Figure S3 GC spectrum using FID-Methanator for the (a) commercial pure CO, and (b) evolved gas from FA/SF system over Pd/C synthesized with citric acid at ...
Pd/C Synthesized with Citric Acid: An Efficient Catalyst for Hydrogen Generation from Formic Acid/Sodium Formate —Supplementary Information Zhi-Li Wang, Jun-Min Yan*, Hong-Li Wang, Yun Ping, and Qing Jiang Key Laboratory of Automobile Materials, Ministry of Education, Department of Materials Science and Engineering, Jilin University, Changchun 130022, China
1
0.20
0.15
0.10
(b)
(1) (2) (3) (4)
Absorbance (a.u.)
0.25
0.05
0.00
350
400
450
500
550
600
Wavelength (nm) Figure S1 (a) Color evolution of Na2PdCl4 aqueous solution (4.70×10-3 M) after addition of (1) SF (0.84 M), (2) FA (1.06 M), and (3) citric acid (0.03 M) for the given time at room temperature. (b) UV-vis spectra for aqueous solution of (1) pure Na2PdCl4, (2) Na2PdCl4 with FA, (3) Na2PdCl4 with citric acid , and (4) Na2PdCl4 with SF for 2 min.
It can be seen From Fig. S1a(1) that, after addition of SF into Na2PdCl4 aqueous solution for 2 min, the solution color changes from yellow to black, and the corresponding UV-vis absorption peak of [PdCl4]2- at 415 nmS1 (Fig. S1b(1)) disappears (Fig. S1b(4)). This indicates that Pd2+ cations have been reduced to Pd NPs by SF within 2 min. However, FA or citric acid can not reduce Pd2+ which is proved by the unchanged solution color after addition of FA (Fig. S1a(2)) or citric acid even for 300 min (Fig. S1a(3)). Moreover, the characteristic UV-vis absorption of [PdCl4]2- does not disappear after addition of FA (Fig. S1b(2)) or citric acid (Fig. S1b(3)). Thus, in the present H2 generation system, SF acts as a useful reducing agent for in situ formation of Pd NPs.
2
H2 2.00E-009
1.00E-009
Intensity
CO2 Ar
H2 O 0.00E+000
0
8
16
24
32
40
48
m (z) Figure S2 MS spectrum for the evolved gas from FA/SF system over Pd/C synthesized with citric acid at 298 K under Ar atmosphere.
300000
CO
Intensity
150000
CO2
(a)
(b) 0
0
5
10
15
20
Time (min) Figure S3 GC spectrum using FID-Methanator for the (a) commercial pure CO, and (b) evolved gas from FA/SF system over Pd/C synthesized with citric acid at 298 K .
3
1200000
H2
Intensity
800000
400000
CO2 0
2
4
6
8
10
12
14
16
Time (min)
Figure S4 GC spectrum using TCD for the evolved gas from FA/SF over Pd/C synthesized with citric acid 298 K. 100
Volume of gas (mL)
80 60 40 20 0 0
50
100
150
200
250
300
Time (min) Figure S5 Gas generation by decomposition of FA/SF (1.06 M/0.84 M, 5 mL) in THF catalyzed by in situ prepared Pd/C catalyst (nPd/n(FA+SF)=0.005) with citric acid at 298 K.
4
Volume of the gas (mL)
100 80 60 40 20 0 0
50
100
150
200
250
300
Time (min) Figure S6 Gas generation from citric acid aqueous solution (1.06M, 5 mL) catalyzed by Pd/C (nPd/ncitric acid = 0.009) at 298K. 350 56%
Volume of gas (mL)
300 250 200 25%
150 0%
100 75%
50 0
100%
0
100
200
300
400
500
600
700
Time (min) Figure S7 Gas generation by decomposition of FA/SF with different FA molar percents (n(FA+SF) = 9.5 mmol) catalyzed by in situ prepared Pd/C with citric acid (nPd/n(FA+SF) = 0.005) at 298K.
5
6.00E-009
H2 Ar
Intensity
4.00E-009
2.00E-009
H2O 0.00E+000
0
8
16
24
32
40
48
m (z) Figure S8 MS spectrum for the evolved gas from SF aqueous solution (1.9 M, 5 mL) over Pd/C synthesized with citric acid (nPd/nSF=0.005) at 298 K under Ar atmosphere.
(a)
30
30
Frequency (%)
Frequency (%)
40
20
10
(b)
20
10
0
0 1
2
3
4
Size (nm)
5
6
6
7
8
9
10
11
12
13
14
15
size (nm)
Figure S9 Size distributions of Pd NPs prepared (a) with citric acid and (b) without citric acid.
6
35
2000
(a)
C (002)
400
Frequency (%)
800
25
Intensity (a. u.)
1200
(c)
30
Pd (111)
1600
Pd (200) Pd (220) Pd (311)
20 15 10 5
0
0
20
30
40
50
60
70
80
2
90
3
2 (degree)
4
Size (nm)
Figure S10 (a) XRD pattern and (b) TEM image, and (c) size distribution of Pd/C synthesized with citric acid after the catalytic reaction.
350
Volume of gas (mL)
300 250 st
200
1 nd 2 rd 3 th 4
150 100 50 0 0
100
200
300
400
500
600
700
800
Time (min) Figure S11 Recycle test of Pd/C synthesized with citric acid toward H2 generation from FA/SF with different run numbers.
7
Frequency (%)
30
(b)
20
10
0 3
4
5
6
7
8
9
10
Size (nm)
Figure S12 (a) TEM image and (b) size distribution of in situ synthesized Pd/C in the presence of L-ascorbic acid.
Frequency (%)
40
(b)
30
20
10
0 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
Size (nm)
Figure S13 (a) TEM image and (b) size distribution histograms of in situ synthesized Pd/C in the presence of PVP.
8
350 (a) (b) (c)
Volume of gas (mL)
300 250 200 150 100 50 0 0
100
200
300
400
Time (min) Figure S14 Gas generation by decomposition of FA/SF (1.06 M/0.84 M, 5 mL) catalyzed by Pd/C (nPd/n(FA+SF)=0.005) synthesized (a) with PVP, (b) with PVP after washing, and (c) with citric acid at 298 K.
Table S1 Conversion and TOF values for decomposition of FA/SF system catalyzed by various heterogeneous catalysts.
Catalyst
HCOOH+HCOONa
Tem.
CO
Reaction
H2 volume
ncatalyst
Conversion
TOF
Ref.
(mmol)
(K)
generation
time (min)
(mL)
(mmol)
(%)
(mol H2. mol catalyst-1. h-1)
PdAu/C-CeO2
49.7+16.65
365
Yes
AuPd/ED-MIL-101
120
625
0.113
39
113.1
24
3.04+1.02
363
Yes
65
73
0.026
74
106.0
29
Pd/C with citric acid
5.3+4.2
298
No
160
196
0.047
85
64.0
This work
PdAg/C-CeO2
49.7+16.65
365
Yes
120
210
0.113
13
38.0
24
PdAu@Au/C
33.2+33.2
365
Yes
360
712
0.227
44
21.4
27
Ag@Pd
10+0
293
No
240
100
0.200
41
5.1
28
Calculation methods: xa =
PatmVH 2 / RT n( FA SF )
(S1)
Where xa is conversion, Patm is the atmospheric pressure, VH 2 is the final generated volume of H2 gas, R is the universal gas constant, T is the room temperature (298 K), 9
n( FA SF ) is the total mole number of reactants of FA and SF. TOF =
PatmVH 2 / RT nPd t
(S2)
Where npd is the mole number of Pd catalyst and t is the reaction time in hour. Rm =
n( FA SF ) n FA
(S3)
Where the Rm is the theoretical molar ratio of H2 to CO2 based on equations (1) and (2), nFA is the mole number of FA.
References: S1. Lim, B., Jiang, M., Tao, J., Camargo, P. H. C., Zhu, Y. & Xia, Y. Shape-controlled synthesis of Pd nanocrystals in aqueous solutions. Adv. Funct. Mater. 19, 189-200 (2009).
10