1
Electronic Supporting Information
2
High activity and wide temperature window of Fe-Cu-SSZ-13 in the
3
selective catalytic reduction of NO with ammonia
4
5
Tao Zhanga, Jianmei Lia,†, Jian Liua,*, Daxi Wanga, Zhen Zhaoa,*, Junhua Lib,
6
Kai Chenga
7
a
102249, China
8
9
10
State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing,
b
State Key Joint Laboratory of Environment Simulation and Pollution Control, School of
Environment, Tsinghua University, Beijing, 100084, China
11
12
* Corresponding authors: Email address: zhenzhao@cup.edu.cn, liujian@cup.edu.cn
13
Postal Address: 18# Fuxue Road, Chang Ping District, Beijing, 102249, China,
14
Tel: 86-10-89731586, Fax: 86-10-69724721
15
†: This author has equal contribution as the first author.
16
17
18
19
20
21
22
23
24
25
26
27
1
FT-IR spectra of Cu-SSZ-13 and Fe-Cu-SSZ-13 samples are shown in Fig. S1. The spectra of all samples
2
exhibit similar structure characteristics. The vibrational band at 415 cm-1, which is Si-O bending modes,
3
can be observed in all amorphous SiO2 materials.1 The bands at 530 cm-1 and 463 cm-1 express the
4
vibration of TO4 units, and that at 640 cm-1 is attributed to the vibration of double six-membered oxygen
5
rings. In metal ion-exchanged zeolites, IR bands appear due to the perturbation of the T-O-T bond vibration
6
by the strong interaction between metal cations and the oxygen ions of the zeolite framework.2,3 The
7
asymmetric and symmetric T-O-T vibrations are observed at ~ 1040 and ~ 800 cm-1. The appearance of
8
band at 895 cm-1 is due to the perturbed asymmetric T-O-T structural vibrations in the vicinity of two
9
distinct Cu2+-occupied cationic positions.4 The band at 730 cm-1 is associated with an internal symmetric
10
framework vibration. The bands at 591 and 628 cm-1 are associated with Cu-O vibrations in bulk CuO,
11
those are not observed.5,6 The spectrum of Fe-Cu-SSZ-13 catalysts does not show the characteristic
12
framework band at 710-700 cm-1 suggesting extra-framework iron.7
15
16
17
18
19
20
21
22
415
463
530
640
730
b
a
1100
14
796
895
Absorbance / a.u.
c
1040
13
1000
900
800
700
600
Wavenumber / cm
500
400
-1
Fig. S1. FT-IR absorbance spectra of Cu-SSZ-13 (a); Fe-Cu-SSZ-13-1 (b); Fe-Cu-SSZ-13-2 (c).
1
2
3
4
5
6
7
8
9
Intensity / a.u.
57
Cu-SSZ-13-1
-1
100
80
60
40
20
0
-20
-40
10
Chemical shift / ppm
11
Fig. S2. 27Al MAS NMR spectrum of Cu-SSZ-13-1 sample.
12
13
14
15
16
17
18
19
20
21
22
1
H2-TPR measurements were performed to determine the types of metal species found in the different
2
catalysts. As shown in Fig. S3, in the low temperature range from 200 to 400 °C, Cu-SSZ-13 catalyst
3
shows two H2 consumption peaks, one is the reduction of isolated Cu2+ ions to Cu+ in the temperature range
4
of 180-300 °C and the other one is the reduction of CuO to Cu0 300-400 °C.8,9 A lower temperature for the
5
former redox peak meant more active copper species and higher NH3-SCR activity. The peak at high
6
temperatures (500-700 °C) was attributed to the reduction of highly stable Cu+ to Cu0 at the cation
7
exchange sites,10,11 and the Cu+ is formed from the reduction of isolated Cu2+ ions. Note that, if the
8
reduction experiments were stopped at 700 °C, the sample displayed the slight purplish color, indicating
9
the formation of a small amount of Cu0, although the majority of Cu+ is fully reduced at much higher
10
temperature. Furthermore, the catalyst with Cu+ to Cu0 reduction occurring at high temperature is expected
11
to produce more stable copper active species, which could be associated with a better NH3-SCR catalytic
12
performance at high temperatures.12
13
Hence, there are two types of Cu species in Cu-SSZ-13 catalyst, including external surface CuO and
14
isolated Cu2+ ions at the exchange sites, and the latter accounts for the majority of Cu species in Cu-SSZ-13
15
catalysts. However, no clear H2 consumption signal was detected for the Fe-Cu-SSZ-13 samples because
16
H2-TPR technique is not sensitive enough to detect the weak signal of the samples with low loading
17
amounts (Table 1).
18
H2 Comsumption (a.u.)
c
b
256
331
600
100
200
300
400
500
600
a
700
o
Temperature ( C)
19
20
Fig. S3. H2-TPR profiles of of Cu-SSZ-13 (a); Fe-Cu-SSZ-13-1 (b); Fe-Cu-SSZ-13-2 (c). “Dash line”
21
represents the fitting results.
22
1
2
3
4
5
6
7
8
9
Intensity / a.u.
10
Cu-SSZ-13-1
Fe-Cu-SSZ-13-2
Fe-Cu-SSZ-13-1
100
200
300
400
500
600
o
11
12
13
14
15
16
17
18
19
20
21
22
Temperature / C
Fig. S4. NH3-TPD curves of Cu-SSZ-13-1, Fe-Cu-SSZ-13-1 and Fe-Cu-SSZ-13-2.
1
2
3
4
5
6
7
8
9
10
Fig. S5 shows the reaction result of standard SCR at a high-space velocity (~ 800,000 h-1) over
Cu-SSZ-13-1 catalyst, and NO conversion ≤ 15 % is marked gray.
11
100
NO Conversion / %
80
Cu-SSZ-13-1
60
40
20
0
100
200
300
400
500
600
700
o
Temperature / C
12
13
Fig. S5. NO conversion versus reaction temperature for standard NH3-SCR over Cu-SSZ-13-1 sample. The
14
differential regime (NO conversion ≤ 15 %) is marked grey. Reaction mixture contains 1000 ppm NO, 1000
15
ppm NH3, 3 % O2. GHSV = 800,000 h-1.
16
17
18
19
20
21
22
1
2
3
4
5
6
7
8
9
10
As displayed in Fig. S6, Arrhenius plot is created by calculating NO turnover frequencies (TOF) on a per
mole of Cu basis using reaction data shown in Fig. S5.
ln (NO TOF) [mol NO/ mol Cu / s]
11
-3
b
-4
-5
Cu-SSZ-13-1, Ea ~ 47.9 KJ / mol
-6
1.8
2.0
2.2
-1
12
1000 / T (K )
13
14
Fig. S6. Arrhenius plots of NO conversion (in TOF, mol NO / mol Cu / s) over Cu-SSZ-13-1 catalyst. TOFs
15
were calculated using reaction data shown in Fig. S5. Reaction mixture contains 1000 ppm NO, 1000 ppm
16
NH3, 3 % O2 balanced with N2, at a GHSV = 800,000 h-1.
17
18
19
20
21
22
1
References
2
3
1. Jansen JC, van der Gaag FJ, van Bekkum H. Identification of ZSM-type and other 5-ring containing
4
5
6
7
8
zeolites by i.r. spectroscopy. Zeolites. 1984;4:369-372.
2. Sárkány J. Zeolite proton-assisted reoxidation of Cu0 in over-exchanged CuII-ZSM-5 reduced by
hydrogen. (1) Reoxidation in Ar stream: an FTIR study. Phys Chem Chem Phys. 1999;1:5251-5257.
3. Sobalík Z, Tvarůžková Z, Wichterlová B. Skeletal T-O-T vibrations as a tool for characterization of
divalent cation complexation in ferrierite. J Phys Chem B. 1998;102:1077-1085.
9
4. Sárkány J. Effects of water and ion-exchanged counterion on the FT-IR spectra of ZSM-5: Part III.
10
Cu+(CO)2-ZSM-5: interaction of Cu+(CO)2 complex with H2O and changes in skeletal T-O-T vibrations.
11
Appl Catal A Gen. 2002;229:291-312.
12
13
14
15
5. Lei GD, Adelman BJ, Sárkány J, Sachther WMH. Identification of copper(II) and copper(I) and their
interconversion in Cu/ZSM-5 De-NOx catalysts. Appl Catal B Environ. 1995;5:245-256.
6. Mohamed MM. Structural and acidic characteristics of Cu-Ni-modified acid-leached mordenites. J
Colloid Interf Sci. 2003;265:106-114.
16
7. Hammond C, Forde MM, Rahim MHA, Thetford A, He Q, Jenkins RL, Dimitratos N, Lopez-Sanchez JA,
17
Dummer NF, Murphy DM, Carley AF, Taylor SH, Willock DJ, Stangland EE, Kang J, Hagen H, Kiely CJ,
18
Hutchings GJ. Direct catalytic conversion of methane to methanol in an aqueous medium by using
19
copper-promoted Fe-ZSM-5. Angew Chem Int Ed. 2012;51:5129-5133.
20
21
8. Wan Y, Ma J, Wang Z, Zhou W, Kaliaguine S. Selective catalytic reduction of NO over Cu-Al-MCM-41.
J Catal. 2004;227:242-252.
22
9. Richter M, Fait MJG, Eckelt R, Schreier E, Schneider M, Pohl M-M, Fricke R. Oxidative gas phase
23
carbonylation of methanol to dimethyl carbonate over chloride-free Cu-impregnated zeolite Y catalysts at
24
elevated pressure. Appl Catal B Environ. 2007;73:269-281.
25
10. Richter M, Fait MJG, Eckelt R, Schneider M, Radnik J, Heidemann D, Fricke R. Gas-phase
26
carbonylation of methanol to dimethyl carbonate on chloride-free Cu-precipitated zeolite Y at normal
27
pressure. J Catal. 2007;245:11-24.
28
29
11. Kefirov R, Penkova A, Hadjiivanov K, Dzwigaj S, Che M. Stabilization of Cu+ Ions in BEA Zeolite:
Study by FTIR Spectroscopy of Adsorbed CO and TPR. Micropor Mesopor Mater. 2008;116:180-187.
30
12. Sultana A, Nanba T, Sasaki M, Haneda M, Suzuki K, Hamada H. Selective catalytic reduction of NOx
31
with NH3 over different copper exchanged zeolites in the presence of decane. Catal Today.
32
2011;164:495-499.
33
34
35