Rational Design of a Bi-functional Catalyst for the. Oxydehydration of Glycerol: A Combined. Theoretical and Experimental Study

Transcription

1 Supporting Information Rational Design of a Bi-functional Catalyst for the Oxydehydration of Glycerol: A Combined Theoretical and Experimental Study Yang Sik Yun, Kyung Rok Lee, Hongseok Park, Tae Yong Kim, Danim Yun, Jeong Woo Han, and Jongheop Yi*, World Class University Program of Chemical Convergence for Energy & Environment, Institute of Chemical Processes School of Chemical and Biological Engineering Seoul National University, Seoul , Republic of Korea Department of Chemical Engineering, University of Seoul, Seoul , Republic of Korea *To whom correspondence should be addressed: jyi@snu.ac.kr Tel: CONTENTS Details for modeling MoVW Fig. S1-6 Table S1-8 References S1

2 Details for modeling MoVW For the development of the MoVW model, we considered possible configurations of MoVW-X (X denotes for the molar ratio of tungsten to vanadium in the preparation solution) models by varying the positions of tungsten atoms. We chose highly possible (thermodynamically stable) configurations for MoVW-1, MoVW-3, MoVW-5, and MoVW-7 models among a large number of configurations for MoVW models. For the reliable selection of possible configurations, we developed the most probable MoV model based on atomic occupancy S1, and calculated substitution energy and probability S2,S3 of a tungsten atom for molybdenum and vanadium atom at various sites in MoV model (Figure S1, Table S1, and Table S2). Then, we determined possible configurations by substituting tungsten atoms at the most stable site and the comparably stable sites, taking compositions of MoVW models into consideration. After the most probable configuration was determined among the possible ones, we substituted tungsten atoms at the next stable sites in the most probable model step by step, up to MoVW-7 model. The substitution probability of tungsten for molybdenum and vanadium in MoV model is in the order of Mo7 > Mo4 > Mo1, Mo2, Mo6 > Mo3 > Mo5, and V1 > V2 > V3, respectively (Table S2). To develop the MoVW-1 model, four molybdenum atoms are needed to be replaced by tungsten atoms from MoV model. So, we considered five types of configurations by combination of the two most possible sites (Mo7 and Mo4) (see Figure S1 and Table S5). The results of energy and probability calculations in Table S5 confirm that the configuration where four tungsten atoms are located at Mo7 site is the most probable, with a value of 72.4 %. In the case of MoVW-3, six tungsten atoms are needed to be substituted for four molybdenum atoms as well as two vanadium atoms in MoVW-1 model. Based on the probability of substitution (Table S2), Mo4 site is the most probable, and Mo1, Mo2, and S2

3 Mo6 sites could be next candidates for substitution sites of tungsten with the same probability. For accuracy in developing the MoVW-3 model, we calculated the substitution energy and the probability of a tungsten atom for remaining molybdenum and vanadium sites in the MoVW-1 model (Table S3). The Mo6 site was preferable to the other sites (Mo1 and Mo2) in the substitution of tungsten. In the case of vanadium sites, the V1 site exhibited a 98.4% substitution probability, which indicates that V2 and V3 site are not necessary to be considered as substitution sites. Therefore, five configurations of MoVW-3 model were considered, and the most stable configuration was confirmed (Table S6). In the same way, substitutional energy and probability of a tungsten atom in MoVW-3 were calculated (Table S4). Then, ten types of possible configurations for MoVW-5 model were considered, and the most stable configuration was confirmed (Table S7). For MoVW-7, five possible configurations were taken into account, and the results are listed in Table S8. S3

4 Figure S1. Incorporation sites of tungsten species in the MoV structure (Top view of MoV structure). The atomic coordinates are taken from previous report. S1 Value in parenthesis indicates total number of each site in unit cell. S4

5 Figure S2. Calculation models (1 1 1) of a) MoV, b) MoVW-1, c) MoVW-3, d) MoVW-5, and e) MoVW-7 catalysts viewed from [001] direction. Rectangles in each model indicate a primitive unit cell. S5

6 Figure S3. Calculated charge density differences for a) MoVW-3 and b) MoVW-7. Green color indicates a loss of electrons while pink shows a gain of electrons. Isosurface: S6

7 Figure S4. UV-vis spectra of diluted a) MoV, b) MoVW-1, c) MoVW-3, d) MoVW-5, e) MoVW-7, and f) MoVW-9 solutions. S7

8 Figure S5. TEM images of the WO 3 catalyst prepared by a hydrothermal method. S8

9 Figure S6. (A) FT-IR and (B) Raman spectra of a) MoV, b) MoVW-1, c) MoVW-3, d) MoVW-5, e) MoVW-7, and f) MoVW-9 catalysts. S9

10 Table S1. DFT-calculated substitutional and interstitial insertion energies of tungsten into various positions in MoV structure. Type Position Insertion energy of W (ev) Substitutional insertion (E S ) Mo Mo Mo Mo Mo Mo Mo V V V Interstitial insertion (E I ) H H S10

11 Table S2. Probability of substitution of tungsten for molybdenum and vanadium at various positions in MoV model. Type of atom Position Probability a (%) Mo Mo1 7.6 Mo2 7.6 Mo3 3.5 Mo Mo5 0.2 Mo6 7.6 Mo V V V V3 0.0 a Probability (P i ) of substitution of tungsten for molybdenum and vanadium at various positions was calculated by following equation S2,S3 : = 1 exp where k = ev K -1 is Boltzmann s constant, E i is the substitutional energy of tungsten for molybdenum and vanadium at various positions in MoV model, T = 448 K is synthesis temperature of MoVW catalyst, and = exp is normalization factor. S11

12 Table S3. Energy and probability of substitution of tungsten for molybdenum and vanadium at various positions in MoVW-1 model. Type of atom Position Substitution energy a (ev) Probability b (%) Mo Mo Mo Mo Mo Mo Mo V V V V a Substitution energy of a tungsten atom in MoVW-1 model was calculated by following equation: E S = (E W sub-movw-1 + E Mo or V ) (E MoVW-1 + E W ) where E W sub-movw-1 is bulk energy of MoVW-1 unit cell in which one tungsten atom is substituted for molybdenum or vanadium atom, E MoVW-1 is bulk energy of most stable MoVW-1 unit cell, E Mo, V, or W is the bulk energy of the corresponding metal per atom. b Probability (P i ) of substitution of tungsten for molybdenum and vanadium at various positions was calculated by following equation S2,S3 : = 1 exp where k = ev K -1 is Boltzmann s constant, E i is the substitutional energy of tungsten for molybdenum and vanadium at various positions in MoVW-1 model, T = 448 K is synthesis temperature of MoVW catalyst, and = exp is normalization factor. S12

13 Table S4. Energy and probability of substitution of tungsten for molybdenum and vanadium at various positions in MoVW-3 model. Type of atom Position Substitution energy a (ev) Probability b (%) Mo Mo Mo Mo Mo Mo V V V a Substitution energy of a tungsten atom in MoVW-3 model was calculated by following equation: E S = (E W sub-movw-3 + E Mo or V ) (E MoVW-3 + E W ) where E W sub-movw-3 is bulk energy of MoVW-3 unit cell in which one tungsten atom is substituted for molybdenum or vanadium atom, E MoVW-3 is bulk energy of most stable MoVW-3 unit cell, E Mo, V, or W is the bulk energy of the corresponding metal per atom. b Probability (P i ) of substitution of tungsten for molybdenum and vanadium at various positions was calculated by following equation S2,S3 : = 1 exp where k = ev K -1 is Boltzmann s constant, E i is the substitutional energy of tungsten for molybdenum and vanadium at various positions in MoVW-3 model, T = 448 K is synthesis temperature of MoVW catalyst, and = exp is normalization factor. S13

14 Table S5. Formation energies and probabilities for various configurations of MoVW-1. Configuration The number of atoms substituted by tungsten atoms Mo7 Mo4 Formation energy a (ev) MoVW-1 (1) MoVW-1 (2) MoVW-1 (3) MoVW-1 (4) MoVW-1 (5) a Formation energy of configuration m (E f,m ) was calculated by following equation: E f,m = (E total,m + ae Mo + be V ) (E MoV + ce W ) Probability of formation for configuration b (%) where E total,m is bulk energy of configuration m for MoVW-1, E MoV is bulk energy of MoV unit cell, E Mo, V, or W is the bulk energy of the corresponding metal per atom, a and b are the number of molybdenum and vanadium atoms substituted by tungsten atoms, and c is the number of tungsten atoms substituted for molybdenum and vanadium atoms. b Probability of formation for configuration m (P m ) was calculated by following equation S2,S3 : = 1 exp, where k = ev K -1 is Boltzmann s constant, E f,m is the formation energy of configuration m, T = 448 K is synthesis temperature of MoVW-1 catalyst, and = exp, is normalization factor. S14

15 Table S6. Formation energies and probabilities for various configurations of MoVW-3 model. Configuration The number of atoms substituted by tungsten atoms Mo4 Mo6 V1 Formation energy a (ev) MoVW-3 (1) MoVW-3 (2) MoVW-3 (3) MoVW-3 (4) MoVW-3 (5) a Formation energy of configuration m (E f,m ) was calculated by following equation: E f,m = (E total,m + ae Mo + be V ) (E MoVW-1 + ce W ) Probability of formation for configuration b (%) where E total,m is bulk energy of configuration m for MoVW-3, E MoVW-1 is bulk energy of most stable MoVW-1 unit cell, E Mo, V, or W is the bulk energy of the corresponding metal per atom, a and b are the number of molybdenum and vanadium atoms substituted by tungsten atoms, and c is the number of tungsten atoms substituted for molybdenum and vanadium atoms. b Probability of formation for configuration m (P m ) was calculated by following equation S2,S3 : = 1 exp, where k = ev K -1 is Boltzmann s constant, E f,m is the formation energy of configuration m, T = 448 K is synthesis temperature of MoVW-3 catalyst, and = exp, is normalization factor. S15

16 Table S7. Formation energies and probabilities for various configurations of MoVW-5 model. Configuration The number of atoms substituted by tungsten atoms Mo1 Mo2 Mo6 V2 Formation energy a (ev) MoVW-5 (1) MoVW-5 (2) MoVW-5 (3) MoVW-5 (4) MoVW-5 (5) MoVW-5 (6) MoVW-5 (7) MoVW-5 (8) MoVW-5 (9) MoVW-5 (10) a Formation energy of configuration m (E f,m ) was calculated by following equation: E f,m = (E total,m + ae Mo + be V ) (E MoVW-3 + ce W ) Probability of formation for configuration b (%) where E total,m is bulk energy of configuration m for MoVW-5, E MoVW-3 is bulk energy of most stable MoVW-3 unit cell, E Mo, V, or W is the bulk energy of the corresponding metal per atom, a and b are the number of molybdenum and vanadium atoms substituted by tungsten atoms, and c is the number of tungsten atoms substituted for molybdenum and vanadium atoms. b Probability of formation for configuration m (P m ) was calculated by following equation S2,S3 : = 1 exp, where k = ev K -1 is Boltzmann s constant, E f,m is the formation energy of configuration m, T = 448 K is synthesis temperature of MoVW-5 catalyst, and = exp, is normalization factor. S16

17 Table S8. Formation energies and probabilities for various configurations of MoVW-7 model. Configuration The number of atoms substituted by tungsten atoms Mo1 Mo2 Mo6 V2 Formation energy a (ev) MoVW-7 (1) MoVW-7 (2) MoVW-7 (3) MoVW-7 (4) MoVW-7 (5) a Formation energy of configuration m (E f,m ) was calculated by following equation: E f,m = (E total,m + ae Mo + be V ) (E MoVW-5 + ce W ) Probability of formation for configuration b (%) where E total,m is bulk energy of configuration m for MoVW-7, E MoVW-5 is bulk energy of most stable MoVW-5 unit cell, E Mo, V, or W is the bulk energy of the corresponding metal per atom, a and b are the number of molybdenum and vanadium atoms substituted by tungsten atoms, and c is the number of tungsten atoms substituted for molybdenum and vanadium atoms. b Probability of formation for configuration m (P m ) was calculated by following equation S2,S3 : = 1 exp, where k = ev K -1 is Boltzmann s constant, E f,m is the formation energy of configuration m, T = 448 K is synthesis temperature of MoVW-7 catalyst, and = exp, is normalization factor. S17

18 References (S1) Desanto Jr., P.; Buttrey, D.J.; Grasselli, R.K.; Lugmair, C.G.; Volpe, A.F.; Toby, B.H.; Vogt, T. Top. Catal. 2003, 23, (S2) Fu, G.; Xu, X.; Sautet, P. Angew. Chem. 2012, 51, (S3) Grau-Crespo, R.; Hamad, S.; Catlow, C.R.A.; de Leeuw, N.H. J. Phys.: Condens. Matter 2007, 19, S18