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. (C) 2013 Elsevier Ltd. All rights reserved.