Supplementary Information
Scheme S1 The “deposition-redispersion” strategy used for the preparation of supported
Pd/SiO2 catalysts with clean surface of the metal nanocrystals.
-1-
Fig. S1 Size distributions of the cubic (a), octahedral (b) and spherical (c) Pd nanoparticles.
Approximately 120 particles were counted for each figure.
30
a
Size distribution /%
25
20
15
10
5
0
2
4
6
8 10 12 14 16 18 20 22 24 26
Particle size (diagonal) / nm
30
b
Size distribution / %
25
20
15
10
5
0
2
4
6
8
10 12 14 16 18 20 22 24 26
Particle size (verte to vertex) / nm
30
c
Size distribution / %
25
20
15
10
5
0
2
4
6
8
10 12 14 16 18 20 22 24 26
Particle size (diameter) / nm
-2-
Fig. S2 SAED patterns obtained from a single Pd nanocube (a) and Pd octahedron (b).
a
b
-3-
Fig. S3 SEM images of Pd cubes (a, b) and Pd octahedra (c).
a
b
c
-4-
Fig. S4 The Fourier transform infrared spectroscopy (FT-IR) of Pd (octahedron)/SiO2 at
different stages of the supporting procedure. PVP was used as the capping agent here,
which should be removed before the catalytic activity evaluation. The three characteristic
peaks of PVP at 1436, 1670 and 2930 cm-1 disappeared after the
“precipitation-redispersion” method, indicating an effective elimination of PVP.
Transmittance / a.u.
SiO2
1436 1670
PVP
2930
PVP + SiO2
Pd octahedra/ SiO2
1000
1500
2000
2500
3000
Wavenumber / cm
3500
-1
-5-
4000
Fig. S5 The corresponding Arrhenius plots for comparison of apparent activation energies for
CO oxidation reaction of the different as-synthesized Pd/SiO2 catalysts.
ln [Turnover Frequency] / s
-1
0
cube
octahedron
sphere
-1
-2
-3
-4
-5
-6
-7
-8
0.0016
0.0018
0.0020
0.0022
-1
0.0024
-1
Temperature / K
Table S1 Apparent activation energies based on the Arrhenius plots data and related data of
supported Pd catalysts.
Pd catalysta
actual loadingb /
wt%
surface atom
ratioc
dispersiond
TOFe/ s-1
Ea/ kJ mol-1
cube
octahedron
sphere
2.91
2.94
2.89
0.15
0.12
0.38
0.68
0.61
0.72
0.52
0.69
0.19
76.5
52.9
42.6
a Loaded
on fumed silica. b Elemental analyses determined by ICP-AES. c The approximate percentage of
the surface atoms to the overall bulk atoms. d Based on CO chemisorption isotherm. e Maximum TOF
measured for all the catalysts.
Note: Here the TOF values were calculated as the following equation (actual Pd loading, Pd
dispersion and surface atom ratio were all taken into account):
Fgas  CCO  X CO
TOF=
m Pd
 D S
M Pd
Where Fgas is the total molar flow rate, CCO is the concentration of CO in gas mixture, XCO
is the conversion of CO, mPd is the mass of Pd in the reactor bed, MPd is the Pd atom weight,
D is the Pd dispersion obtained from the CO chemisorption, S is the percentage of surface
atoms to the overall bulk atoms (or surface atom ratio), which was calculated based on the
shape and size of the Pd nanocrystals in our experiments.
-6-
Fig. S6 TEM images of the Pd nanospheres with the average size of 3.9 nm (A, a), 7.5
nm (B, b) and 9.6 nm (C, c).
A
a
B
b
C
c
-7-
Fig S7 Size distributions of the Pd nanospheres with the size of 3.9 nm (a), 7.5 nm (b),
9.6 (c) nm. Approximately 120 particles were counted for each figure.
a
Size distribution / %
30
size=3.9 nm
25
20
15
10
5
0
2
4
6
8
10
12
14
Particle size / nm
18
size=7.5 nm
b
Size distribution / %
15
12
9
6
3
0
2
6
8
10
Particle size / nm
12
14
c
size= 9.6 nm
15
Size distribution / %
4
12
9
6
3
0
2
4
6
8
10
12
14
Particle size / nm
-8-
Fig. S8 The CO oxidation activities over the Pd (sphere)/SiO2 catalysts with the
average size of 3.9 nm, 7.5 nm and 9.6 nm. The CO oxidation activity were evaluated
in a packed-bed flow reactor using 50 mg of catalyst (40–60 mesh size) in a gas
mixture of 1.0 % CO, 1.0 % O2 in 98 % N2 at a flow rate of 97.2 mL min-1 and a
space velocity of 32.4 mL s-1 g-1.
100
Conversion / %
80
3.9 nm
7.5 nm
9.6 nm
60
40
20
0
50
100
150
200
250
300
o
Temperature / C
Fig. S9 The DRIFT spectra of CO adsorption on Pd (cube)/SiO2 under different
temperatures.
Intensity / a.u.
1878
1932
o
350 C
o
250 C
o
30 C
1940
2200
2100
2000
1900
Wavenumber/ cm
1800
-1
-9-
1700