Title Page
Contents
Abstract 9
1. Introduction 10
2. computational chemistry 12
3. Computational details 15
4. Results and Discussion 17
4.1. Reaction Mechanisms for Xylose Decomposition. 17
4.2. Design of Bimetallic Catalysts from Optimized Ni₃/MgO to Ni₂M/MgO (M=3d,4d,5d Transition Metal, TM) 23
4.3. Analysis of catalytic activity 47
4.4. alloy effect 53
5. Conclusions 57
6. References 59
Table 1. Ni₂M clusters adsorption energy on MgO(100) support (M=3d,4d,5d transition metals). 25
Table 2. reaction energy for Ni₂M/MgO catalysts formation. (Ni₃/MgO + M₁ → Ni₂M/MgO + Ni₁) 26
Table 3. Reaction energy and barrier for xylose decomposition of Ni₂M/MgO catalysts. (enthalpy) 44
Table 4. Entropy and zero-point energy(ZPE) data of intermediates. 45
Table 5. Reaction energy and barrier for xylose decomposition of Ni₂M/MgO catalysts. (Gibbs free energy) 46
Table 6. Alloy effect(strain/ligand) contribution of Ni₂M/MgO catalysts (△Estrain=Eads of Ni₃strain /MgO-E ads of Ni₃/MgO, △Eligand=Eads of Ni₂M/MgO-E ads of Ni₃strain /MgO, △E total=△E strain + △E ligand).[이미지참조] 54
Table 7. Bond length of Ni₃strain /MgO when the Ni₂M/MgO convert to Ni₃/MgO. 56
Figure 1. computational methods according to scale. 13
Figure 2. the basic theory of DFT. 14
Figure 3. the reaction mechanism from xylose to ethylene glycol and glycerol precursors. 19
Figure 4. Possible geometries of Ni₃/MgO structure (side and top) (a) linear structure (b) 2D triangle (c) 3D triangle (d) 3D inverted triangle 20
Figure 5. Potential Energy Diagram for xylose decomposition on Ni₃/MgO. Xc, Xc*, Xro*, and (C2+C3)* denote cyclic xylose, adsorbed cyclic xylose, ring-opened xylose, and ethylene...[이미지참조] 21
Figure 6. the most stable adsorption configurations of xylose(C5H10O5) and the transition states on Ni₃/MgO(side and top) (a) xylose (b) first transition state(fig.2) (c) ring-opened xylose (d)...[이미지참조] 22
Figure 7. Possible geometries of Ni₂M/MgO structure(M=3d, 4d, 5d metals). (a), (b), (c) represent 2D structures and (d), (e), (f) 3D structures. 24
Figure 8. Potential Energy Diagram for xylose decomposition on Ni₂M/MgO(M=3d metals). Xc*, Xro*, and (C2+C3)* denotes adsorbed cyclic xylose, ring-opened xylose, and ethylene... 30
Figure 9. the most stable adsorption configurations of xylose(C5H10O5) and the transition states on Ni₂M/MgO(M=Co, Fe, Sc) (a) xylose (b) first transition state (c) ring-opened xylose (d)...[이미지참조] 31
Figure 10. the most stable adsorption configurations of xylose(C5H10O5) and the transition states on Ni₂M/MgO(M=Ti, V) (a) xylose (b) first transition state (c) ring-opened xylose (d)...[이미지참조] 32
Figure 11. Potential Energy Diagram for xylose decomposition on Ni₂M/MgO(M=4d metals). Xc*, Xro*, and (C2+C3)* denotes adsorbed cyclic xylose, ring-opened xylose, and ethylene... 33
Figure 12. the most stable adsorption configurations of xylose(C5H10O5) and the transition states on Ni₂M/MgO(M=Nb, Ru, Tc) (a) xylose (b) first transition state (c) ring-opened xylose...[이미지참조] 34
Figure 13. the most stable adsorption configurations of xylose(C5H10O5) and the transition states on Ni₂M/MgO(M=Y, Zr) (a) xylose (b) first transition state (c) ring-opened xylose (d)...[이미지참조] 35
Figure 14. Potential Energy Diagram for xylose decomposition on Ni₂M/MgO(M=5d metals). Xc*, Xro*, and (C2+C3)* denotes adsorbed cyclic xylose, ring-opened xylose, and ethylene... 36
Figure 15. the most stable adsorption configurations of xylose(C5H10O5) and the transition states on Ni₂M/MgO(M=Au, Hf, Ir) (a) xylose (b) first transition state (c) ring-opened xylose...[이미지참조] 37
Figure 16. the most stable adsorption configurations of xylose(C5H10O5) and the transition states on Ni₂M/MgO(M=Os, Pt, Re) (a) xylose (b) first transition state (c) ring-opened xylose...[이미지참조] 38
Figure 16. the most stable adsorption configurations of xylose(C5H10O5) and the transition states on Ni₂M/MgO(M=W) (a) xylose (b) first transition state (c) ring-opened xylose (d)...[이미지참조] 39
Figure 18. Potential Energy Diagram for xylose decomposition on Ni₂M/MgO(M=3d, 4d, 5d metals). Xc*, Xro*, and (C2+C3)* denotes adsorbed cyclic xylose, ring-opened xylose, and... 40
Figure 19. volcano plot for the decomposition of xylose on Ni₂M/MgO(M=3d,4d,5d metals). △E RDS, E Xr * denotes activation energy of rate-determining step, the adsorption energy of ring-... 42
Figure 20. the most stable adsorption configurations of xylose(C5H10O5) and the transition states on Ni₂ Rh/MgO, Ni₂ Ta/MgO (a) xylose (b) first transition state (c) ring-opened xylose...[이미지참조] 43
Figure 21. Correlation between adsorption energy of ring-opened xylose and d-band center of M-Ni(M=3d, 4d, 5d metals). 49
Figure 22. The density of states(DOS) of Ni₂Rh/MgO and Ni₂Ta/MgO (a) Ni₂Rh/MgO (b) Ni₂Ta/MgO 50
Figure 23. Correlation between adsorption energy of ring opened xylose and charge polarization of substituted metal(M=3d, 4d, 5d metals) and Ni. 51
Figure 24. Correlation between adsorption energy of ring opened xylose and DOS near Fermi level(-0.25~0 eV) of substituted metal(M=3d, 4d, 5d metals) and Ni. 52