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

Abstract

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 m2 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.

Iodine Ions Mediated Formation of Monomorphic Single-Crystalline Platinum Nanoflowers

“…This type of nanocrystal growth, formation of initial multipod particles with tubers followed by autocatalytic growth, has previously been observed in the formation of hyperbranched Ag nanostructures 56 and Pt polycrystalline nanodendrites. 57 Following the above discussions, Figure 8 shows a possible schematic pathway to illustrate the formation of Pt singlecrystalline nanoflowers. When I − and PtCl 6 2-mixed together and injected into hot EG, PtI 6 2-was immediately produced.…”

Block-copolymer-assisted synthesis of hydroxyapatite nanoparticles with high surface area and uniform size

“…Although block copolymers such as P123 and F127 have been widely used as structure-directing agents for mesoporous materials, in our synthesis, F127 acts as a stabilizer rather than a structure-directing agent. Recently, nanoparticles synthesized using nonionic surfactants as a stabilizer have attracted much attention because the stabilizer can inhibit the aggregation of nanoparticles, providing an easy and reproducible route for generating a uniform particle size [21][22][23][24]. In addition, the high external surface area of nanoparticles is beneficial for biomedical applications such as intracellular drug delivery [25][26][27], cell bioimaging [28][29][30], and purification and adsorption of biological molecules [31].…”

Hydrothermal growth of cross-linked hyperbranched copper dendrites using copper oxalate complex

“…To enhance the performance of metals in particular application, they have been synthesized in a variety of superstructures such as wheellike [8], flower-like [9], hollow structures [10], mesoporous microstructures [11], etc. Among them, metal nanocrystals with highly branched nanostructures have drawn considerable attention owing to their unique physicochemical properties as well as great potential as catalysts, sensing materials, and building blocks for nanoscale devices [12][13][14][15][16][17][18][19][20][21]. Particularly, highly branched structures such as dendrites, which are observed in nonequilibrium growth process, have been found to exhibit extensively novel properties and relevant application [12][13][14][15][16][17][18][19][20][21].…”

“…Furthermore, dendritic superstructures are of particular importance in fundamental physics study and crystal growth understanding. Recently, the attention has been raised to the study of dendritic metal structures including Au [12][13][14], Ag [15], Pt [16,17], Pd [18,19], and even bimetallic structures [20,21]. To date, the synthesis of highly branched metal nanostructures is mainly based on electrochemical deposition and hydrothermal method in the presence of polymeric stabilizer or surfactant.…”