved.

Graphical abstractIn this work, a simple, controllable and convenient method was developed for the preparation of well-defined urchin-like Au arrays by one-step electrodeposition, without any template, seed and surfactant, using iron(III) ions as catalysts and growth directing agents. The as-prepared Au nanocrystals display high electrocatalytic activity toward the oxidation of ethylene glycol and glycerol.Figure optionsDownload full-size imageDownload as PowerPoint slide