金屬有機骨架(Metal Organic Framework, MOF) 是一種常見的功能性孔洞材料，因其製備方法簡單、官能基可設計性、可調節的孔徑且具有高比表面積等優點使其成為研究中常見的材料。由於其微孔尺寸窄且具有路易斯鹼性位點可以作為二氧化碳捕捉的優良固體吸附劑。
本研究以簡單的矽烷偶合反應使親水性MOF具有疏水性，成功解決濕度敏感MOF的水穩定性問題。疏水修飾後MOF的水接觸角顯著提高，A520(Al) C1-S 128∘、MOF-303(Al) C1-S 136∘、MIL-101-NH2(Al) C1-S 133∘、MOF-74(Mg) C1-S 98∘。經過疏水修飾後的MOF仍然保持著二氧化碳吸能力，A520(Al) C1-S 2.4 mmol/g、MOF-303(Al) C1-S 4.4 mmol/g， MOF-74(Mg) C1-S 4.5 mmol/g、MIL-101-NH2(Al) C1-S 3.4 mmol/g。研究結果顯示，具有Al-OH結構的MOF是製備矽烷疏水修飾MOF的關鍵條件，透過形成Si-O-Al鍵結，在MOF表面建立疏水塗層，降低與二氧化碳競爭吸附的水氣吸附量。

Metal-organic frameworks (MOFs) are widely studied functional porous materials due to their simplicity of synthesis, designable functional groups, tunable pore sizes, and high surface areas. They are particularly attractive for their potential application as solid adsorbents for carbon dioxide (CO2) capture. However, MOFs can be sensitive to moisture, which influences their stability and performance.
In this study, a simple and effective approach was employed to address the moisture sensitivity of MOFs. By utilizing a silane coupling reaction, hydrophilic MOFs were transformed into hydrophobic materials. After hydrophobic modification increased the water contact angles of the MOFs, as demonstrated by the observed values of A520(Al) C1-S at 128°, MOF-303(Al) C1-S at 136°, MIL-101-NH2(Al) C1-S at 133°, and MOF-74(Mg) C1-S at 98°.
Importantly, the hydrophobic modification did not compromise the CO2 adsorption capacity of the MOFs. The modified MOFs retained their ability to capture CO2, with adsorption capacities of A520(Al) C1-S at 2.4 mmol/g, MOF-303(Al) C1-S at 4.4 mmol/g, MOF-74(Mg) C1-S at 4.5 mmol/g, and MIL-101-NH2(Al) C1-S at 3.4 mmol/g.
The results revealed that the presence of an Al-OH structure in the MOFs played a crucial role in the successful hydrophobic modification. Through the formation of Si-O-Al bonds, a hydrophobic coating was created on the surface of the MOFs, which effectively reduced the moisture adsorption competing with CO2 adsorption.
Overall, this study demonstrates the successful transformation of hydrophilic MOFs into hydrophobic materials through a simple silane coupling reaction. The hydrophobic modification improved the water stability of the MOFs while preserving their CO2 adsorption capacity, thereby expanding their potential applications in CO2 capture and separation processes.

1. Huang, H.; Wang, L.; Zhang, X.; Zhao, H.; Gu, Y. CO2-Selective Capture from Light Hydrocarbon Mixtures by Metal-Organic Frameworks: A Review Clean Technologies [Online], 2023, p. 1-24.
2. Férey, G., Hybrid porous solids: past, present, future. Chemical Society Reviews 2008, 37 (1), 191-214.
3. Lu, W.; Wei, Z.; Gu, Z.-Y.; Liu, T.-F.; Park, J.; Park, J.; Tian, J.; Zhang, M.; Zhang, Q.; Gentle Iii, T.; Bosch, M.; Zhou, H.-C., Tuning the structure and function of metal–organic frameworks via linker design. Chemical Society Reviews 2014, 43 (16), 5561-5593.
4. Wang, S.; Wang, Q.; Feng, X.; Wang, B.; Yang, L., Explosives in the Cage: Metal–Organic Frameworks for High-Energy Materials Sensing and Desensitization. Advanced Materials 2017, 29 (36), 1701898.
5. Danewalia, S. S.; Singh, K., Bioactive glasses and glass–ceramics for hyperthermia treatment of cancer: state-of-art, challenges, and future perspectives. Materials Today Bio 2021, 10, 100100.
6. Li, H.; Eddaoudi, M.; O'Keeffe, M.; Yaghi, O. M., Design and synthesis of an exceptionally stable and highly porous metal-organic framework. Nature 1999, 402 (6759), 276-279.
7. Slater, A. G.; Cooper, A. I., Function-led design of new porous materials. Science 2015, 348 (6238), aaa8075.
8. Coelho, J. A.; Ribeiro, A. M.; Ferreira, A. F. P.; Lucena, S. M. P.; Rodrigues, A. E.; Azevedo, D. C. S. d., Stability of an Al-Fumarate MOF and Its Potential for CO2 Capture from Wet Stream. Industrial & Engineering Chemistry Research 2016, 55 (7), 2134-2143.
9. Lee, J.; Farha, O. K.; Roberts, J.; Scheidt, K. A.; Nguyen, S. T.; Hupp, J. T., Metal–organic framework materials as catalysts. Chemical Society Reviews 2009, 38 (5), 1450-1459.
10. Li, Z.; Shi, K.; Zhai, L.; Wang, Z.; Wang, H.; Zhao, Y.; Wang, J., Constructing multiple sites of metal-organic frameworks for efficient adsorption and selective separation of CO2. Separation and Purification Technology 2023, 307, 122725.
11. Wang, Y.; LeVan, M. D., Adsorption Equilibrium of Carbon Dioxide and Water Vapor on Zeolites 5A and 13X and Silica Gel: Pure Components. Journal of Chemical & Engineering Data 2009, 54 (10), 2839-2844.
12. Seoane, B.; Téllez, C.; Coronas, J.; Staudt, C., NH2-MIL-53(Al) and NH2-MIL-101(Al) in sulfur-containing copolyimide mixed matrix membranes for gas separation. Separation and Purification Technology 2013, 111, 72-81.
13. Takashima, Y.; Martínez, V. M.; Furukawa, S.; Kondo, M.; Shimomura, S.; Uehara, H.; Nakahama, M.; Sugimoto, K.; Kitagawa, S., Molecular decoding using luminescence from an entangled porous framework. Nature Communications 2011, 2 (1), 168.
14. Corma, A.; García, H.; Llabrés i Xamena, F. X., Engineering Metal Organic Frameworks for Heterogeneous Catalysis. Chemical Reviews 2010, 110 (8), 4606-4655.
15. ElMekawy, A.; Hegab, H. M.; Mohanakrishna, G.; Elbaz, A. F.; Bulut, M.; Pant, D., Technological advances in CO2 conversion electro-biorefinery: A step toward commercialization. Bioresource Technology 2016, 215, 357-370.
16. Kondaveeti, S.; Abu-Reesh, I. M.; Mohanakrishna, G.; Bulut, M.; Pant, D., Advanced Routes of Biological and Bio-electrocatalytic Carbon Dioxide (CO2) Mitigation Toward Carbon Neutrality. Frontiers in Energy Research 2020, 8.
17. Siriwardane, R. V.; Shen, M.-S.; Fisher, E. P.; Poston, J. A., Adsorption of CO2 on Molecular Sieves and Activated Carbon. Energy & Fuels 2001, 15 (2), 279-284.
18. Kim, H. R.; Yoon, T.-U.; Kim, S.-I.; An, J.; Bae, Y.-S.; Lee, C. Y., Beyond pristine MOFs: carbon dioxide capture by metal–organic frameworks (MOFs)-derived porous carbon materials. RSC Advances 2017, 7 (3), 1266-1270.
19. McDonald, T. M.; Mason, J. A.; Kong, X.; Bloch, E. D.; Gygi, D.; Dani, A.; Crocellà, V.; Giordanino, F.; Odoh, S. O.; Drisdell, W. S.; Vlaisavljevich, B.; Dzubak, A. L.; Poloni, R.; Schnell, S. K.; Planas, N.; Lee, K.; Pascal, T.; Wan, L. F.; Prendergast, D.; Neaton, J. B.; Smit, B.; Kortright, J. B.; Gagliardi, L.; Bordiga, S.; Reimer, J. A.; Long, J. R., Cooperative insertion of CO2 in diamine-appended metal-organic frameworks. Nature 2015, 519 (7543), 303-308.
20. Alezi, D.; Belmabkhout, Y.; Suyetin, M.; Bhatt, P. M.; Weseliński, Ł. J.; Solovyeva, V.; Adil, K.; Spanopoulos, I.; Trikalitis, P. N.; Emwas, A.-H.; Eddaoudi, M., MOF Crystal Chemistry Paving the Way to Gas Storage Needs: Aluminum-Based soc-MOF for CH4, O2, and CO2 Storage. Journal of the American Chemical Society 2015, 137 (41), 13308-13318.
21. Asif, M.; Suleman, M.; Haq, I.; Jamal, S. A., Post-combustion CO2 capture with chemical absorption and hybrid system: current status and challenges. Greenhouse Gases: Science and Technology 2018, 8 (6), 998-1031.
22. Wu, H.; Simmons, J. M.; Srinivas, G.; Zhou, W.; Yildirim, T., Adsorption Sites and Binding Nature of CO2 in Prototypical Metal−Organic Frameworks: A Combined Neutron Diffraction and First-Principles Study. The Journal of Physical Chemistry Letters 2010, 1 (13), 1946-1951.
23. Gaab, M.; Trukhan, N.; Maurer, S.; Gummaraju, R.; Müller, U., The progression of Al-based metal-organic frameworks – From academic research to industrial production and applications. Microporous and Mesoporous Materials 2012, 157, 131-136.
24. Duan, J.; Jin, W.; Kitagawa, S., Water-resistant porous coordination polymers for gas separation. Coordination Chemistry Reviews 2017, 332, 48-74.
25. Ahmadipouya, S.; Ahmadijokani, F.; Molavi, H.; Rezakazemi, M.; Arjmand, M., CO2/CH4 separation by mixed-matrix membranes holding functionalized NH2-MIL-101(Al) nanoparticles: Effect of amino-silane functionalization. Chemical Engineering Research and Design 2021, 176, 49-59.
26. Tang, P.-H.; So, P. B.; Li, W.-H.; Hui, Z.-Y.; Hu, C.-C.; Lin, C.-H., Carbon Dioxide Enrichment PEBAX/MOF Composite Membrane for CO2 Separation. Membranes 2021, 11 (6), 404.
27. Bao, Z.; Yu, L.; Ren, Q.; Lu, X.; Deng, S., Adsorption of CO2 and CH4 on a magnesium-based metal organic framework. Journal of Colloid and Interface Science 2011, 353 (2), 549-556.
28. Liu, S.; Sun, D.; Tian, H., Novel hydrophobic catalysts to promote hydration at the water–oil interface. RSC Advances 2021, 11 (30), 18299-18307.
29. Choi, S.; Drese, J. H.; Jones, C. W., Adsorbent Materials for Carbon Dioxide Capture from Large Anthropogenic Point Sources. ChemSusChem 2009, 2 (9), 796-854.
30. Schueremans, L.; Van Gemert, D.; Giessler, S., Chloride penetration in RC-structures in marine environment – Long term assessment of a preventive hydrophobic treatment. Construction and Building Materials 2007, 21 (6), 1238-1249.
31. Cai, Y.; Li, J.; Yi, L.; Yan, X.; Li, J., Fabricating superhydrophobic and oleophobic surface with silica nanoparticles modified by silanes and environment-friendly fluorinated chemicals. Applied Surface Science 2018, 450, 102-111.
32. Kim, K.-S.; Kim, J.-H.; Lee, H.-J.; Lee, S.-R., Tribology issues in nanoimprint lithography. Journal of Mechanical Science and Technology 2010, 24 (1), 5-12.
33. Arkles, B., Tailoring Surfaces with Silanes. 1977, 7, 766-778.
34. Kulkarni, S. A.; Ogale, S. B.; Vijayamohanan, K. P., Tuning the hydrophobic properties of silica particles by surface silanization using mixed self-assembled monolayers. Journal of Colloid and Interface Science 2008, 318 (2), 372-379.
35. Lin, H.; Hu, Q.; Liao, T.; Zhang, X.; Yang, W.; Cai, S. Highly Hydrophobic Cotton Fabrics Modified by Poly(methylhydrogen)siloxane and Fluorinated Olefin: Characterization and Applications Polymers [Online], 2020.
36. Maciejewski, H.; Karasiewicz, J.; Dutkiewicz, M.; Marciniec, B., Hydrophobic Materials Based on Fluorocarbofunctional Spherosilicates. Silicon 2015, 7 (2), 201-209.
37. Nurhan Onar, C.; Buket, A., Sol-Gel Applications in Textile Finishing Processes. In Recent Applications in Sol-Gel Synthesis, Usha, C., Ed. IntechOpen: Rijeka, 2017; p Ch. 13.
38. Lu, Y.; Sathasivam, S.; Song, J.; Crick, C. R.; Carmalt, C. J.; Parkin, I. P., Robust self-cleaning surfaces that function when exposed to either air or oil. Science 2015, 347 (6226), 1132-1135.
39. Shayesteh, H.; Norouzbeigi, R.; Rahbar-Kelishami, A., Evaluation of superhydrophobicity of chemical-resistant magnetic spiky nickel nanowires grafted with silane coupling agent for highly efficient oil/water separation. Surfaces and Interfaces 2022, 28, 101685.
40. Lin, J.-B.; Nguyen, T. T. T.; Vaidhyanathan, R.; Burner, J.; Taylor, J. M.; Durekova, H.; Akhtar, F.; Mah, R. K.; Ghaffari-Nik, O.; Marx, S.; Fylstra, N.; Iremonger, S. S.; Dawson, K. W.; Sarkar, P.; Hovington, P.; Rajendran, A.; Woo, T. K.; Shimizu, G. K. H., A scalable metal-organic framework as a durable physisorbent for carbon dioxide capture. Science 2021, 374 (6574), 1464-1469.
41. Lyu, H.; Chen, O. I.-F.; Hanikel, N.; Hossain, M. I.; Flaig, R. W.; Pei, X.; Amin, A.; Doherty, M. D.; Impastato, R. K.; Glover, T. G.; Moore, D. R.; Yaghi, O. M., Carbon Dioxide Capture Chemistry of Amino Acid Functionalized Metal–Organic Frameworks in Humid Flue Gas. Journal of the American Chemical Society 2022, 144 (5), 2387-2396.
42. Zhang, W.; Hu, Y.; Ge, J.; Jiang, H.-L.; Yu, S.-H., A Facile and General Coating Approach to Moisture/Water-Resistant Metal–Organic Frameworks with Intact Porosity. Journal of the American Chemical Society 2014, 136 (49), 16978-16981.
43. Cadiau, A.; Belmabkhout, Y.; Adil, K.; Bhatt, P. M.; Pillai, R. S.; Shkurenko, A.; Martineau-Corcos, C.; Maurin, G.; Eddaoudi, M., Hydrolytically stable fluorinated metal-organic frameworks for energy-efficient dehydration. Science 2017, 356 (6339), 731-735.
44. Cohen, S. M., The Postsynthetic Renaissance in Porous Solids. Journal of the American Chemical Society 2017, 139 (8), 2855-2863.
45. Sharma, R.; Sürmeli, D.; Van Assche, T. R. C.; Tiriana, S.; Delplancke, M.-P.; Baron, G. V.; Denayer, J. F. M., An ultra-permeable hybrid Mg-MOF-74-Melamine sponge composite for fast dynamic gas separation. Microporous and Mesoporous Materials 2022, 343, 112146.
46. Wang, L.; Zhang, F.; Wang, C.; Li, Y.; Yang, J.; Li, L.; Li, J., Ethylenediamine-functionalized metal organic frameworks MIL-100(Cr) for efficient CO2/N2O separation. Separation and Purification Technology 2020, 235, 116219.
47. Vrtovec, N.; Mazaj, M.; Buscarino, G.; Terracina, A.; Agnello, S.; Arčon, I.; Kovač, J.; Zabukovec Logar, N., Structural and CO2 Capture Properties of Ethylenediamine-Modified HKUST-1 Metal–Organic Framework. Crystal Growth & Design 2020, 20 (8), 5455-5465.
48. Han, Z.; Li, J.; Lu, W.; Wang, K.; Chen, Y.; Zhang, X.; Lin, L.; Han, X.; Teat, S. J.; Frogley, M. D.; Yang, S.; Shi, W.; Cheng, P., A {Ni12}-Wheel-Based Metal–Organic Framework for Coordinative Binding of Sulphur Dioxide and Nitrogen Dioxide. Angewandte Chemie International Edition 2022, 61 (6), e202115585.
49. Kim, S.-N.; Kim, J.; Kim, H.-Y.; Cho, H.-Y.; Ahn, W.-S., Adsorption/catalytic properties of MIL-125 and NH2-MIL-125. Catalysis Today 2013, 204, 85-93.
50. Kim, J.; Kim, W. Y.; Ahn, W.-S., Amine-functionalized MIL-53(Al) for CO2/N2 separation: Effect of textural properties. Fuel 2012, 102, 574-579.
51. Zhou, Z.; Mei, L.; Ma, C.; Xu, F.; Xiao, J.; Xia, Q.; Li, Z., A novel bimetallic MIL-101(Cr, Mg) with high CO2 adsorption capacity and CO2/N2 selectivity. Chemical Engineering Science 2016, 147, 109-117.
52. Babar, M.; Mubashir, M.; Mukhtar, A.; Saqib, S.; Ullah, S.; Bustam, M. A.; Show, P. L., Sustainable functionalized metal-organic framework NH2-MIL-101(Al) for CO2 separation under cryogenic conditions. Environmental Pollution 2021, 279, 116924.
53. Jajko, G.; Kozyra, P.; Gutiérrez-Sevillano, J. J.; Makowski, W.; Calero, S., Carbon Dioxide Capture Enhanced by Pre-Adsorption of Water and Methanol in UiO-66. Chemistry – A European Journal 2021, 27 (59), 14653-14659.
54. Saha, D.; Bao, Z.; Jia, F.; Deng, S., Adsorption of CO2, CH4, N2O, and N2 on MOF-5, MOF-177, and Zeolite 5A. Environmental Science & Technology 2010, 44 (5), 1820-1826.
55. Alvarez, E.; Guillou, N.; Martineau, C.; Bueken, B.; Van de Voorde, B.; Le Guillouzer, C.; Fabry, P.; Nouar, F.; Taulelle, F.; de Vos, D.; Chang, J.-S.; Cho, K. H.; Ramsahye, N.; Devic, T.; Daturi, M.; Maurin, G.; Serre, C., The Structure of the Aluminum Fumarate Metal–Organic Framework A520. Angewandte Chemie International Edition 2015, 54 (12), 3664-3668.
56. Hanikel, N.; Prévot, M. S.; Fathieh, F.; Kapustin, E. A.; Lyu, H.; Wang, H.; Diercks, N. J.; Glover, T. G.; Yaghi, O. M., Rapid Cycling and Exceptional Yield in a Metal-Organic Framework Water Harvester. ACS Central Science 2019, 5 (10), 1699-1706.
57. Fathieh, F.; Kalmutzki, M. J.; Kapustin, E. A.; Waller, P. J.; Yang, J.; Yaghi, O. M., Practical water production from desert air. Science Advances 2018, 4 (6), eaat3198.
58. Bromberg, L.; Su, X.; Hatton, T. A., Heteropolyacid-Functionalized Aluminum 2-Aminoterephthalate Metal-Organic Frameworks As Reactive Aldehyde Sorbents and Catalysts. ACS Applied Materials & Interfaces 2013, 5 (12), 5468-5477.
59. Srirambalaji, R.; Hong, S.; Natarajan, R.; Yoon, M.; Hota, R.; Kim, Y.; Ho Ko, Y.; Kim, K., Tandem catalysis with a bifunctional site-isolated Lewis acid–Brønsted base metal–organic framework, NH2-MIL-101(Al). Chemical Communications 2012, 48 (95), 11650-11652.
60. Xu, Q.; Fang, L.; Fu, Y.; Xiao, Q.; Zhang, F.; Zhu, W., Synthesis, characterization, and CO2 adsorption properties of metal–organic framework NH2–MIL–101(V). Materials Letters 2020, 264, 127402.
61. Dietzel, P. D. C.; Johnsen, R. E.; Fjellvåg, H.; Bordiga, S.; Groppo, E.; Chavan, S.; Blom, R., Adsorption properties and structure of CO2 adsorbed on open coordination sites of metal–organic framework Ni2(dhtp) from gas adsorption, IR spectroscopy and X-ray diffraction. Chemical Communications 2008, (41), 5125-5127.
62. Yang, D.-A.; Cho, H.-Y.; Kim, J.; Yang, S.-T.; Ahn, W.-S., CO2 capture and conversion using Mg-MOF-74 prepared by a sonochemical method. Energy & Environmental Science 2012, 5 (4), 6465-6473.