| 摘要: | 隨著碳中和與永續發展目標的推動，二氧化碳再利用成為近年研究關注的重點方向。其中，環氧化物與二氧化碳進行環加成反應生成環狀碳酸酯，不僅具原子經濟性，其產物亦可應用於溶劑、電解液與高分子材料單體等領域。然而，由於此反應熱力學穩定性高，需藉助有效催化劑以提升轉化效率與選擇性。
本研究以鐵金屬有機骨架材料（Metal–Organic Frameworks, MOFs）為基礎，採用後修飾法（post-modification）改質 NH2-MIL-53(Fe)、NH2-MIL-235(Fe) 與 NH2-MIL-101(Fe)，並將其應用於催化 二氧化碳與環氧丁烷的開環反應。經由 XRD、FT-IR、TGA、TEM 及 EDS 等分析技術確認材料在結構與官能基上的變化。催化反應則分別於常溫與 55 °C 下進行，以評估其催化效率與產物選擇性。
實驗結果顯示，後修飾顯著影響 MOF 的孔洞結構與官能基，進而提升其催化活性與產物選擇性。其中，修飾五天之 MIL-53 具有適量的碘負載量(13.8 wt%)及最多的二氧化碳吸收量(10.7 cc/g)，於 55°C 下展現最好的反應速率與選擇性，為本研究中表現最佳的觸媒。MIL-53 的催化表現則受修飾天數影響，顯示結構穩定性與修飾程度對催化性能具有高度相關性；MIL235則隨修飾時間增加其催化速率和選擇率亦增加。本研究驗證後修飾法應用於 MOF 催化劑設計之可行性，並提供 MIL 系列Fe-MOF 結構與催化性之對應資料，對於未來發展高效二氧化碳轉化觸媒具參考價值。
;With the increasing attention on carbon neutrality and sustainable development, carbon dioxide (CO₂) utilization has become a key focus in recent research. Among various pathways, the cycloaddition reaction between epoxides and CO₂ to produce cyclic carbonates has attracted attention due to its atom economy and the versatile applications of the products in solvents, electrolytes, and polymer precursors. However, due to the high thermodynamic stability of CO₂, efficient catalysts are required to improve the conversion rate and product selectivity.
In this study, iron-based metal–organic frameworks (Fe-MOFs), including NH₂-MIL-53(Fe), NH₂-MIL-235(Fe), and NH₂-MIL-101(Fe), were modified via a post-modification strategy and subsequently used as catalysts for the cycloaddition reaction between carbon dioxide and 1,2-epoxybutane. The structure of the catalysts and its chemical compositions were characterized by XRD, FT-IR, TGA, TEM, and EDS analyses. Catalytic performance was evaluated under both ambient temperature and 55 °C to gain their activity and selectivity.
The results showed that post-modification significantly altered the pore structures and functionalities of the MOFs, leading to enhanced catalytic activity and product selectivity. Among the catalysts, MIL-53 modified for five days exhibited an appropriate iodide loading (13.8 wt%) and the highest CO₂ uptake (10.7 cc/g), showing the best reaction rate and selectivity at 55 °C, and was identified as the most effective catalyst in this study. The catalytic performance of MIL-53 was strongly influenced by the modification time, indicating a relationship between structural stability, modification degree, and catalytic behavior. For MIL-235, both conversion rate and selectivity increased with longer modification durations. Overall, this work demonstrates the feasibility of post-modification strategies in MOF catalyst design and provides structure–performance data for Fe-based MIL series MOFs, offering valuable insights for the future development of efficient CO₂ conversion catalysts. |
