Single Nanocrystals of Platinum Prepared by Partial Dissolution of Au-Pt Nanoalloys

Abstract

Small metal nanoparticles that are also highly crystalline have the potential for showing enhanced catalytic activity. We describe the preparation of single nanocrystals of platinum that are 2 to 3 nanometers in diameter. These particles were generated and immobilized on spherical polyelectrolyte brushes consisting of a polystyrene core (diameter of approximately 100 nanometers) onto which long chains of a cationic polyelectrolyte were affixed. In a first step, a nanoalloy of gold and platinum (a solid solution) was generated within the layer of cationic polyelectrolyte chains. In a second step, the gold was slowly and selectively dissolved by cyanide ions in the presence of oxygen. Cryogenic transmission electron microscopy, wide-angle x-ray scattering, and high-resolution transmission electron microscopy showed that the resulting platinum nanoparticles are faceted single crystals that remain embedded in the polyelectrolyte-chain layer. The composite systems of the core particles and the platinum single nanocrystals exhibit an excellent colloidal stability, as well as high catalytic activity in hydrogenation reactions in the aqueous phase.

A simple electrochemical method for conversion of Pt wires to Pt concave icosahedra and nanocubes on carbon paper for electrocatalytic hydrogen evolution

“…2d) of a single Pt concave nanocube presents the lattice fringes with interplanar spacing of 0.196 nm along the [100] zone axis (Fig. 2d, inset), corresponding to the (200) plane of fcc Pt [15]. A HAADF-STEM image shows the shape of typical Pt concave nanocube with the exposed (200) plane (Fig.…”

“…The catalytic performance of noble metal nanocrystals is highly dependent on their size, shape, composition, crystal facet, crystal phase, etc. Besides the recently developed crystal-phase controlled synthesis of noble metal nanocrystals [8][9][10][11][12][13], lots of efforts have been devoted into the shape-controlled synthesis of noble metal nanostructures with high-index facets [14][15][16][17][18][19][20][21][22]. However, most of the reported noble metal nanostructures with unique morphologies are prepared via the traditional wet-chemical methods in which metal salts or complexes are used as precursors, and surfactants or ligands are used to tune/ stabilize their morphologies [23][24][25][26][27].…”

Effect of preparation temperature and ions doping on size, morphology and catalytic activity of Co-B amorphous nano catalyst

“…Nanoparticles have potential applications in chemistry, physics, electronics, biology, and medicine due to their unique characteristics different from bulk materials. Metal nanoparticles have been attracting great attention because of their remarkable catalytic performance in hydrogenation, oxidation, and reduction reactions [1][2][3]. For example, transition metal nano clusters have been studied as catalysts in various organic and inorganic reactions [4].…”

Gold-platinum alloys and Vegard's law on the nanoscale

“…Nanoparticles (NPs) made of noble metals have proven to be excellent catalysts. [1][2][3][4][5][6][7][8] Alloy particles from gold (Au) and platinum (Pt) are of particular interest, as they show enhanced catalytic behavior in important oxidation reactions. [9][10][11][12][13][14][15][16][17] They allow these reactions to take place under mild conditions, thus offering hope for materials' synthesis with minimal ecological impact.…”