Octahedral Noble‐Metal Nanoparticles and Their Electrocatalytic Properties

Abstract

Octahedrally shaped noble-metal nanocrystals are fascinating for their unique properties, such as electrocatalytic, catalytic, plasmonic, and optical behavior, owing to their exclusively exposed {111} facets; Oh symmetric structure; and close-packed surface atoms in low-index surface categories, which are normally stable in a reaction. A series of protocols in the preparation of noble-metal nano-octahedra through a wet-chemical synthetic strategy have been developed in recent years. Herein, advances in synthetic approaches and mechanistic studies of noble-metal nano-octahedra are systematically discussed and key factors, including reduction kinetics, selective capping, and epitaxial growth, are outlined. Their unique performance as advanced electrocatalysts towards fuel-cell reactions is highlighted as well.

Solvothermal synthesis of metal nanocrystals and their applications

“…Octahedral shaped MNCs are fascinating nanoentities with unique catalytic behavior due to their exclusively exposed {1 1 1} facets; O h symmetric structure; and closepacked surface atoms in low-index surface categories, which are highly stable under reaction condition [158]. An investigation on Pt 3 Ni single crystal with different low-index surfaces has distinctly elucidated that the activity of ORR on Pt 3 Ni {1 1 1} is remarkably higher than that on Pt 3 Ni {1 1 0} and Pt 3 Ni {1 0 0}.…”

Fe3O4/PANI/m-SiO2 as robust reactive catalyst supports for noble metal nanoparticles with improved stability and recyclability

“…Noble metal nanoparticles with high surface areas have been well recognized as promising nanocatalysts for liquid or gaseous reactions. [1][2][3][4] Therefore, much attention has been paid to the rational design and synthesis of noble metal nanoparticles with controllable size [5][6][7] and specic shape [8][9][10][11][12][13][14][15][16] due to their determining roles in catalytic activity. Although their obvious advantages of simple separation, reusability, and catalytic selectivity have been evidenced when compared with homogeneous catalysts, 17,18 unsupported nanocatalysts tend to coagulate and therefore lose their initial catalytic activity and selectivity due to their high surface energies.…”

Effect of Nanoparticle Shape on the Oxygen Reduction Reaction Activity of PtNiFe Nanocatalysts

“…The HR-TEM image (Figure b) clearly displays the lattice constant (∼0.22 nm), which is close to that of the (111) facet of the Pt-based alloy. ,,, When the morphologies are oriented along [110], [001], and [111], the PtNiFe octahedra exhibit rhombic, square, and hexagonal projections, respectively (Figure S2). − Also, Figure c exhibits a large area of PtNiFe nanocubes with an average size of 12.29 ± 1.52 nm (Figure S3). Generally, the nanocrystals are all uniform and exclusively bound by well-defined (200) facets with the spacing distance of 0.19 nm (Figure d). ,,,, Further, the polyhedral shape had an average size of 10.03 ± 1.22 nm (Figure S4) and can be identified by the hexagonal projections, as observed in Figure e.…”