Spectroscopic and Computational Study of Cr Oxide
Supporting Information Spectroscopic and Computational Study of Cr Oxide Structures and Their Anchoring Sites on ZSM-5 Zeolites Jie Gao1, Yiteng Zheng1, Yadan Tang2, Jih-Mirn Jehng2,3, Robert Grybos4*, Jaroslaw Handzlik5*, Israel E. Wachs2*, Simon G. Podkolzin1*
1Department
of Chemical Engineering and Materials Science, Stevens Institute of Technology, Hoboken, New Jersey 07030 United States
2Operando
Molecular Spectroscopy & Catalysis Laboratory, Department of Chemical and
Biomolecular Engineering, Lehigh University, Bethlehem, Pennsylvania 18015 United States 3Department
of Chemical Engineering, National Chung Hsing University, Taichung, Taiwan, ROC
4Jerzy
Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Kraków, 30-239, Poland
5Faculty
of Chemical Engineering and Technology, Cracow University of Technology, Kraków, 31-155, Poland
*Corresponding Authors: R.G.: [email protected], J.H.: [email protected], I.E.W.: [email protected], S.G.P.: [email protected].
Figures S1-S4 provide an additional 46-T cluster model of the ZSM-5 zeolite structure, reaction rates for 0.8 and 1.6 wt% Cr/ZSM-5 (Si/Al=15) catalysts in catalytic methane dehydroaromatization, and additional optimized structures obtained with Gaussian 09 and VASP DFT calculations.
(a)
(b)
(c)
Figure S1. Additional 46-T cluster model of the ZSM-5 zeolite structure used in Gaussian 09 DFT calculations: (a). Channel, (b). Side and (c). Top views.
(a). C6H6 formation rate
(b). H2 formation rate 0.8 wt% Cr/ZSM-5
1.5
1.5 0.8 wt% Cr/ZSM-5
1.0
0
1.6 wt% Cr/ZSM-5
1.0
1.6 wt% Cr/ZSM-5
0.5
0
2.0
Turnover frequencies (TOF), s-1× 10-2
Turnover frequencies (TOF), s-1× 10-4
2.0
0.5
40 80 120 Time on stream, min
0
0
40 80 120 Time on stream, min
Figure S2. (a). Benzene and (b). Hydrogen formation rates over 0.8 and 1.6 wt% Cr/ZSM-5 (Si/Al=15) catalysts in methane dehydroaromatization with the main reaction 6CH4 = C6H6 + 9H2. Reaction conditions: 100 sccm flow of 10 mol% CH4/Ar, 0.2 g of catalyst, 1023 K.
Page 2 of 3
a. [Cr(=O)2]2+ on 2 [AlO4]- sites
b. (Si-O-)4Cr(=O) in a vacancy defect site
Figure S3. Structures of isolated Cr oxide species anchored on ZSM5 sites obtained with Gaussian 09 DFT calculations using the cluster model in Figure S1: (a). Dioxo [Cr(=O)2]2+ structure anchored on 2 framework [AlO4]- sites in T7-T10 positions and (b). Mono-oxo (SiO-)4Cr(=O) structure in a T7 vacancy defect site with a neighboring framework Al atom in a T10 position.
a. [Cr(=O)2]2+ on 2 [AlO4]- sites
b. [Cr(=O)2]2+ on 2 [AlO4]- sites
c. (Si-O-)4Cr(=O) in a vacancy defect site
Figure S4. Structures of isolated Cr oxide species anchored on ZSM-5 sites obtained with VASP DFT calculations using the full periodic ZSM-5 unit cell. (a). Dioxo [Cr(=O)2]2+ structure anchored on 2 framework [AlO4]- sites in T7-T10 positions. (b). Dioxo [Cr(=O)2]2+ structure anchored on 2 framework [AlO4]- sites in T8-T8 positions. This structure is analogous to the cluster structure in Figure 11a. (c). Mono-oxo (Si-O-)4Cr(=O) structure in a T7 vacancy defect site with a neighboring framework Al atom in a T10 position. This structure is analogous to the cluster structure in Figure S3b.
Page 3 of 3
1Department
of Chemical Engineering and Materials Science, Stevens Institute of Technology, Hoboken, New Jersey 07030 United States
2Operando
Molecular Spectroscopy & Catalysis Laboratory, Department of Chemical and
Biomolecular Engineering, Lehigh University, Bethlehem, Pennsylvania 18015 United States 3Department
of Chemical Engineering, National Chung Hsing University, Taichung, Taiwan, ROC
4Jerzy
Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Kraków, 30-239, Poland
5Faculty
of Chemical Engineering and Technology, Cracow University of Technology, Kraków, 31-155, Poland
*Corresponding Authors: R.G.: [email protected], J.H.: [email protected], I.E.W.: [email protected], S.G.P.: [email protected].
Figures S1-S4 provide an additional 46-T cluster model of the ZSM-5 zeolite structure, reaction rates for 0.8 and 1.6 wt% Cr/ZSM-5 (Si/Al=15) catalysts in catalytic methane dehydroaromatization, and additional optimized structures obtained with Gaussian 09 and VASP DFT calculations.
(a)
(b)
(c)
Figure S1. Additional 46-T cluster model of the ZSM-5 zeolite structure used in Gaussian 09 DFT calculations: (a). Channel, (b). Side and (c). Top views.
(a). C6H6 formation rate
(b). H2 formation rate 0.8 wt% Cr/ZSM-5
1.5
1.5 0.8 wt% Cr/ZSM-5
1.0
0
1.6 wt% Cr/ZSM-5
1.0
1.6 wt% Cr/ZSM-5
0.5
0
2.0
Turnover frequencies (TOF), s-1× 10-2
Turnover frequencies (TOF), s-1× 10-4
2.0
0.5
40 80 120 Time on stream, min
0
0
40 80 120 Time on stream, min
Figure S2. (a). Benzene and (b). Hydrogen formation rates over 0.8 and 1.6 wt% Cr/ZSM-5 (Si/Al=15) catalysts in methane dehydroaromatization with the main reaction 6CH4 = C6H6 + 9H2. Reaction conditions: 100 sccm flow of 10 mol% CH4/Ar, 0.2 g of catalyst, 1023 K.
Page 2 of 3
a. [Cr(=O)2]2+ on 2 [AlO4]- sites
b. (Si-O-)4Cr(=O) in a vacancy defect site
Figure S3. Structures of isolated Cr oxide species anchored on ZSM5 sites obtained with Gaussian 09 DFT calculations using the cluster model in Figure S1: (a). Dioxo [Cr(=O)2]2+ structure anchored on 2 framework [AlO4]- sites in T7-T10 positions and (b). Mono-oxo (SiO-)4Cr(=O) structure in a T7 vacancy defect site with a neighboring framework Al atom in a T10 position.
a. [Cr(=O)2]2+ on 2 [AlO4]- sites
b. [Cr(=O)2]2+ on 2 [AlO4]- sites
c. (Si-O-)4Cr(=O) in a vacancy defect site
Figure S4. Structures of isolated Cr oxide species anchored on ZSM-5 sites obtained with VASP DFT calculations using the full periodic ZSM-5 unit cell. (a). Dioxo [Cr(=O)2]2+ structure anchored on 2 framework [AlO4]- sites in T7-T10 positions. (b). Dioxo [Cr(=O)2]2+ structure anchored on 2 framework [AlO4]- sites in T8-T8 positions. This structure is analogous to the cluster structure in Figure 11a. (c). Mono-oxo (Si-O-)4Cr(=O) structure in a T7 vacancy defect site with a neighboring framework Al atom in a T10 position. This structure is analogous to the cluster structure in Figure S3b.
Page 3 of 3
