Controllable Synthesis of Metal Nanoparticles for Electrocatalytic Activity Enhancement - Atomically-Precise Methods for Synthesis of Solid Catalysts - page 230

d n 9 r 4 n g | 5

Figure 9.3 Representative TEM images of (a) the 3 nm , (b) the 5 nm truncated
cubic, and (c) the 7 nm cubic Pt NPs. The insets are the representative
HRTEM images of corresponding single particles, showing (a) Pt(111),
(b) Pt(100), and (c) Pt(100) lattice fringes. All scale bars in the insets
correspond to 1 nm.
Reprinted from ref. 22 with permission by Wiley-VCH.

.

Figure 9.4 TEM images of (a) FePt NPs and (b) FePt nanocubes.
Part (a) reprinted from ref. 6 with permission by the American Associ-
ation for the Advancement of Science. Part (b) reprinted from ref. 23 with
permission by American Chemical Society.

followed by a slow rate of heating slowed down the rate of nucleation and
growth. As a result, more Pt-atoms were allowed to grow on (111), forming
5 nm truncated cubes (Figure 9.3b) or 7 nm cubes (Figure 9.3c).
Using surfactant mediated growth, we have succeeded in preparing FePt
alloy NPs via thermal decomposition of Fe(CO) 5 and reduction of Pt(acac) 2
with size and shape controls. Monodisperse 6 nm FePt NPs were synthesized
by the simultaneous reduction of Pt(acac) 2 and decomposition of Fe(CO) 5 in
the presence of OA and OAm (Figure 9.4a). 6 By controlling the addition
sequence of OAm and OA as well as Fe(CO) 5 /Pt(acac) 2 ratio, 6.9 nm FePt
nanocubes were prepared (Figure 9.4b). 23

9.2.3.2 Anisotropic Growth in Reverse Micelle
Despite the examples demonstrated in shape-controlled synthesis of Pt-
based NPs, the growth along either h 100 i or h 111 i tends to yield NPs with