Controlled Formation of Concave Tetrahedral/Trigonal Bipyramidal Palladium Nanocrystals

Abstract

Novel concave Pd nanocrystals with uniform diameter were successfully prepared in the presence of formaldehyde. While the outer surfaces of the as-prepared concave Pd nanocrystals are {111}, the faces concave toward the polyhedral center are high-surface-energy {110} faces. The degree of concavity and therefore the percentage of {110} of the nanocrystals are tunable by varying the amount of formaldehyde and the reaction temperature. Owing to the existence of active {110} facets, the electrocatalytic activity of the concave Pd nanocrystals displays dependency on their degree of concavity.

Small Adsorbate‐Assisted Shape Control of Pd and Pt Nanocrystals

“…[39] Interestingly, as shown in Figure 10a and 10b, the obtained Pd nanostructures were mainly concave tetrahedra. Both the selected area electron diffraction (SAED) and high resolution TEM (HRTEM) measurements clearly indicated that concave tetrahedra were single-crystalline.…”

“…[37,39,45,47,64,65] Studies from our group and others have clearly demonstrated that the strong adsorption of several adsorbates, like I − , CO and amines, could serve as an effective factor to enrich not only the surface structure but also the shape of Pd and Pt nanocrystals. In the following sections, several examples are used to discuss how different small adsorbates control the shape of Pd and Pt nanocrystals mainly from thermodynamic and kinetic aspects.…”

“…Both {111} and {110} are revealed in the concave tetrahedron and concave bipyramid. [39] 3. Common Strategies in the Shape-Controlled Synthesis of Noble Metal Nanocrystals Taken together, Section 2 tells that the surface together with the twinned boundaries/defects in nanocrystals of an fcc metal determines the morphology of the nanocrystals.…”

Ethylenediamine tetramethylene phosphonic acid assisted synthesis of palladium nanocubes and their electrocatalysis of formic acid oxidation

“…Pd nanocrystals with diverse morphologies have been synthesized, including wires [13], spheres [14], tubes [15], cubes [16], plates [17], rods [18][19][20], tetrahexahedra [21], cubooctahedra [22], octahedra [23], tetrahedra [24], and concave tetrahedra [25]. Among various shapes, {100}-enclosed Pd nanocubes are of particular interest in relation to formic acid oxidation because the {100} facet of Pd shows the highest catalytic activity among the three lowindex facets (Pd{100} > Pd{111} > Pd{110}) [26].…”

Preparation of Pd Nanoparticles with Tetrahedral, Spherical, Plate, and Feather Shapes by Capping with 1-Pentyl Isocyanide

“…Several groups have reported the morphologies and crystalline structures of metal nanoparticles [8][9][10][11][12][13][14][15][16][17][18][19][20][21]. Although Zheng et al reported the controlled formation of concave tetrahedral palladium nanoparticles [22], it is still challenging to control the morphologies of nanoparticles.…”