Synthesis of Bimetallic Au@Pt Nanoparticles with Au Core and Nanostructured Pt Shell toward Highly Active Electrocatalysts

Abstract

Au@Pt nanocolloids with nanostructured dendritic Pt shells are successfully synthesized by chemically reducing both H 2 PtCl 6 and HAuCl 4 species in the presence of a low-concentration surfactant solution. By applying an ultrasonic treatment, the particle size of the Au@Pt nanocolloids is dramatically decreased and their size distribution becomes very narrow. The difference in reduction potentials of the two soluble metal salts (Au(III) and Pt(IV) species) plays a key role in the one-step synthesis of the core-shell structure. Because of the different reduction potentials, the reduction of Au ions preferentially occurs over a short time to form the Au seeds. It is followed by overgrowth of Pt nanodendritic nanowires on the Au seeds, which is confirmed by ultraviolet-visible light absorption spectroscopy and transmission electron microscopy. Interestingly, the Pt shell thicknesses on Au cores can be easily tuned by controlling the Pt/Au molar ratios in the starting precursor solutions. Through the optimization of the Pt shell thicknesses, the Au@Pt nanocolloids can exhibit enhanced activity as an electrocatalyst for a methanol oxidation reaction, which will be important to improve the utilization efficiency of Pt catalysts in the future.

Layer-by-layer Nanoarchitectonics: Invention, Innovation, and Evolution

“…318,319 AuPt nanospheres with a Au metal core coated with a dendritic Pt shell were synthesized by adding ascorbic acid solution as a mild reducing agent to the precursor solution containing Au and Pt salts and Pluronic F127. 320,321 Because of the different reduction potentials of Au and Pt species, the reduction of Au ions preferentially occurs over a short time to form Au seeds. This is followed by overgrowth of Pt nanodendritic shell on the Au seeds.…”

Promotion Effect of Platinum on Gold’s Reactivity: A High-Resolution Photoelectron Spectroscopy Study

“…In this sense, the main reactions for which these catalysts have been tested are mainly oxygen reduction 2 and hydrogen 3 , methanol 4 , ethanol 5 or glycerol 6 oxidation. Whether the material is used as an anode or cathode in a fuel cell, the main concern is the high Pt content of these materials.…”

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].…”