The Chemistry and Applications of Metal-Organic Frameworks

Imagine a material with the surface area of an entire football field packed into a piece the size of a sugar cube. A material that can selectively trap carbon dioxide from power plants, store hydrogen for clean transportation, separate valuable chemicals, deliver medicines inside the human body, and even remove water from desert air.

This seemingly impossible material exists. It belongs to a class of compounds called metal–organic frameworks (MOFs), one of the most influential discoveries in modern materials science.

Among the thousands of papers published on MOFs, the paper published by Hiroyasu Furukawa, Kyle Cordova, Michael O’Keeffe, and Omar Yaghi in 2013, “The Chemistry and Applications of Metal-Organic Frameworks,” remains the most influential [1].

Rather than introducing a single new material, this paper summarized decades of research while establishing a roadmap for where the field was headed. It unified knowledge about MOF chemistry, highlighted emerging applications, and inspired researchers across chemistry, engineering, energy, medicine, and environmental science [1].

What Are Metal–Organic Frameworks?

Metal–organic frameworks are crystalline materials built from two simple components [2]:

• Metal ions or metal clusters that act as joints

• Organic molecules (linkers) that connect the joints together

Furukawa et al. outlines the most important advances in MOFs as [1]:

1. Secondary Building Units (SBUS): Linking metal-containing units with rigid shapes like squares and octahedra (SBUs) instead of using single metal atoms allowed researchers to build predictable, stable framework structures with permanent porosity.

2. Isoreticular Design: Scientists could enlarge or modify MOFs while keeping the same underlying framework, leading to materials with ultrahigh surface areas and much larger pores.

3. Postsynthetic Modification (PSM): MOFs can be chemically modified after synthesis by adding new functional groups or metal complexes, enabling applications such as catalysis and tailored chemical reactivity.

4. Multivariate MOFs (MTV-MOFs): Multiple different functional groups can be incorporated into a single MOF, creating more complex and customizable pore environments for specialized applications.

Extremely High Surface Area and Porosity

Surface area determines how many molecules a material can interact with.

Traditional porous materials already possess impressive surface areas, but MOFs push this idea even further [2][3].

Expansion of Structures

One of the most transformative advances is the concept of isoreticular expansion—systematically enlarging MOFs while preserving their underlying crystal topology. 

Beginning with the IRMOF series, researchers demonstrated that simply replacing organic linkers with longer or functionalized versions could expand a framework by factors of 2 to 17 without changing its overall architecture. This strategy greatly increased pore size and internal volume, creating materials with exceptional gas storage and separation capabilities. The paper also shows that careful selection of crystal topology is essential for preventing interpenetration. 

Using this design principle, researchers developed record-breaking materials such as MOF-399, whose unit cell is 17.4 times larger than HKUST-1 and possesses an extraordinary 94% void fraction, illustrating how rational structural design enables MOFs with unprecedented porosity, ultralow density, and highly tunable properties for a wide range of applications.

Exceptionally Large Pores

The development of expanded-pore MOFs capable of hosting much larger molecules than conventional frameworks was another notable advancement of MOFs. 

Most MOFs have pore openings smaller than 2 nm, limiting them to small gas molecules, but researchers overcame this by using infinite rod-shaped secondary building units (SBUs) combined with progressively longer organic linkers to create the IRMOF-74 series. 

This increased pore apertures from 14 Å to 98 Å while preventing interpenetration, producing channels large enough for intact proteins such as green fluorescent protein (GFP) to enter without unfolding. 

The expanded pores also allowed scientists to modify the pore surfaces with different chemical functionalities—for example, attaching oligoethylene glycol groups enabled the inclusion of myoglobin, whereas hydrophobic modifications largely prevented protein uptake. This demonstrated that MOFs could be engineered not only with larger pores but also with customizable chemical environments for applications in biotechnology, catalysis, and molecular separations.

Thermal and Chemical Stability

A major challenge in developing practical MOFs has been achieving high thermal and chemical stability, since many early frameworks degraded when exposed to moisture, solvents, or harsh chemical environments. The paper highlights several breakthroughs that overcame this limitation, including ZIF-8, which remained stable after days in boiling water, methanol, benzene, and even concentrated sodium hydroxide, and UiO-66, a zirconium-based MOF resistant to both strongly acidic (pH 1) and strongly basic (pH 14) conditions.Other highly robust MOFs, such as MOF-525, MOF-545, and Ni₃(BTP)₂, maintained their structures under prolonged exposure to water and extreme pH. 

These advances demonstrated that MOFs could withstand the demanding conditions required for real-world applications, particularly carbon capture from humid flue gases, catalysis, and other industrial processes involving water and harsh chemicals.

Carbon Capture

Perhaps the most exciting application discussed in the paper involves capturing carbon dioxide before it reaches the atmosphere.

Power plants produce exhaust gases containing:

• nitrogen

• water vapor

• oxygen

• carbon dioxide

Separating CO₂ from this mixture is difficult and energy intensive, but MOFs offer a solution.

Their pores can be engineered to reversibly adsorb to CO₂ while letting other gases pass through, making it suitable for CO₂ capture from the atmosphere and flue gas. 

“Because the ideal material for carbon dioxide capture from flue and combustion gases requires high selectivity in the presence of water, it is useful to target MOFs in which the competition between carbon dioxide and water for adsorption is minimized. In this respect, chemical binding of carbon dioxide in a recent MOF to make organic carbonates reversibly is a promising approach” [1].

Compared with conventional liquid amine systems, future MOFs could potentially reduce the energy required for carbon capture while lowering operating costs.

Although commercial deployment remains limited, MOFs continue to be among the most heavily researched carbon capture materials today.

Hydrogen Storage

Hydrogen is considered an important future clean fuel. However, storing enough hydrogen safely inside vehicles remains challenging.

Compressed hydrogen tanks require extremely high pressures while liquid hydrogen requires extremely low temperatures.

MOFs provide another possibility. In 2003, MOF-5 confirmed the potential of MOFs for hydrogen adsorption. “In general, the functionality of organic linkers has little influence on hydrogen adsorption (86), whereas increasing the pore volume and surface area of MOFs markedly enhances the gravimetric hydrogen uptake.” [1].

“NU-100 and MOF-210 exhibit hydrogen adsorption as high as 7.9 to 9.0 weight percent (wt%) at 56 bar for both MOFs and 15 wt% at 80 bar for MOF-210” [1].

Hydrogen molecules adsorb onto the enormous internal surface area inside the framework. However, increasing the surface area is not always effective for increasing volumetric hydrogen adsorption. Open metal sites can enhance hydrogen uptake capacity. 

If researchers continue improving storage capacity under practical temperatures and pressures, MOFs could become an important component of future hydrogen-powered transportation. “Mercedes-Benz has already deployed MOF hydrogen fuel tanks in a fuel cell–powered demonstration model, the F125” [1].

Catalysis

Many industrial chemical reactions require catalysts. Traditional catalysts often contain expensive precious metals and may only work under specific conditions.

“The high surface areas, tunable pore metrics, and high density of active sites within the very open structures of MOFs offer many advantages to their use in catalysis” [1].

MOFs can support homogenous catalysts, stabilize catalysts with short lifespans, perform size selectivity, and encapsulate catalysts with their pores. For example, removal of solvent from HKUST-1 exposes open metal sites that may act as Lewis acid catalysts as shown in 2006. MOFs can also be used as a heterogeneous catalyst, including PIZA-3.

Chemical Separations

Separating chemicals often consumes enormous amounts of industrial energy.

Many separations rely on repeated heating and cooling through distillation. However, MOFs provide an alternative. 

Instead of boiling mixtures apart, they separate molecules according to:

• size

• polarity

• shape

• chemical interactions

They can separate hydrocarbons, toxic molecules (ammonia, chlorine, etc.) and water. 

“For instance, Cu2(PZDC)2(Pyz) (PZDC = pyrazine-2,3-dicarboxylate; Pyz = pyrazine) selectively takes up acetylene over carbon dioxide through hydrogen bonding between acetylene and oxygen atoms on the MOF internal surface” [1].

Although ammonia used to be considered too reactive for MOFs, Zr-MOFs, such as UiO-66-NH2 [Zr6O4(OH)4(BDC-NH2)6] and other derivatives, maintain their structures with adsorbing and desorbing ammonia. 

Fuel Cells 

MOFs are also promising materials for proton-conducting membranes in fuel cells, offering a potential alternative to conventional polymer electrolytes such as Nafion. 

Fuel cell membranes must efficiently transport protons while maintaining chemical stability, but traditional polymers face limitations including high cost, dependence on humidity, and reduced performance at elevated temperatures. Because MOFs possess highly tunable pore structures, customizable chemical functionalities, and strong thermal and chemical stability, they provide a unique platform for designing next-generation proton-conducting materials.

Early studies showed that MOFs could transport protons, although initial conductivity values were relatively low. Researchers later discovered that improving proton conductivity required introducing acidic functional groups, such as carboxylic, phosphonic, or sulfonic acids, into the framework. These groups promote proton transfer by creating hydrogen-bond networks and providing additional proton sources within the pores. This approach was demonstrated in materials such as functionalized MIL-53, where adding acidic groups significantly improved proton transport. 

Researchers have also improved conductivity by incorporating mobile proton carriers directly into MOF pores. Molecules such as 1H-1,2,4-triazole, imidazole, and histamine can act as proton transport agents, forming networks that allow protons to move more rapidly through the material. These studies revealed that placing highly mobile proton carriers inside MOF pores can greatly enhance conductivity compared with frameworks that rely only on their intrinsic chemical structure.

Despite these advances, several challenges remain before MOFs can replace conventional fuel cell membranes. Practical fuel cell operation requires materials that maintain high conductivity at 120–180°C and under low-humidity or anhydrous conditions, where proton movement becomes more difficult. However, the ability to precisely control pore size, chemical functionality, and stability makes MOFs attractive candidates for future fuel cell technologies. By overcoming current limitations, MOF-based proton conductors could enable more efficient, durable, and cost-effective fuel cells for clean energy applications.

Challenges of MOF Scale-Up

Despite their enormous promise, MOFs are not yet widespread commercial materials.

Several challenges remain.

Cost

Many MOFs require expensive precursors or complex synthesis methods.

Reducing manufacturing costs remains essential for large-scale deployment.

Stability

Some early MOFs degraded when exposed to:

• moisture

• oxygen

• acids

• elevated temperatures

Researchers have since developed much more robust frameworks, but stability remains an important design consideration.

Manufacturing at Scale

Producing a few grams of MOF in a laboratory is very different from manufacturing thousands of tons for industrial use.

Large-scale production requires:

• consistent crystal quality

• low-cost synthesis

• efficient purification

• reproducible performance

• sustainable manufacturing methods

Scaling remains one of the biggest engineering challenges.

Why This Matters

The Chemistry and Applications of Metal–Organic Frameworks helped establish MOFs as a major research field by demonstrating that these materials were not simply scientific curiosities—they were versatile platforms capable of addressing some of society's largest technological challenges.

Since its publication:

• thousands of new MOFs have been synthesized

• carbon capture research has accelerated dramatically

• water-harvesting devices have been demonstrated

• biomedical applications have expanded rapidly

• machine learning is now being used to design new MOFs

• researchers are exploring electrically conductive MOFs for batteries and electronics

Today, MOFs are investigated for applications ranging from sustainable energy to environmental remediation and advanced healthcare.

Many of the world's biggest sustainability challenges involve controlling molecules:

• capturing carbon dioxide

• producing clean hydrogen

• storing renewable energy

• purifying water

• reducing industrial energy use

• recycling valuable chemicals

MOFs provide an entirely new toolkit for solving these problems because scientists can tailor their structures at the molecular level rather than relying on naturally occurring materials.

Although widespread commercialization still faces obstacles, the field continues to advance rapidly. The vision presented in this landmark paper—that programmable porous materials could transform energy, environmental, and industrial technologies—has guided more than a decade of innovation and remains highly relevant today.

References

1. Furukawa, H., Cordova, K. E., O’Keeffe, M., & Yaghi, O. M. (2013). The chemistry and applications of metal-organic frameworks. Science (New York, N.Y.), 341(6149), 1230444. https://doi.org/10.1126/science.1230444

2. Raptopoulou, C. P. (2021). Metal-Organic Frameworks: Synthetic Methods and Potential Applications. Materials, 14(2), 310. https://doi.org/10.3390/ma14020310

3. Meet Metal-Organic Frameworks, Chemistry’s New Miracle Materials | College of Chemistry. (2018). Berkeley.Edu. https://chemistry.berkeley.edu/news/meet-metal-organic-frameworks-chemistry%E2%80%99s-new-miracle-materials

4. Metal-Organic Frameworks (MOFs) - Amrita Vishwa Vidyapeetham. (2023). In www.amrita.edu. https://www.amrita.edu/news/metal-organic-frameworks-mofs/

5. Metal–organic frameworks for the future. Nat. Nanotechnol. 20, 1539 (2025). https://doi.org/10.1038/s41565-025-02095-9

6. SvanteAdmin. (2021). MOF Sorbent on a Roll – A Scalable Solution for Gigaton Scale Carbon Capture. In Svante. https://www.svanteinc.com/press-releases/a-scalable-solution-for-carbon-capture/

7. Rosi, N. L. (2003). Hydrogen Storage in Microporous Metal-Organic Frameworks. Science, 300(5622), 1127–1129. https://doi.org/10.1126/science.1083440

8. Li, D., Xu, H.-Q., Jiao, L., & Jiang, H.-L. (2019). Metal-organic frameworks for catalysis: State of the art, challenges, and opportunities. EnergyChem, 1(1), 100005. https://doi.org/10.1016/j.enchem.2019.100005