Supporting Information
Polypyrrole Functionalized PtPd Electrocatalysts with High Performance
via the Formation of PtPd/PPy/PtPd Three-Layered Nanotube Arrays for
Electrooxidation of Small Organic Molecules
Han Xu,† Liang-Xin Ding,† Ye-Xiang Tong, and Gao-Ren Li*
MOE Laboratory of Bioinorganic and Synthetic Chemistry, KLGHEI of Environment and Energy
Chemistry, School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou
510275, China
†
These authors contributed equally to this work
5 nm
Figure S1. HRTEM image of PPy layer in the marked green area in Figure 3c.
1
Figure S2. SEM image of PtPd nanotube arrays (NTAs).
2
PtPd/PPy/PtPd TNTAs
PtPd/PPy/PtPd films
(a)
1.0
Specific Current/mA cm-2
Specific Current/mA cm-2
2.0
1.2
(b)
PtPd/PPy/PtPd TNTAs
PtPd/PPy/PtPd films
1.5
0.8
0.6
0.4
@0.55V(vsSCE)
1.0
0.2
0.0
0.5
-0.2
-0.4
-0.6
0.0
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
500
Potential/ V
1000
1500
2000
2500
3000
Time/sec
(c)
0.92
Specific Current/ mA cm-2
0.69
0.46
PtPd/PPy/PtPd TNTAs
0.23
(d)
0.33
0.22
0.11
PtPd/PPy/PtPd films
0.00
0
100
200
300
400
500
Cycle Number
Figure S3. (a) CVs of PtPd/PPy/PtPd TNTAs and PtPd/PPy/PtPd films in solution of 0.5 M CH3OH+0.5 M
H2SO4 at 100 mV/s; (b) Chronoamperometry curves of PtPd/PPy/PtPd TNTAs and PtPd/PPy/PtPd films in
solution of 0.5 M CH3OH + 0.5 M H2SO4 at 100 mV/s; (c) The change of peak current density with increasing
cycle number for PtPd/PPy/PtPd TNTAs and PtPd/PPy/PtPd films.
3
The electrocatalytic activity of PtPd/PPy/PtPd TNTAs towards methanol oxidation along with PtPd/
PPy/PtPd films was studied in solution of 0.5 M CH3OH+0.5 M H2SO4, and the CVs at 100 mV/s are
shown in Figure S3a, which shows the specific electroactivity of PtPd/PPy/PtPd TNTAs is ~2.7 times
higher than that of PtPd/PPy/PtPd films. The chronoamperometry curves of PtPd/PP/PtPd TNTAs and
PtPd/PPy/PtPd films were also measured in solution of 0.5 M CH3OH + 0.5 M H2SO4 as shown in
Figure S3b. Compared with PtPd/PPy/PtPd films, it is obvious that the PtPd/ PPy/PtPd TNTAs exhibit
a much higher current density over time and a much slower attenuation, indicating a much higher
catalytic activity for methanol electrooxidation and a much higher tolerance to carbonaceous species
generated during methanol electrooxidation. In addition, the PtPd/PPy/PtPd TNTAs also show higher
durability than PtPd/PPy/PtPd films as shown in Figure S3c.
4
PtPd/PPy/PtPd TNTAs
PtPd/PPy/PtPd films
(a)
-0.2
0.0
0.2
0.4
0.6
0.8
Specific Current/mA cm-2
Specific Current/mA cm-2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
-0.2
-0.4
1.0
(b)
1.5
PtPd/PPy/PtPd TNTAs
PtPd/PPy/PtPd films
@0.20V(vs SCE)
1.0
0.5
0.0
500
1000
1500
2000
2500
3000
Time/sec
Potential/ V
(c)
1.62
Specific Current/ mA cm-2
1.44
1.26
PtPd/PPy/PtPd TNTAs
1.08
(d)
0.76
PtPd/PPy/PtPd films
0.57
0.38
0.19
0
50
100
150
200
250
Cycle Number
Figure S4. (a) CVs of PtPd/PPy/PtPd TNTAs and PtPd/PPy/PtPd films in solution of 0.5 M HCOOH+0.5 M
H2SO4 at 100 mV/s; (b) Chronoamperometry curves of PtPd/PPy/PtPd TNTAs and PtPd/PPy/PtPd films in
solution of 0.5 M HCOOH+0.5 M H2SO4 at 100 mV/s; (c) The change of peak current density with increasing
cycle number for PtPd/PPy/PtPd TNTAs and PtPd/PPy/PtPd films.
5
3
(a)
2.5
(b)
2.0
2
1
PtPd/PPy/PtPd TNTAs
PtPd/PPy/PtPd films
@0.65V(vsSCE)
1.5
0
1.0
-1
PtPd/PPy/PtPd TNTAs
PtPd/PPy/PtPd films
-2
-3
-4
Specific Current/mA cm-2
Specific Current/mA cm-2
4
0.5
0.0
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
500
1000
1500
2000
2500
3000
Time/sec
Potential/ V
2.66
(c)
Specific Current/ mA cm-2
2.28
1.90
PtPd/PPy/PtPd TNTAs
1.52
0.85
(d)
0.68
0.51
PtPd/PPy/PtPd films
0.34
0
50
100
150
200
250
Cycle Number
Figure S5. (a) CVs of PtPd/PPy/PtPd TNTAs and PtPd/PPy/PtPd films in solution of 0.5 M CH3CH2OH +0.5 M
H2SO4 at 100 mV/s; (b) Chronoamperometry curves of PtPd/PPy/PtPd TNTAs and PtPd/PPy/PtPd films in
solution of 0.5 M CH3CH2OH +0.5 M H2SO4 at 100 mV/s; (c) The change of peak current density with increasing
cycle number for PtPd/PPy/PtPd TNTAs and PtPd/PPy/PtPd films.
6
2.0
(a)
(b)
-2
-2
1.0
1.5
0.6
Specific Current/mA cm
Specific Current/ mA cm
0.8
0.4
PtPd/PPy two-layered nanotube arrays
1.0
0.2
0.0
-0.2
PtPd/PPy/PtPd TNTAs
@0.55V(vsSCE)
0.5
PtPd/PPy/PtPd TNTAs
-0.4
PtPd/PPy two-layered nanotube arrays
-0.6
0.0
-0.2
0.0
0.2
0.4
0.6
0.8
500
1.0
1000
1500
2000
2500
3000
Time/sec
Potential/ V
(c)
0.92
-2
0.69
Specific Current/ mA cm
0.46
PtPd/PPy/PtPd TNTAs
0.23
(d)
0.54
0.36
PtPd/PPy two-layered nanotube arrays
0.18
0.00
0
100
200
300
400
500
Cycle Number
Figure S6. (a) CVs of PtPd/PPy/PtPd TNTAs and PtPd/PPy two-layered nanotube arrays in solution of 0.5 M
CH3OH+0.5 M H2SO4 at 100 mV/s; (b) Chronoamperometry curves of PtPd/PPy/PtPd TNTAs and PtPd/PPy
two- layered nanotube arrays in solution of 0.5 M CH3OH+0.5 M H2SO4 at 100 mV/s; (c) The change of peak
current density with increasing cycle number for PtPd/PPy/PtPd TNTAs and PtPd/PPy two-layered nanotube
arrays.
7
PtPd/PPy/PtPd TNTAs
(a)
1.8
PtPd/PPy two-layered nanotube arrays
Specific Current/mA cm
1.6
1.4
1.2
1.0
Specific Current/mA cm-2
-2
2.0
(b)
1.5
PtPd/PPy/PtPd TNTAs
PtPd/PPy two-layered nanotube arrays
@0.20V(vs SCE)
1.0
0.8
0.6
0.4
0.5
0.2
0.0
-0.2
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
0.0
1.0
Potential/ V
500
1000
1500
2000
2500
3000
Time/sec
(c)
1.62
-2
1.44
1.26
Specific Current/ mA cm
PtPd/PPy/PtPd TNTAs
1.08
1.25
(d)
PtPd/PPy two-layered nanotube arrays
1.00
0.75
0.50
0
50
100
150
200
250
Cycle Number
Figure S7. (a) CVs of PtPd/PPy/PtPd TNTAs and PtPd/PPy two-layered nanotube arrays in solution of 0.5 M
HCOOH+0.5 M H2SO4 at 100 mV/s; (b) Chronoamperometry curves of PtPd/PPy/PtPd TNTAs and PtPd/PPy
two-layered nanotube arrays in solution of 0.5 M HCOOH+0.5 M H2SO4 at 100 mV/s; (c) The change of peak
current density with increasing cycle number for PtPd/PPy/PtPd TNTAs and PtPd/PPy two-layered nanotube
arrays.
8
4
(a)
-2
-2
3
2.5
(b)
2.0
1
Specific Current/mA cm
Specific Current/mA cm
2
0
PtPd/PPy two-layered nanotube arrays
1.5
-1
-2
PtPd/PPy/PtPd TNTAs
@0.65V(vsSCE)
1.0
-3
-4
PtPd/PPy/PtPd TNTAs
-5
PtPd/PPy two-layered nanotube arrays
0.5
-6
0.0
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
500
1000
1500
2000
2500
3000
Time/sec
Potential/ V
2.66
(c)
-2
2.28
Specific Current/ mA cm
1.90
PtPd/PPy/PtPd TNTAs
1.52
(d)
1.740
1.653
1.566
PtPd/PPy two-layered nanotube arrays
1.479
0
50
100
150
200
250
Cycle Number
Figure S8. (a) CVs of PtPd/PPy/PtPd TNTAs and PtPd/PPy two-layered nanotube arrays in solution of 0.5 M
CH3CH2OH +0.5 M H2SO4 at 100 mV/s; (b) Chronoamperometry curves of PtPd/PPy/PtPd TNTAs and PtPd/PPy
two-layered nanotube arrays in solution of 0.5 M CH3CH2OH +0.5 M H2SO4 at 100 mV/s; (c) The change of peak
current density with increasing cycle number for PtPd/PPy/PtPd TNTAs and PtPd/PPy two-layered nanotube
arrays.
9