On the Role of Ascorbic Acid in the Synthesis of Single-Crystal Hyperbranched Platinum Nanostructures

In this paper, a very simple and efficient wet chemical route is proposed to directly produce single-crystal hyperbranched platinum nanostructures (HPNSs), in high yield, within 10 min simply by sonication treatment of an aqueous solution containing K 2 PtCl 4 and ascorbic acid (AA) only. The results in this report demonstrate that even in the absence of any purposely added structure-directing agent and seed mediator, reaction kinetics of AA and the released byproduct derived from AA oxidation, that is, 2,3-diketo-l-gulonic acid (DGA), are capable of producing single-crystal HPNSs in aqueous medium. In addition to being a commonplace reducing agent (electron donor), AA plays a more important role relied on its byproduct, DGA, which serves as a shape-directing agent to direct the branched growth. The new insight into the role of AA in the synthesis of single-crystal HPNSs reported here provides a new viewpoint for further understanding the formation mechanism of anisotropic platinum nanostructures.