Title Page
Abstract
Contents
1. Introduction 12
1.1. Photocatalytic hydrogen generation 12
1.2. Charge carriers separation via heterostructures formation 15
1.3. Density functional theory in photocatalysis 22
2. Gold-Substituted Silver Nanoclusters for photocatalytic hydrogen generation 27
2.1. Motivation 27
2.2. Previous experimental data 29
2.3. Computation details 33
2.4. Results and discussion 35
2.4.1. HER Overpotential 35
2.4.2. Band edge position 37
2.4.3. Electronic structure NAO(Natural Atomic Orbital) analysis 40
2.4.4. Decomposition stability 45
2.4.5. Conclusions 48
3. Conclusions & outlook 49
3.1. Limitation 49
3.2. Outlook 51
References 52
국문초록 57
Figure 1.1. Diagram illustrating band edge positions for photocatalysts in unfavorable scenarios. A) is unable to undergo the HER (Hydrogen Evolu-... 16
Figure 1.2. Diagram illustrating band edge positions for single & two-photocatalysts systems 18
Figure 1.3. Photocatalytic mechanism involving Type-II heterojunction and Z-scheme systems using photocatalysts (PC1 & PC2). Illustration of (Left)... 20
Figure 2.1. UV-visible spectrum data for nanoclusters(Au₁₂Ag₃₂&Ag₄₄). 30
Figure 2.2. H₂ production & catalytic activity enhancement for photocatalysts(TiO₂, Ag₄₄ /TiO₂, Au₁₂Ag₃₂/TiO₂). 30
Figure 2.3. Absorbance change over time for nanoclusters(Au₁₂Ag₃₂&Ag₄₄). (Reproduced with Permission. 32
Figure 2.4. (Up)the H adsorbate(Red) on nanoclusters (Left)Ag₄₄ & (Right)Au₁₂Ag₃₂, and (Down)Gibbs free energy diagram indicating HER... 36
Figure 2.5. Determined band edge positions (relative to NHE) for Ag₄₄, Au₁₂Ag₃₂, and TiO₂ (Anatase). The green and blue lines represent the... 39
Figure 2.6. Determined molecular orbital (MO) energy levels with their expansion coefficients (weight factors) of (Up)Ag₄₄ and (Down)Au₁₂Ag₃₂. The... 41
Figure 2.7. Computed the proportional weights of atomic orbitals from the core metals within the clusters (e.g., (Up)the core Ag12 of Ag₄₄, and... 43
Figure 2.8. (Up)the H adsorbate(Red) on the selenium site (HSₑ*) of nanoclusters(Left:Ag₄₄, Right:Au₁₂Ag₃₂) and (Down)Calculated Gibbs free...[이미지참조] 46