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 K2PtCl4 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.