Template-Free and Direct Electrochemical Deposition of Hierarchical Dendritic Gold Microstructures: Growth and Their Multiple Applications

Hierarchical dendritic gold microstrutures (HDGMs) with secondary and tertiary branches are directlyelectrodeposited on an indium tin oxide (ITO) substrate without the use of any templates, surfactants, orstabilizers. The effects of electrodeposition potential and HAuCl4 concentration on the formation of HDGMsand time-dependent morphological evolution are investigated in detail. A diffusion-limited aggregation (DLA)mechanism is used to explain the formation of HDGMs. Typically, the as-synthesized HDGMs exhibitedmuch higher electrocatalytic activity and enhanced stability toward ethanol electrooxidation compared tobulk gold electrode and also display great Raman enhancement activity with the detection limit of 10 12Mfor rhodamine 6G. The surface of HDGMs possesses hydrophobicity even without modification with low-surface-energy coatings and has a remarkable superhydrophobic property even in corrosive solutions over awide pH range after the treatment with n-dodecanethiol. In addition, (super)oleophobicity is successfullyobtained by modification with 1H,1H,2H,2H-perfluorodecanethiol.