| 摘要: | 近幾年金屬有機框架 ( Metal Organic Framework, MOFs ) 是一個備受關注的研究議題，因為此材料在能源存儲與轉換等多個領域具有廣泛的應
用潛力。MOFs 以其高度可設計的結構與多功能性為材料的設計提供了廣泛
的可能性。然而，儘管 MOFs 在理論上具有優秀的性能，其實際應用仍然
面臨結構穩定性和導電性進一步提升的挑戰。為了解決這些問題，摻雜
（Doping）技術逐漸被應用於 MOFs 中，可以有效地調控材料的電子性質，從而提高其導電性、結構穩定性以及吸附能力。因此本研究以密度泛函理論( Density Functional Theory, DFT ) 模擬兩種金屬有機骨架之摻雜行為與水分子吸附影響。第一部分以[Cu2(6-Hmna)(6-mn)]·NH4 為主，探討錫 (Sn) 摻雜對材料結構穩定性與電子特性的影響。模擬結果顯示，在 4% ~ 8%摻雜濃度下具備最低形成能，有良好的熱力學穩定性。水分子主要吸附於 Cu 位點，吸附能由-0.609 eV 下降至 -0.974 eV，並透過電子密度差分析，表明 Sn 的摻雜能有效的提高收吸附能力以及電子轉移效率。第二部分則以 Zn(6-Hmna)2，研究銅 (Cu) 取代對材料的穩定性。結果顯示在 12.5%到 37.5%時具有相對較低的形成能，表明其在此濃度下有最好的穩定性。水分子主要吸附於 Cu 位點，吸附能由 -0.742 eV 下降至 -1.292 eV。結果也顯示在適當的取代下可以改善的 Zn-MOF 的電子結構與水吸附能力。
;In recent years, high conductive metal-organic frameworks have garnered significant research interest due to their broad application potential of MOF in energy storage and generation. MOFs offer a wide range of possibilities for
material design due to their excellent conductivity, high surface and good reaction activities. However, despite their theoretical exceptional performance, practical application of MOFs still faces challenges regarding structural stability and further enhancement of conductivity. To address these issues, doping have gradually been applied to modify the physical properties of MOFs, effectively tuning the material′s electronic properties, thereby improving its conductivity, structural stability, and adsorption capacity.
In this study, we used density functional theory simulations to explore the influences of doping on both the structure and water adsorption performance of two MOFs. In the first part, we focused on [Cu2(6-Hmna)(6-mn)]·NH4 and investigated influence of tin (Sn) doping influences its properties. We observe that doping concentration around 4% to 8% have the lowest formation energy, meaning the structure is thermodynamically stable. Water molecules preferred to
attach onto Cu-sites, and the adsorption energy decrease from -0.609 to -0.974 eV, suggesting better water interaction and enhance charge transfer.
The second part, we focus on Zn(6-Hmna)2, to realize the effect of Cu doping on physical property of Zn(6-Hmna)2 MOFs. The results showed that at doping concentration between 12.5% and 37.5%, the formation energy is relatively low, meaning the structure is thermodynamically stable. Water molecules preferred to bind to Cu sites, and the adsorption energy decrease from -0.609 to -0.974 eV. As
a result, Cu doping improved the electronic structure and water adsorption ability of Zn-based MOF.
Overall, this works highlights how to carefully chose doping concentration can enhance both the stability and functionality of MOFs materials, especially for applications related to water adsorption and energy system. |
