Impact statement
This review article provides a comprehensive overview of the recent advances in metal–organic frameworks (MOFs) for direct air capture (DAC) applications in capturing CO2. It summarizes the general design principles and performances of wide varieties of MOF categories, including hydroxy-rich, open-metal sites and amine-functionalized MOFs. By focusing and highlighting their individual adsorption behavior under ultradiluted CO2 concentrations. This review also outlines the major challenges that are associated within these MOF categories, including costs, long-term material stability toward practical DAC performances. By connecting the use in real-life DAC application requirements and scientific materials design, this review article will be beneficial for engineers and researchers that are interested in this scientific field in seeking developments in the next-generation MOF gas adsorbents for DAC environments toward a more sustainable environment.
Introduction
Carbon dioxide (CO2), the primary source of greenhouse gases, has increased significantly in the atmosphere due to the acceleration of numerous anthropogenic activities, including fossil fuel combustion, deforestation and industrial processes (Salam and Noguchi, Reference Salam and Noguchi2005; Anwar et al., Reference Anwar, Iftikhar, Khush Bakhat, Sohail, Baqar, Yasir, Nizami, Inamuddin and Lichtfouse2019; Shakoor et al., Reference Shakoor, Ashraf, Shakoor, Mustafa, Rehman and Altaf2020; Yoro and Daramola, Reference Yoro, Daramola, Rahimpour, Farsi and Makarem2020). According to the International Energy Agency records, global CO2 emissions from industrial production and energy use have reached a record high in 2024 (Ashraf and Sagheer, Reference Ashraf and Sagheer2025). The level of CO2 emissions has increased to about a total of 37.8 gigatonnes (Gt) in the year of 2024, these data have risen by 0.8% since 2023 (Crippa et al., Reference Crippa, Oreggioni, Guizzardi, Muntean, Schaaf, Lo Vullo, Solazzo, Monforti-Ferrario, Olivier and Vignati2019; Kabir et al., Reference Kabir, Kim and Kwon2023). As the level of greenhouse gases continues to rise, it is predicted that the total greenhouse gas emissions will grow to about a total 53 Gt by the year of 2025 (Nielsen et al., Reference Nielsen, Winther, Mikkelsen, Gyldenkærne, Lyck, Plejdrup, Hoffmann, Thomsen and Fauser2009; Levin and Rich, Reference Levin and Rich2017; Santos et al., Reference Santos, de Carvalho and de Souza Penin2025).
With the fast increase in the CO2 concentrations in the current stages, it will be extremely difficult to limit the global average temperature to well-below 2 °C above preindustrial levels (Schurer et al., Reference Schurer, Mann, Hawkins, Tett and Hegerl2017; Allen et al., Reference Allen, Antwi-Agyei, Aragon-Durand, Babiker, Bertoldi, Bind, Brown, Buckeridge, Camilloni and Cartwright2019). Currently, the development of carbon removal techniques has therefore become crucial toward the reduction of CO2 in the atmosphere. To reach this goal, an emerging negative-emission technology known as direct air capture (DAC) has been introduced to achieve global carbon neutrality and aim to limit global warming below 2°C by 2100 (Akimoto et al., Reference Akimoto, Sano, Oda, Kanaboshi and Nakano2021; Li and Yao, Reference Li and Yao2024).
Despite all the global challenges faced by the rapidly increasing level of CO2, DAC has attracted significant attention as the most promising strategy in reducing CO2 concentrations directly from the atmosphere. This foundation concept was first discovered by Klaus Lackner in the 1990s. He proposed that ‘CO2 can be extracted from the atmosphere at any location, making sequestration independent of the original emission site’ (Lackner et al., Reference Lackner, Ziock and Grimes1999). This concept has offered valuable advantages in DAC over other forms of carbon removal methods in the reduction of past gas emissions and restoring the atmospheric CO2 concentration to an optimal level.
In particular, the characteristic of high flexibility and long-term climate impact provided by DAC can overtake the traditional carbon capture methods. DAC can be performed anywhere and anytime, enabling targeted removal of gas molecules from widely distributed emission sources from centuries ago (Shaffer, Reference Shaffer2010). However, conventional capturing methods like post-combustion and precombustion processes can only capture CO2 gases from concentrated point sources such as industry and power plants (Wang et al., Reference Wang, Zhao, Otto, Robinius and Stolten2017; Madejski et al., Reference Madejski, Chmiel, Subramanian and Kuś2022; Ibigbami et al., Reference Ibigbami, Onilearo and Akinyeye2024).
The current developed in DAC can be categorized into two classes: (1) liquid-based sorbents and (2) solid-based sorbents (Wang et al., Reference Wang, Fu, Wen, Ning, Helal, Salem, Xu, El-Bahy, Huang and Guo2022; Shi et al., Reference Shi, Lee, Liu, Kim, Alahmed, Jamal, Wang and Park2023). Liquid-based sorbents, typically in aqueous solutions, such as strong bases including potassium hydroxide and sodium carbonate, as well as amines and amino acids, have demonstrated great CO2 gas capture capabilities due to their strong chemical reactivity even at low CO2 concentrations, they can bind to CO2 chemically through carbamate or bicarbonate formations (Ochedi et al., Reference Ochedi, Yu, Yu, Liu and Hussain2021; Sun et al., Reference Sun, He and Duan2025). These liquid-based sorbents, typically in aqueous form, can react with CO2 to form potassium carbonate and sodium bicarbonate and carbamates, respectively, which highlights their effectiveness in CO2 chemical reactivity in DAC (Maniarasu et al., Reference Maniarasu, Rathore and Murugan2023; Tang, Reference Tang2025; Van der Spek et al., Reference Van der Spek, Bardow, Baum, Bolongaro, Dufour-Décieux, Esch, Fritz, García, Hamann and Hondeborg2025). However, the downside of these liquid-based sorbents is that they are limited by their high-temperature requirements, synthetic methods, difficult regeneration processes and moisture sensitivity, which can restrain their CO2 capture ability in various climates (Wang et al., Reference Wang, Huang, Yang, Zhang, Wu, Gao, Wang, O’Hare and Zhong2014; Asim et al., Reference Asim, Badiei, Alghoul, Mohammad, Samsudin, Amin and Sopian2021; Ray et al., Reference Ray, Churipard and Peter2021).
In contrast, solid-based sorbents like zeolites, functionalized porous polymers and metal–organic frameworks (MOFs) are used without solvents. They can capture CO2 both physically and chemically (Halliday and Hatton, Reference Halliday and Hatton2021; Lee et al., Reference Lee, Kwon, Kim, Hwang, Choi, Park, Jamal and Koh2021; Shi et al., Reference Shi, Lee, Liu, Kim, Alahmed, Jamal, Wang and Park2023). MOFs are an intriguing class of nanocrystalline material that exhibit great potential in CO2 capture due to their high porosity and flexibility (Trickett et al., Reference Trickett, Helal, Al-Maythalony, Yamani, Cordova and Yaghi2017; Singh et al., Reference Singh, Lee, Karakoti, Bahadur, Yi, Zhao, AlBahily and Vinu2020; Guo et al., Reference Guo, Chu, Yuan, Otake, Yao and Kitagawa2025). The high tunability of MOFs has offered them a great opportunity in capturing CO2 gases selectively over other atmospheric gases (Liu et al., Reference Liu, Thallapally, McGrail, Brown and Liu2012; Dong et al., Reference Dong, Chen, Li and Qian2023; Zhao et al., Reference Zhao, Zhang, Li and Li2024). In comparison to liquid-phase DAC techniques that usually requires gas–liquid contactors, fans and heat-based regeneration systems (Dimitrijević et al., Reference Dimitrijević, Bösenhofer and Harasek2023; Lu et al., Reference Lu, Wang, Bhatti and Fan2023). Solid-based sorbents like MOFs can operate entirely under gas phase; this simplifies the overall procedure and reduces energy consumptions (Balogun et al., Reference Balogun, Bahamon, AlMenhali, Vega and Alhajaj2021; Halliday and Hatton, Reference Halliday and Hatton2021). These distinctive characteristics highlights the uniqueness in using solid-based MOFs in the advancement of the next-generation DAC sorbents by minimizing complexity while maintaining high CO2 capacity and selectivity that will lead to a new generation of material in DAC applications.
Over the last few decades, MOFs have garnered significant interest amongst inorganic chemists and crystal engineers. These types of materials are inorganic and organometallic polymeric compounds formed with the combination of organic ligands and metal clusters, producing 3D frameworks (Figure 1).
Simple illustration represented by the metal ions and organic linker molecules in the formation of MOFs. (Crystallography diagrams reproduced from (Li et al., Reference Li, Eddaoudi, O’Keeffe and Yaghi1999), (Lin et al., Reference Lin, Kong and Chen2016; Elorriaga et al., Reference Elorriaga, de la Cruz-Martínez, Rodríguez-Álvarez, Lara-Sánchez, Castro-Osma and García-Álvarez2021; Siegelman et al., Reference Siegelman, Kim and Long2021) (Self-produced).
Figure 1. Long description
The diagram is organized into three main horizontal sections.
1. Left Section (Building Blocks): At the bottom left, three silver spheres labeled Metal and three grey rods labeled Ligand combine. Above this, a blue tetrahedral cluster labeled M g, N i, F e etc. clusters points toward a dashed box containing three organic molecules: Terephthalic acid, Ethylenediamine, and 5-bromo-1,3-benzene dicarboxylate.
2. Center Section (Framework): An arrow leads to a 3D cubic lattice labeled Metal-Organic Frameworks. The lattice consists of silver spheres at the vertices and blue spheres inside the cubic voids. A dashed line points to a single blue sphere labeled Cavity.
3. Right Section (Categories): A large arrow points from the central framework to a dashed box titled Categories of M O F s. This box contains four molecular models, each with a corresponding arrow pointing to its complex lattice structure on the far right:
• Open-Metal Sites (O M S) leads to M O F-74, a red and blue hexagonal lattice.
• Amine-Functionalized leads to m m e n-M g sub 2 (d o b p d c), a green and red porous lattice.
• Fluorine-Functionalized leads to N b O F F I V E-1-N i, a rigid cubic green and blue lattice.
• Hydroxy-Functionalized leads to M I L-101, a large spherical red and blue cage structure.
One of the key characteristics of MOFs is well recognized by their extraordinary pore sizes, high porosity and the flexibility in tuning the surface area by changing the starting reagent materials (Stock and Biswas, Reference Stock and Biswas2012; Wu et al., Reference Wu, Xu, Li, Ma, Zhang, Liu, Fu and Wu2019; Cai et al., Reference Cai, Yan, Zhang, Zhou and Jiang2021). Their ability in tailoring their pore dimensionality and hierarchy and sizing by varying the selection of metal clusters, ligands, solvent and synthesizing methods. The formation of these ligand–metal linkages can lead to the generation of a range of coordination geometries (Hunter, Reference Hunter2023; Salehi et al., Reference Salehi, Esmailzadeh and Hassanzadeh-Afruzi2023; Singh et al., Reference Singh, Sivaram, Nath, Khan, Singh and Ramamurthy2024; Song and Ma, Reference Song and Ma2025). The innovation of the structural design in MOFs has raised significant attention in gas adsorption applications, particularly CO2 adsorption (Liu et al., Reference Liu, Thallapally, McGrail, Brown and Liu2012; Sun et al., Reference Sun, Liao, Zhao, Zhang, Liu and Shi2022).
Building upon these unique properties that MOFs can exhibit, the development of this type of sorbent material in the capture of CO2 gases, in particular DAC, has increased rapidly. The foundations of MOF chemistry were established through pioneering contributions by Prof. Richard Robson, Prof. Susumu Kitagawa and Prof. Omar M. Yaghi. The initial concept of MOFs was first developed by Robson in the 1980s, which demonstrated the potential of extended coordination frameworks. While Kitagawa and coworkers reported a porous coordination framework {[M₂(4, 4′-bpy)₃(NO₃)4]·xH2O}ₙ (M = Co, Ni, Zn), which retained its porous structure during gas adsorption and desorption without pores collapsing, thereby laying the foundation for subsequent studies of flexible MOFs or ‘soft-porous crystals’ (Kondo et al., Reference Kondo, Yoshitomi, Matsuzaka, Kitagawa and Seki1997). Furthermore, Yaghi proposed the concept of MOFs in the early 1990s and later reported MOF-5, which is regarded as the first MOF combining high structural stability, high surface area that has established the principles of reticular chemistry. These concepts of MOFs have inspired many other MOF design optimized for CO2 adsorption applications, including HKUST-1. Hence, these developments have accelerated their application in CO2 adsorption and separation (Chui et al., Reference Chui, Lo, Charmant, Orpen and Williams1999; Li et al., Reference Li, Eddaoudi, O’Keeffe and Yaghi1999; Kitagawa et al., Reference Kitagawa, Kitaura and Noro2004; Kobayashi et al., Reference Kobayashi, Mitsuka and Kitagawa2016; Bonneau et al., Reference Bonneau, Lavenn, Ginet, Otake and Kitagawa2020). Despite these advances, DAC remains a challenging process due to the dilute concentration of CO2 in the atmosphere at only ~400 ppm (0.04%) (McQueen et al., Reference McQueen, Gomes, McCormick, Blumanthal, Pisciotta and Wilcox2021; Chowdhury et al., Reference Chowdhury, Kumar, Shrivastava, Patel and Sangwai2023; Ali et al., Reference Ali, Shah, Karim, Hashmi, Ahmad, Habib, Sami and Abdullah2025). The low concentration of CO2 in the ambient air can make this process extremely difficult; therefore, sorbents designed for this application must demonstrate high selectivity and great working capacity. Traditional solid porous sorbent materials, such as activated carbons and zeolites, have limited the use in DAC applications due to their lack in tunability, low gas selectivity and strong adsorption competition with the presence of moisture in the air (Zhu et al., Reference Zhu, Xie, Wu, Miao, Xiang, Chen, Ge, Gan, Yang, Zhang, O’Hare, Li, Ge and Wang2022; Filahi et al., Reference Filahi, Assen, Ouikhalfan, Adil and Belmabkhout2025). Although DAC remains as an especially challenging process in the wide variety of applications that MOFs can exhibit (Figure 2). Their modular design in the high tunability of pore sizes, topologies, geometries, functionalities and chemistries can be altered specifically to trap and store a large quantity of CO2 through the selection of metals and ligands (Zhao et al., Reference Zhao, Timmons, Yuan and Zhou2011; Trickett et al., Reference Trickett, Helal, Al-Maythalony, Yamani, Cordova and Yaghi2017). This ability of high flexibility in MOF synthesis allows them to incorporate open-metal sites (OMS), polar functional groups and appended amines, these alternations has given MOFs the potential to act as a highly competitive sorbent candidate in the DAC applications (Wright et al., Reference Wright, Rieth, Yang, Wang and Dincă2018; Kong et al., Reference Kong, Yang, Chuai, Gao, Liu, Xuan and Xing2025).
Brief timeline of the development in MOFs and their desired applications (Self-produced).
Figure 2 Long description
Brief timeline of the development in MOFs and their desired applications. (Self-produced)
MOFs are highly configurable DAC materials. They can be produced not only through general synthesis methods but also post-synthetic procedures that enables functionalization that could be done during hydrothermal growth or post-chemical hydrothermal method. For instance, two frameworks so-called mmen-Mg2(dobpdc) and NbOFFIVE-1-Ni were generated through post-synthetic modifications procedures. Further, NH2-UiO-66 and MIL-101(Cr)-NH2 were synthesized through in situ linker functionalization processes. In addition, a variety of functionalization could be imported to further enhance fascinating properties of MOFs in exploring their ability in DAC applications (McDonald et al., Reference McDonald, Mason, Kong, Bloch, Gygi, Dani, Crocella, Giordanino, Odoh and Drisdell2015; Tchalala et al., Reference Tchalala, Bhatt, Chappanda, Tavares, Adil, Belmabkhout, Shkurenko, Cadiau, Heymans and De Weireld2019). First, amine-functionalized MOFs are widely being studied, their interaction with CO2 gases through chemical bonding in the formation of carbamate or bicarbonate ions, selectively under low-pressure environments (Patzschke, Reference Patzschke2014; Hamdy et al., Reference Hamdy, Goel, Rudd, Barron and Andreoli2021). Another well-recognized characteristic is the existence of OMS. The exposed metal centers can act as Lewis acids and strongly interact with the electrons on the CO2 (Chui et al., Reference Chui, Lo, Charmant, Orpen and Williams1999; Morris and Wheatley, Reference Morris and Wheatley2008; Sumida et al., Reference Sumida, Rogow, Mason, McDonald, Bloch, Herm, Bae and Long2012). The interaction between the metal and the CO2 can improve the overall gas uptake ability under diluted conditions in the atmosphere. Additionally, using hydrophobic and fluorinated organic linkers in MOF synthesis can reduce water adsorption competition with the CO2 gases and enhance the selectivity of CO2 (Amooghin et al., Reference Amooghin, Sanaeepur, Luque, Garcia and Chen2022; Venturi and Costantino, Reference Venturi and Costantino2023; Di et al., Reference Di, Yoshida, Otake, Kitagawa and Kitagawa2024). Different pore sizes of the MOF material can also be altered by the embodiment of a variety of cations to restrict the pore sizes of the framework, specifically for the CO2 molecules (Lau et al., Reference Lau, Babarao and Hill2013; Wright et al., Reference Wright, Rieth, Yang, Wang and Dincă2018; Ding et al., Reference Ding, Rong, Wang, Kong and Yao2023).
In this review, the state-of-the-art in MOF-based DAC sorbents are being examined. The synthesizing insights in the structural design and different functionalization strategies will also be summarized. Further, the advantages and critical challenges that these types of sorbent materials that remain in DAC applications will also be investigated. Finally, the future strategic research design and directions in designing an MOF with high scalability and durability are also outlined and suggested toward real-life DAC applications.
State-of-the-art of MOFs used in DAC applications
Recent developments in MOF chemistry have produced a range of frameworks targeted for DAC applications, including amine-functionalized MOFs, fluorine-functionalized MOFs, MOFs with OMS, hydroxy-functionalized MOFs and MOFs that contain hydrophobic and mixed-linker environments (Bhatt et al., Reference Bhatt, Belmabkhout, Cadiau, Adil, Shekhah, Shkurenko, Barbour and Eddaoudi2016; Britt et al., Reference Britt, Furukawa, Wang, Glover and Yaghi2009; Boone et al., Reference Boone, He, Lieber, Steckel, Rosi, Hornbostel and Wilmer2022; Mahajan and Lahtinen, Reference Mahajan and Lahtinen2022; Bose et al., Reference Bose, Sengupta, Malliakas, Idrees, Xie, Wang, Barsoum, Barker, Dravid, Islamoglu and Farha2023). These different types of MOF materials demonstrate the versatility of MOFs in addressing the challenging requirements of DAC applications, such as high selectivity under diluted CO2 concentrations, stability under humidity and the materials’ regenerability. The detailed description of each MOF design strategies with their representative examples, and benchmark performances in DAC applications will be outlined in the subsequent sections.
Amine-functionalized MOFs in DAC
Amine functional groups are widely recognized by their strong adsorption affinity toward CO2 from the atmosphere through the formation of carbamate and bicarbonate ions (Flaig et al., Reference Flaig, Osborn Popp, Fracaroli, Kapustin, Kalmutzki, Altamimi, Fathieh, Reimer and Yaghi2017). Even though chemisorptive interactions require much higher regeneration energies than physiorptive adsorbents, incorporating amines into porous materials has enhanced the overall CO2 uptake efficiency and increased the stability of the sorbent material under ultradiluted conditions (Hack et al., Reference Hack, Maeda and Meier2022; Sekizkardes et al., Reference Sekizkardes, Wang, Hoffman, Budhathoki and Hopkinson2022; Duan et al., Reference Duan, Song, Lu, Wang, Sun, Chen and Xie2023). With the advantages of their high surface areas, tunability and flexibility, amine functional groups were able to be introduced into well-defined environments. The highly ordered pore structures of the MOFs allow efficient mass transport and precise control in amine density, therefore overcoming the limitations associated with the traditional liquid amine sorbents. Furthermore, moderate humidity can promote the formation of bicarbonate and improve amine utilization, potentially allowing the capture of one CO2 molecule per amine group (Lin et al., Reference Lin, Kong and Chen2016; Sharp et al., Reference Sharp, Bukowski, Li, Johnson, Ilic, Morris, Gersappe, Snurr and Morris2021; Sher et al., Reference Sher, Hayward, El Guerraf, Wang, Ziani, Hrnjić, Boškailo, Chupin and Nemţanu2024).
Several approaches have been developed to introduce amine groups into the porous frameworks through post-synthetic grafting onto the OMS, impregnation of polymeric amines and direct incorporation of amine-functionalized ligands, such as polyethyleneimine (PEI), can directly influence the CO2 adsorption capability of the materials (Lin et al., Reference Lin, Kong and Chen2016; Chen and Zhao, Reference Chen and Zhao2023; Khan et al., Reference Khan, Samuel, Othman, Younas, Kamaludin, Puteh, Kurniawan, Wong, Kadirkhan and Yoshida2024; Ray et al., Reference Ray, Churipard, Cherevotan, Deka, Goud, Kopperi and Peter2024; Sher et al., Reference Sher, Hayward, El Guerraf, Wang, Ziani, Hrnjić, Boškailo, Chupin and Nemţanu2024).
Some as synthesized representative MOFs, including the diamine-appended mmen-Mg2(dobpdc) were reported by McDonald et al. This framework was synthesized by expanding the terephthalic acid to create M-4,4′-dioxido-3,3′-biphenyldicarboxylate (M-DOBPDC, M = Mg, Mn, Ni, Fe, Co and Zn) frameworks (Figure 1) (McDonald et al., Reference McDonald, Lee, Mason, Wiers, Hong and Long2012; Martell et al., Reference Martell, Milner, Siegelman and Long2020; Lin et al., Reference Lin, Xie, Hong and Jiang2023). This diamine-appended MOF material exhibits a cooperative adsorption mechanism with a step-shaped isotherm ideally suited for low partial pressured CO2 capture, achieving an equilibrium uptake of ~2.0 mmol/g at 25 °C and ~390 ppm in simulated air. Kinetic studies showed the adsorbent material achieves a near 100% regeneration ability at 120 °C and no observable degradation over 10 consecutive adsorption–desorption cycles under ambient conditions (McDonald et al., Reference McDonald, Lee, Mason, Wiers, Hong and Long2012; Martell et al., Reference Martell, Milner, Siegelman and Long2020; Lin et al., Reference Lin, Xie, Hong and Jiang2023).
Likewise, another representative amine-functionalized MOF were UiO-66 and UiO-67 derivatives exhibiting a CO2 uptake of 0.2–0.5 mmol/g under ~400 ppm at 298 (Tian, Reference Tian2023; Zhang et al., Reference Zhang, Zhao, Yang, Yao, Wu and Gu2023). Post-synthetic grafting of monoethanolamine onto the UiO-66 frameworks has increased the CO2 capacity to 0.8 mmol/g at 0.15 bar and 298 K, while maintaining great hydrolytic stability. (Abdelnaby et al., Reference Abdelnaby, Tayeb, Alloush, Alyosef, Alnoaimi, Zeama, Mohammed and Onaizi2024).
Furthermore, the amine-modified MIL-101(Cr) using ED (ethylenediamine), diethylene triamine and diaminodipropylamine reported by Yang et al. highlighted the utility of OMS for robust amine anchoring (Yang et al., Reference Yang, Cheng, Yao, Li and Yang2024). They observed the highest CO2 uptake capacity was 2.0 mmol/g at 0.15 bar and 298 (Xi et al., Reference Xi, Dong, Li, Lu, Pan, Liu and Qiao2025) Lin et al. have further studied the loading with PEI in MIL-101(Cr) using PEI-300, PEI-1800 and PEI-100000, and discovered the loadings with PEI-300 have demonstrated the highest CO2 uptake capacity of 4.2 mmol/g at 0.15 bar CO2 under 298 (Lin et al., Reference Lin, Lin, Wang, Suo, Li, Kong and Chen2014). In comparison to benchmark sorbents like zeolites and activated carbons, the amine-functionalized MOFs have reached a comparable gas capacity uptake surpassing 2 mmol/g at ~400 ppm (Fu et al., Reference Fu, Park and Davis2022).
Under realistic DAC conditions, amine-functionalized MOFs are considered as one of the more effective adsorbent materials. Their strong chemisorptive interactions with CO2 molecules under low partial pressures outstands other physisorbed adsorbents based on OMS. The presence of humidity in the atmosphere can also enhance the adsorption capability of certain amine-based materials through bicarbonate formation and hence improving amine utilizations (Elorriaga et al., Reference Elorriaga, de la Cruz-Martínez, Rodríguez-Álvarez, Lara-Sánchez, Castro-Osma and García-Álvarez2021; Siegelman et al., Reference Siegelman, Kim and Long2021). However, the downside of this modified material is excessive loading of amines can increase the material’s regeneration energy and induce oxidative degradation during prolonged exposure to oxygen and moisture environments. However, amine-functionalized MOFs are classified as one of the most intriguing adsorbent type in moisture-tolerance and regenerability in DAC applications (Lin et al., Reference Lin, Kong and Chen2016).
Fluorine-functionalized MOFs in DAC
Fluorinated MOFs have emerged as a highly promising candidate for physisorbents in DAC applications due to their strong CO2 affinity and hydrophobic pore environments (Venturi and Costantino, Reference Venturi and Costantino2023). The incorporation of fluorine functional groups into the frameworks through either inorganic fluorinated pillars (SiF₆2−, TiF₆2− and NbOF₅2−) and via partially or fully fluorinated organic ligands, helps the frameworks to create polar pore environments that can interact with the quadrupole moments of CO2 and enhance the overall framework hydrophobicity simultaneously (Bhatt et al., Reference Bhatt, Belmabkhout, Cadiau, Adil, Shekhah, Shkurenko, Barbour and Eddaoudi2016; Belmabkhout et al., Reference Belmabkhout, Zhang, Adil, Bhatt, Cadiau, Solovyeva, Xing and Eddaoudi2019; Guimarães and de Lima, Reference Guimarães and de Lima2020).
Among all the fluorinated MOFs, the most widely studied are the SIFSIX and the TIFSIX series. Their hexafluorometallate anions act as pillars between the metal–pyrazine-based layers, forming micropores that are selectively suitable for CO2 gases over O2 and N2 (Elsaidi et al., Reference Elsaidi, Mohamed, Helal, Galanek, Pham, Suepaul, Space, Hopkinson, Thallapally and Li2020; Guimarães and de Lima, Reference Guimarães and de Lima2020). For example, SIFSIX-3-Cu exhibits a gas uptake capacity of 1.24 mmol/g at 400 ppm CO2 under 298 K, with a Qst value of 54 KJ/mol and it is higher than the values in most MOFs. Resulting from strong interactions between the electropositive CO2 molecules and the electronegative fluorine sites (Forrest et al., Reference Forrest, Pham and Space2017; Bayati et al., Reference Bayati, Keshavarz, Rezaei, Zendehboudi and Barbiellini2024). The framework also demonstrated good cyclic stability while maintaining minimal capacity loss over repeated adsorption–desorption cycles. However, the presence of humidity remains as a critical challenge for this type of MOF. Water molecules, with a kinetic diameter of 2.65 Å, can compete with the adsorption of CO2 under realistic atmospheric conditions, thereby blocking CO2 adsorption and hinders its regeneration ability (Kanehashi et al., Reference Kanehashi, Chen, Ciddor, Chaffee and Kentish2015; Zhao et al., Reference Zhao, Deng, Zhao, Yuan, Wang, Chen and Wu2021).
Similarly, an MOF known as the NbFFIVE-1-Ni demonstrated great DAC performances, exhibiting a CO2 uptake of ~1.3 mmol/g at 400 ppm in 298 K under both short- or long-term humid and dry conditions (Bhatt et al., Reference Bhatt, Belmabkhout, Cadiau, Adil, Shekhah, Shkurenko, Barbour and Eddaoudi2016; Cadiau et al., Reference Cadiau, Adil, Bhatt, Belmabkhout and Eddaoudi2016). Another advantage is the high cyclic stability of the material after multiple adsorption–desorption cycles, with less than 2% capacity loss after 2000 adsorption–desorption cycles (Guo et al., Reference Guo, Wu, Lv, Meng, Yun, Jin and Mi2021). Although the introduction of fluorine functional groups can enhance the enthalpic affinity in CO2 capture, prolonged exposure to moisture can induce hydrolysis and compromise long-term material stability, resulting a slower mass-transfer kinetics. In addition, large scale of synthesizing F-rich MOFs remains challenging due to the high material costs and the danger that maintains in fluorine handling. Nevertheless, PFAS can be formed during the manufacturing processes of fluorine-based MOFs. In particular, if perfluoroalkane-functionalized precursors and fluoropolymer additives were involved in the synthetic procedure. The solvent-intensive or high-temperature conditions incorporated into MOF synthesis will also lead to the release of fluorinated compounds and the degradation of materials into PFAS contaminants (Sanzana et al., Reference Sanzana, Fenti, Iovino and Panico2025).
Under realistic DAC environments, fluorinated MOFs has the ability in providing a favorable balance between the resistance in moisture and CO2 affinity. Hence, allowing them to become a more humid tolerant material in comparison to many conventional physisorbents. In comparison with amine-functionalized MOFs, fluorine-based MOFs exhibit lower adsorption capacities under DAC related conditions, as they solely rely on physisorption rather than chemisorption processes (Elsaidi et al., Reference Elsaidi, Mohamed, Helal, Galanek, Pham, Suepaul, Space, Hopkinson, Thallapally and Li2020; Guimarães and de Lima, Reference Guimarães and de Lima2020). However, the advantage is these materials require a lower regeneration energy and adopt a faster adsorption kinetics. As a result, fluorine-functionalized MOFs are generally attractive in DAC applications due to their humidity tolerance, rapid cycling and lower regeneration energy requirements; however, environmental concerns relating with fluorinated compounds remain as a crucial challenge (Cadiau et al., Reference Cadiau, Adil, Bhatt, Belmabkhout and Eddaoudi2016; Strieth-Kalthoff and Glorius, Reference Strieth-Kalthoff and Glorius2020).
In comparison to the amine-functionalized MOFs, the fluorinated adsorbents are more favorable in environments that contain moderate humidity and the highlight of its low regeneration energy constraints. While amine-based MOFs are superior in achieving high working capacities under diluted CO2 environments.
MOFs with open-metal sites in DAC
MOFs with open-metal sites (OMS) are another category of important class of adsorbents for CO2 capture. These adsorbents contain coordinately unsaturated metal ions that act as Lewis acid sites, enabling strong electrostatic interactions with the negatively charged oxygen atoms of the CO2 molecules. In comparison to N2, CO2 exhibit stronger quadrupole moment and polarizability, which can lead to a stronger interaction with the Lewis acidic OMS.
A representative example is HKUST-1 (Cu-BTC), which contains high density of accessible copper ion sites. This material exhibited a generally high CO2 uptake capacity of around 3.2 mmol/g of CO2 uptake at 273 K and 1 bar under ambient conditions, with higher capacities reported upon structural optimization (Chui et al., Reference Chui, Lo, Charmant, Orpen and Williams1999). The adsorption arises via direct coordination of the CO2 molecules to the Cu sites with the combination of pore-confinement effects. Likewise, Cu-BTC and frameworks containing OMS contain a faster adsorption kinetics due to their strong and accessible binding sites, thereby allowing fast equilibration under diluted CO2 conditions (Yan et al., Reference Yan, Zhang, Grisdanurak, Wibowo, Yu and Kanchanatip2023).
Another group of OMS–MOFs is the M-MOF-74 series (M = Mg2+, Ni2+, Co2+ and Zn2+). In particular, the M-MOF-74 series has been studied extensively due to the alignment of its one-dimensional channels with the accessible metal sites, which enables an extremely high site density that is available for CO2 binding (Figure 1). Among this series, the requirement of Mg-MOF-74 material regeneration temperature was relatively low at around only 80 °C, which is an advantage compared to the conventional amine-based sorbents that requires a slightly higher regeneration temperature up to 100–120 °C (Ling et al., Reference Ling, Zhou, Wang, Jia, Ma and Li2022). However, substituting the metals with Ni and Co can reduce the uptake capacity while maintaining high gas selectivity and material stability.
Despite these advantages, the OMS-based MOFs provided in CO2 adsorption, their general adsorption performance would reduce under realistic DAC conditions, primarily due to competition with moisture of adsorbing water molecules. Moisture can bind to the OMS strongly and block the accessible binding sites to the CO2, thereby reducing the overall working capacity under humid air environments (Liu et al., Reference Liu, Ning, Zheng, Tao, Shi and He2013). The water sensitivity is classified as one of the major limitations in OMS-based adsorbents in DAC applications.
In addressing this issue, there are various stability-enhancing strategies have been developed. For example, the polymer-protected [Mg₂(dobdc)(DMF)₂]@polystyrene has shown almost unchanged CO2 uptake capacity even after exposure to 90% humidity, demonstrating the maintenance of the CO2 adsorption even under high-humidity conditions. This approach has highlighted the importance of pore engineering and surface modification in the improvement of material’s stability under realistic DAC conditioned environments (Moon et al., Reference Moon, Moon, Chun, Park, Yun, Sohail, Baek and Kim2016).
Overall, MOFs with OMS exhibit strong CO2 binding ability and fast adsorption kinetics under low-pressure conditions. However, when compared to amine-functionalized MOFs, its adsorption performance under diluted CO2 conditions is strongly affected by humidity due to its competitive water coordination with the metal ions. Although this type of adsorbent is a promising candidate in CO2 adsorption due to their fast kinetics and good regeneration energy, consequently, their practical DAC performance can be dependent on mitigating water adsorption on the center metal ion sites.
Hydroxy-functionalized MOFs in DAC
Hydroxy-functionalized MOF are a prominent class of physisorbent materials that are growing extensively in DAC applications. Hydroxy functional groups (-OH), either acting as an organic linker or bridging moieties on the metal centers, can enhance CO2 uptake via hydrogen bonding and polar interactions while maintaining structural robustness under moisture conditions (Piscopo and Loebbecke, Reference Piscopo and Loebbecke2020; Gu et al., Reference Gu, Liu, Wang, Liu and Hu2021).
A representative example is known as the MOF-74 series, where hydroxy-containing linkers and exposed metal sites create a high-density adsorption environment that can interact with CO2 molecules. Mg-MOF-74 exhibits a high uptake of ~7.9 mmol/g at 298 K and 1 bar, although its adsorption performance decreases to 0.088 mmol/g under DAC conditions (0.04 mbar), highlighting the challenges in translating from high-pressure testing conditions to ultradiluted environments (Qasem et al., Reference Qasem, Abuelyamen and Ben-Mansour2021; Ma et al., Reference Ma, Zhou, Hong, Jia and Liu2023). To overcome this limitation, functionalization modification of using ethylenediamine into the Mg-MOF-74 frameworks has yielded the ED@MOF-74. This modification has enhanced low-concentration performance up to ~1.8 mmol/g under moisture 400 ppm conditions, with enhanced breakthrough behavior and faster regeneration kinetics (Ben-Mansour et al., Reference Ben-Mansour, Qasem and Habib2018; Qasem and Ben-Mansour, Reference Qasem and Ben-Mansour2018; Mahajan et al., Reference Mahajan, Elfving and Lahtinen2024).
Similarly, UiO-66-derived hydroxy-functionalized MOFs introduced additional hydrogen-bonding sites that can enhance CO2 affinity, for example, UiO-66-(OH)2. Although low-concentration (~400 ppm) breakthrough tests are limited, past literature has tested that the material can adsorb 4.65 mmol/g (parent UiO-66) of CO2 at 273 K to 7.25 mmol/g (hydroxy-functionalized) under the same experimental conditions (Rada et al., Reference Rada, Abid, Shang, Sun, He, Webley, Liu and Wang2016). Although these uptake values are tested under higher pressures compared to DAC conditions, highlighting the role of polar pore environments in strengthening of CO2 interactions.
MIL-101(Fe) and PCN-61(Al) further illustrate the advantages of hydroxy-functionalized material in gas adsorption. MIL-101(Fe), with trimeric Fe3O clusters bridged by the μ₂-OH groups can adsorb up to 3.8 mmol/g under the conditions of 298 K and 1 bar under cyclic humid conditions, along with relatively fast adsorption–desorption cycling behavior (Figure 1) (Mutyala et al., Reference Mutyala, Jonnalagadda, Mitta and Gundeboyina2019; Mahdipoor et al., Reference Mahdipoor, Halladj, Babakhani, Amjad-Iranagh and Ahari2021; Jolodar et al., Reference Jolodar, Abdollahi, Fatemi and Mansoubi2024). Another representative example is the PCN-61(Al), containing high density of μ₃-OH groups exhibits a reasonably high CO2 affinity of 3.2 mmol/g in the same conditions. (Liu and Yu, Reference Liu and Yu2018) GCMC and DFT studies indicated that the presence of hydroxy-metal clusters can generate high-affinity binding pockets and hence increase the material’s kinetics’ rate (Tao et al., Reference Tao, Zhang and Xu2022).
Collectively, hydroxy-functionalized MOFs have illustrated promising advantages in the gas uptake capability in DAC sorbent design. The improvements in water tolerance compared with purely hydrophobic physisorbents. However, under realistic DAC conditions, their CO2 uptake is much lower than the amine-functionalized MOFs, which solely relies on strong chemisorptive interactions. There are also challenges that remain in the OMS–MOFs, including high selectivity and maintaining stability under realistic atmospheric operating conditions, remain underexplored. In particular, the hydroxy groups can decompose at elevated temperatures, which can therefore result in a structural instability and decrease the overall adsorption performance. Under realistic DAC conditions, the hydroxy-functionalized MOFs demonstrate a moderate performance due to their physisorption-dominated binding ability; however, it is much weaker in comparison to the chemisorptive amine-based systems.
MOFs that contain hydrophobic and mixed-linker environments in DAC
MOFs that contain hydrophobic and mixed-linker systems have garnered wide attention due to their high gas-capturing performance under both humid and ambient conditions (Xie et al., Reference Xie, Xu, Liu, Zhao and Li2020; Gu et al., Reference Gu, Yuan, Qadir, Yuan, Zhao, Sun, Liu and Wang2022; Shi et al., Reference Shi, Lee, Liu, Kim, Alahmed, Jamal, Wang and Park2023). These materials are promising for DAC applications, at which water competition under ultradilute CO2 concentrations strongly influences the material’s adsorption behavior (Shi et al., Reference Shi, Huang, Qi, Su and He2020; Akai et al., Reference Akai, Kasai and Oka2025; Gebremariam et al., Reference Gebremariam, Varghese, Kuppireddy, Al Wahedi, AlHajaj, Karanikolos and Dumée2025).
Hydrophobic functionality is introduced through fluorinated linkers or surface-protection strategies, such as core–shell coatings, in which reduces water adsorption and allowing more accessible CO2 binding sites. For example, the NbOFFIVE-1-Ni fluorinated MOF exhibits an uptake of ~1.3 mmol/g under 400 ppm and 298 K while maintaining strong moisture tolerance and high gas selectivity under humidity (Figure 1) (Bhatt et al., Reference Bhatt, Belmabkhout, Cadiau, Adil, Shekhah, Shkurenko, Barbour and Eddaoudi2016). Additionally, hybrid core–shells architectures such as ZIF-8, are grown around the HKUST-1 core. This can enhance the moisture stability of the sorbent and retain its excellent CO2 uptake ability of ~2.9 mmol/g under 1 bar, this hence highlights the benefit of surface hydrophobic protection around the MOFs in water-rich environments (Gebremariam et al., Reference Gebremariam, Varghese, Kuppireddy, Al Wahedi, AlHajaj, Karanikolos and Dumée2025). In comparison to the hydrophobic uncoated material of the HKUST-1 sorbent, the modified sorbent showed improved performance, which highlights the potential of inserting hydrophobic coatings into MOFs toward real-world DAC applications.
In contrast, mixed-linker MOFs are synthesized by combining different organic linkers into the same framework in optimizing the pore structure, functional groups and the overall adsorption capability. This synthetic strategy can allow the framework to tune specifically toward CO2 adsorption capacity, stability and selectivity. For example, a representative example containing mixed-linker with both the hydrophobic and amine-functionalized groups known as UiO-66(Zr)-NH2-F4-0.53 exhibits ~0.76 mmol/g under 15% CO2/85% N2 experimental conditions at 298 K and under a condition containing 70% humidity (Hu et al., Reference Hu, Gami, Wang and Zhao2017; Ge and Ma, Reference Ge, Ma, Jiang, Mahurin and Dai2020). This MOF is a good representative sorbent material that can both maintain a high adsorption uptake capacity and adopt a strong resistance to moisture interference. Although these conditions are higher than DAC CO2 concentrations, the improvement in the CO2 capacity highlights the material’s resistance to moisture interference compared to single-functionalized frameworks.
Overall, MOFs that contain hydrophobic and mixed-linker environments can enhance the materials’ stability and CO2 uptake capacity. It is also crucial to synthesize a material in balancing the surface area, pore size and functional group density. Recent developments in hybrid coatings and mixed-linker synthesis will improve the ability of adsorption in MOFs for DAC applications, as these synthetic methods can allow the material to achieve a high CO2 gas selectivity and low moisture sensitivity. However, under real DAC conditions, their performance is significantly garnered by their physisorption strength, which is lower than that of the chemisorptive amine-based MOFs. Consequently, these types of materials are classified as stabilized physisorbents, in which offering an obvious improvement of durability in humid environments but somewhat moderate CO2 affinity in comparison to the stronger-binding gas adsorption sites (Table 1).
Summary table outlining all the MOFs used for CO2 adsorption classified into their different experimental conditions
Table 1. Long description
Summary table outlining all the MOFs used for CO2 adsorption classified into their different experimental conditions
To summarize these unique functionalities in MOF design under DAC conditions, the overall adsorption performance of MOF functionalization is heavily dependent on the dominant adsorption mechanism and their effects with moisture competition. Amine-functionalized MOFs generally exhibit the highest CO2 uptake capacity under ultradiluted concentrations due to the chemisorptive bicarbonate and carbamate formation, but the requirement of the higher regeneration energy can be a main challenge, and their suffer from long-term oxidative stability problems. On the other hand, MOFs with OMS provide strong Lewis acid–base interactions and faster kinetics. However, their competition with moisture reduces their working capacity under humidity environments. Fluorinated MOFs offer better humidity tolerance due to their hydrophobic pore environments, but their lower CO2 adsorption capacity is the main problem caused by their physisorption-driven mechanism. Further, MOFs that contain hydroxy- and mixed-linkers provide intermediate performance, their improvements in the CO2 affinity through hydrogen-bonding interactions remained less effective compared to the amine-based systems under DAC conditions. Finally, hydrophobic and core–shell engineered MOFs priorities water resistance and cycling stability but exhibiting a consequence of adsorption strength with the CO2 molecules. Overall, there are no single functionalization strategy in MOF synthesis that is universally optimal, the high CO2 uptake performances is governed by trade-off in humidity tolerance, stability, regeneration energy and the strength of CO2 interactions under specific DAC operating systems.
Conclusions and future perspectives
MOFs have emerged as one of the most promising classes of porous materials in DAC applications. In comparison to other traditional sorbents such as activated carbons and zeolites, their high structural tunability and surface area can offer adjustable pore sizes that can mainly target CO2 molecules while maintaining high structural stability. Amine-functionalized MOFs, including mmen-Mg₂(dobpdc) and PEI-loaded MIL-101(Cr), showed high CO2 capacity ranging from ~2 to 4 mmol/g under low CO2 concentration conditions. Their fast adsorption kinetics and great cycle stability dominated them as strong candidates in DAC applications. Fluorine-functionalized MOFs, such as SIFSIX-3-Cu and NbFFIVE-1-Ni can provide high binding affinity to CO2 gases under moisture conditions, although fluorine-handling could still be an issue that remain as a challenge in these types of MOF sorbents. Further, MOFs with OMS such as Mg-MOF-74, HKUST-1 and Cu-BTC exhibit strong electrostatic interactions with CO2 and high isosteric heats of adsorption. With Mg-MOF-74 obtaining the highest working capacities of ~6 mmol/g at 298 K and 1 bar and a relatively low material regeneration temperature (~80 °C). Hydroxy-funtionalized MOFs, for example, the MOF-74(OH), UiO-66-(OH)₂, MIL-101(Fe), PCN-61(Al) and Zn(ZnOH)₄(bibta)₃. These materials can enhance CO2 binding through hydrogen-bonding interactions while maintaining structural robustness in moisture conditions. Nevertheless, MOFs containing hydrophobic ligands and mixed-linker systems such as the ZIF-8@HKUST-1 and UiO-66(Zr)-NH₂-F₄, balancing water resistance, CO2 gas selectivity and pore accessibility can offer great potential toward real-life DAC applications.
Considering all the MOF sorbent materials discussed in this review, mmen-Mg₂(dobpdc) and Mg-MOF-74 have emerged as the most attractive benchmarked sorbent candidates for DAC applications under low ambient CO2 partial pressures. Their high uptake capacity, fast kinetics rate and operational stability overtake other MOF functionalization thus providing complementary advantages such as moisture tolerance and further enhancement in CO2 gas selectivity.
Despite all the advances provided by MOF sorbents in DAC applications, there are still several challenges that remain. Maintaining the structural stability and recyclability of this type of sorbent material under humid conditions remains a major concern, particularly for functionalized frameworks. Additionally, producing MOFs at larger scales often requires energy-intensive processes and much more complex synthetic procedures; therefore, the limitations in commercial viability for this type of sorbent remains unsolved. Moreover, the reliance on expensive organic linkers, hazardous solvents and much more energy-intensive synthetic methods requires additional challenges in large-scale production of the material, hence highlighting the need for a much greener and scalable synthetic methods. Furthermore, many MOFs are tested and reported under idealized conditions, whereas real-life DAC atmospheric conditions involve fluctuating humidity, which could significantly affect the performances of the MOF sorbents. Concurrently, the repeated stability in the adsorption–desorption cycles of the materials is also unknown. Consequently, long-term cyclic stability and regeneration energy of the sorbent under realistic DAC conditions require further testing and investigations.
Future functionalization strategies should broaden their focus to encompass wider perspectives. Apart from maximizing the sorbent’s CO2 uptake, it is also important to maintain the material’s adsorption strength, their moisture tolerance, regeneration energy, adsorption kinetics and its cyclability. In addition, mixed-metal frameworks, hybrid functionalization strategies in combining hydrophobic environments, OMS and tailoring functional groups can provide improvements in the sorbents toward CO2 affinity and selectivity. Computational screening, data-driven materials recovery and machine leaning can also accelerate the identification of high-performing adsorbents that obtain both high adsorption capacity, stability and good energy efficiency.
Finally, from a practical perspective, transforming powder MOF materials into mechanically robust pellets or monoliths without optimizing the porosity and damaging the material’s original capability remains a major challenge in MOF-relevant sorbent materials under DAC conditions. Future efforts should therefore input into the materials’ design with adsorption process engineering to improve the heat and mass transfer properties of the material to facilitate in large-scale material productions. Additionally, compatibility with industrial adsorption processes and the preservation of the material’s performance during the adsorption process and scaling-up procedure will also be important toward successful commercialization. It is also worth noting that the techno-economic analysis and material’s cyclic assessments, including the material’s overall energy consumption, cost-effectiveness and environmental impact should be evaluated in the next-generation MOF sorbents. Moreover, the adsorption capacity does not alone determine the industrial viability of the material, such as the working capacity, regeneration energy and the cyclability, therefore, on-going usage of the adsorbent must take into consideration to further evaluate the economic feasibility in real-life DAC applications.
Overall, by combining the engineering considerations, adsorption performances and the scalability of the adsorbents, MOFs are a crucial sorbent material in sustainable DAC applications and can significantly contribute to the improvements of global warming affected by climate change (Table 2).
Summary table of some of the most promising strategies in designing MOFs used in DAC applications
Table 2. Long description
Summary table of some of the most promising strategies in designing MOFs used in DAC applications
Open peer review
To view the open peer review materials for this article, please visit http://doi.org/10.1017/cat.2026.10015.
Author contribution
Yuying Feng wrote and edited the original draft of the manuscript, made the diagrams and tables in the manuscript.
Lei Dong gave advisory and edited the final version of all diagrams.
Ali Zavabeti and Adrian Loy Chun Minh gave suggestions in the correction of the manuscript, supported the fundamental studies of the research and supervision of the study.
Gang Li gave suggestions to the manuscript, provided supervision of the study, provided funding support and edited the manuscript.
Competing interests
The authors declare that there is no conflict of interest in this study.
Data availability statement
The datasets generated during and/or analyzed during the current study are available in the main manuscript.
Funding statement
Funding for this research was provided by the Clean Energy Lab in the University of Melbourne under the Chemical Engineering Department, supported by the University funding provided by A/Prof Gang Li.
Open access
Comments
A/Prof. Gang Kevin Li
Department of Chemical Engineering
The University of Melbourne
Parkville VIC 3010
Melbourne, Victoria, 3000
Email: li.g@unimelb.edu.au
Date: 10 March 2026
To:
Prof. Jin Shang
Co-Editor-in-Chief
Cambridge Prisms: Carbon Technologies
Subject: Cover Letter for Invited Review Article Submission — “Metal-Organic Frameworks (MOFs) Functionalization for Direct Air Capture”
Dear Prof. Shang,
I am writing in response to your kind invitation to submit a manuscript to Cambridge Prisms: Carbon Technologies. Please find enclosed our invited review article entitled “Metal-Organic Frameworks (MOFs) Functionalization for Direct Air Capture”, which we are pleased to submit for consideration in your journal.
This review discusses the emerging role of Metal-Organic Frameworks (MOFs) in advancing Direct Air Capture (DAC)technologies, which are critical for achieving carbon neutrality. Specifically, the article:
(a) outlines the most recent developments of MOFs designed for DAC applications;
(b) provides a comprehensive review of key MOF classes—hydroxy-rich, amine-functionalized, and those featuring open-metal-sites (OMS)—that contribute to enhanced CO₂ capture efficiency; and
(c) presents insights into the current challenges and future directions for developing MOFs that are cost-effective, high-performing, and durable for real-life DAC implementation.
We believe this review will be of particular interest to readers of Cambridge Prisms: Carbon Technologies, as it offers a timely and in-depth overview of MOF functionalization strategies for sustainable carbon capture.
All authors have read and approved the final version of this manuscript and confirm that it has not been published elsewhere and is not under consideration by any other journal. We sincerely appreciate the opportunity to contribute to Cambridge Prisms: Carbon Technologies and look forward to your consideration of our submission.
Thank you very much for your time and attention.
Sincerely,
A/Prof. Gang Kevin Li
Department of Chemical Engineering
The University of Melbourne
Email: li.g@unimelb.edu.au