Supporting Information
Hierarchical Pd-Sn Alloy Nanosheet Dendrites: An Economical and Highly
Active Catalyst for Ethanol Electrooxidation
Liang-Xin Ding, An-Liang Wang, Yan-Nan Ou, Gao-Ren Li,* Qi Li, Rui Guo, Wen-Xia Zhao &
Ye-Xiang Tong
MOE Laboratory of Bioinorganic and Synthetic Chemistry, KLGHEI of Environment and Energy
Chemistry, School of Chemistry and Chemical Engineering, Instrumental Analysis & Research Center,
Sun Yat-sen University, Guangzhou 510275, P. R. China
Study of Electrochemical Formation of Pd-Sn alloys
f
25
j
i
j / mA cm
-2
gh
0
b
c
a
-25
(1)
(2)
(3)
d
e
-50
-75
-0.6
-0.3
0.0
0.3
0.6
E / V (vs. SCE)
Figure S1. CV curves of measured on Pt electrodes in solutions of (1) 0.005 M PdCl2+1.0 M HCl+0.01 M NH4Cl;
(2) 0.01 M SnCl2+1.0 M HCl+0.01 M NH4Cl, and (3) 0.01 M SnCl2+0.005 M PdCl2+1.0 M HCl+ 0.01 M NH4Cl.
The electrochemical formation of Pd-Sn alloys was investigated by cyclic voltammograms (CVs) in
solutions of (1) 0.005 M PdCl2+1.0 M HCl+0.01 M NH4Cl, (2) 0.01 M SnCl2+1.0 M HCl+0.01 M
1
NH4Cl, and (3) 0.01 M SnCl2+0.005 M PdCl2+1.0 M HCl+0.01 M NH4Cl. The cathodic reduction
wave a is seen at -0.2 V in Figure S1(1), and it corresponds to the electro-reduction of Pd2+→Pd. The
oxidation waves g and h correspond to desorption of hydrogen adsorbed in Pd deposits. The
oxidation wave i corresponds to the dissolution of Pd. Two reduction waves b and c at -0.45 V and
-0.55 V, respectively, are seen in Figure S1(2), and they correspond to the electro-reduction of Sn2+ to
Sn, indicating this electro-reduction process is carried out via two steps of Sn2+→Sn+ and Sn+→Sn.
The oxidation wave f corresponds to the dissolution of Sn. Two cathodic reduction waves d and e are
also observed at -0.36 and -0.52 V in Figure 1(3), respectively. The reduction wave d at -0.36 V can
be attributed to the overlap of cathodic reduction waves of Sn2+→Sn+ and Pd2+→Pd, and the
reduction wave e at -0.52 V corresponds to the electro-reduction of Sn+→Sn. However, the oxidation
wave of Sn is not observed in Figure S1(3) during positive scan, indicating almost no Sn is dissolved
because of the formation of Pd-Sn alloys. Compared with oxidation wave i, the oxidation wave j
shifts positively, and this can be attributed to the effct of Pd-Sn alloys. Based on the above CV results,
Pd-Sn alloys can be successfully fabricated in solution of 0.01 M SnCl2+0.005 M PdCl2+1.0 M
HCl+0.01 M NH4Cl by electrodeposition route when the deposition potential is negative to -0.6 V.
2
Intensity (a.u.)
200
100
20
*
30
*
40
50
3
SnO (121)
300
PdSn2 PdSn2(204)
PdSn2(311)
PdSn3(313)
(b)
*
PdSn3(220)
PdSn3(200)
PdSn3(202)
PdSn3(210)
PdSn3(121)
PdSn3(004)
(a)
2.5 μm
* Substrate
*
*
0
2 Theta (degree)
60
Figure S2. (a) EDS and (b) XRD patterns of Pd-Sn ANSDs.
20000
50000
485.0 eV
486.9 eV
8.5 eV
Sn 3d5/2
30000
8.5 eV
493.4 eV
60000
(b)
495.3 eV
70000
Sn 3d3/2
335.55 eV
80000
Pd 3d5/2
40000
340.80 eV
(a)
5.25 eV
Count/s
Count/s
50000
Pd 3d3/2
60000
40000
30000
10000
20000
348
345
342
339
336
333
330
498 496 494 492 490 488 486 484 482
Binding Energy (eV)
Binding Energy (eV)
Figure S3. XPS patterns of (a) Pd 3d and (b) Sn 3d in Pd-Sn ANSDs.
4
(b)
(a)
(c)
Figure S4. SEM images of Pd-Sn deposits prepared in 0.02 M SnCl2+0.0025 M PdCl2+0.01 M C 6 H 11 O 7 Na+3.0 M
HCl at current density of 2.0 mA/cm2 for 60 min at (a) 90 0C, (b) 60 0C, and (c) 25 0C.
5
(a)
(b)
Figure S5. SEM images of Pd-Sn ANPs with different magnifications: (a) 5000×; (b) 25000×.
j / mA mg
80
(mA mg
100
-1
Pd
-1
Mass current
120
1.2
)
(a)
(b)
Pd
140
0.9
0.6
0.3
60
0
200
400
600
800
t/s
40
20
0
0
200
400
600
800
t/s
Figure S6. Chronoamperometry curves of various Pt samples recorded in solution of 1.0 M C2H5OH+1.0 M KOH
at a constant potential of -0.2 V for 800 s: (a) Pd-Sn ANSDs; (b) Pd-Sn ANPs.
6
2 μm
Figure S7. SEM image of Pd-Sn ANPDs-1 prepared in 0.01 M SnCl2+0.003 M PdCl2+ 0.02 M NH4Cl at 2.0
mA/cm2 at room temperature for 60 min.
2 μm
Figure S8. SEM image of Pd-Sn ANPDs-2 prepared in 0.01 M SnCl2+0.003 M PdCl2+ 0.05 M NH4Cl at 1.0 mA/cm2
at room temperature for 60 min.
7