Rapid and Efficient Synthesis of Platinum Nanodendrites with High Surface Area by Chemical Reduction with Formic Acid

Platinum nanoarchitectures consisting of a large number of edges and corner atoms are highly favorable for enhancing the catalytic performance and efficient utilization of platinum materials. In a recent study, we have shown that Pluronic F127 triblock copolymer can assist the formation of dendritic platinum nanoparticles (Wang, L.; Yamauchi, Y. J. Am. Chem. Soc. 2009, 131,9152-9153). Herein, we expand this concept to produce platinum nanodendrites (PNDs) with interconnected arms by using various types of nonionic organic molecules. The PDNs with complex nanoarchitectures are produced simply by sonicating treatment of an aqueous solution containing K2PtCl4 precursor and formic acid in the presence of nonionic organic molecules without the need for any template, seed-mediated growth, and additive. As-produced PDNs were shown to be active as nanoelectrocatalysts for electro-oxidation formic acid. The investigated nonionic organic molecules include nonionic surfactants, e.g., Pluronic F127, Brij 700, Tetronic 1107, and polymer, e.g., poly(vinyl pyrrolidone) (PVP) and poly(1-vinylpyrrolidone-co-vinyl acetate) (PVP-co-VA). The typical PNDs produced with Pluronic F127 possess platinum atomic crystalline state with large domains and show high surface area (32 m(2) g(-1)). The proposed approach is highly favorable for facilitating the producing of PNDs in a wide range of platinum precursor concentrations. Because of its high flexibility and simple implement, the proposed approach can be considered as a very general and powerful strategy for producing PNDs with high surface area and open dendritic nanostructures for commercial devices. Furthermore, the dual roles of formic acid in synthesis of PNDs, i.e., reducing agent and structure-directing agent, are tentatively proposed based on the investigation results.