Structural analysis and shape-dependent catalytic activity of Au, Pt and Au/Pt nanoparticles

Abstract

Metallic nanoparticles of Au, Pt and Pt/Au have been synthesized using a chemical reduction approach. The structural characterization of these metallic nanoparticles has been carried out using conventional transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HR-TEM) techniques. HR-TEM images of Pt nanoparticles reveal their fcc-like structures, in the [103] and [011] orientations. However, in case of Au, the main structures are fcc-like and decahedral morphologies with five-fold symmetry axes. The structure of the gold nanoparticles was verified through their theoretically-simulated images, using a multislice approach of the dynamical theory of electron diffraction. These small particles have been used as electrocatalysts in Nafion membranes for fuel cell applications. The electrochemical characterization of the membranes shows that the Pt dispersion gives best performance for fuel cell applications.

On the Structural Origin of the Catalytic Properties of Inherently Strained Ultrasmall Decahedral Gold Nanoparticles

“…Furthermore, the strain will be largest at the support interface and therefore not easily accessible to incoming gas molecules. Gold nanoparticles in the size range of 2–10 nm are typically multiply twinned with the most stable forms being the non-space filling icosahedral and decahedral structures. − In the decahedral case, the particle is made up of five tetrahedra bound by (111) twin planes. As the angle between each (111) plane should be 70.53°, there is a missing angle of 7.35°, meaning such structures are crystallographically forbidden.…”

Effect of Multiply Twinned Ag(0) Nanoparticles on Photocatalytic Properties of TiO2 Nanosheets and TiO2 Nanostructured Thin Films

“…The two mirror regions are referred to as twin domains 1 and 2, respectively. Therefore, the Ag (0) NPs showed a strong tendency to form multiply twinned face-centered cubic superlattices with decahedral symmetry when their size was reduced to 10 nm ( Figure 5 f) [ 47 , 48 ].…”

Methanobactin‐mediated synthesis of bimetallic Au–Pd/Al 2 O 3 toward an efficient catalyst for glucose oxidation

“…The formation of twinned particles was very common for the transition metals with fcc crystal lattice when their size reduced to nanometre scale. Twinning often had a serious effect on the shape and symmetry of a nanocrystal, in particular, in the case of repeated twinning [31]. Compared with the lattice fringes of monometallic AuNPs (0.234 nm, Fig.…”