F. STODDART, O. YAGHI and S. TAHA, H2MOF, Irvine California

Renewables are a growing component of the global energy mix. Electrification continues to make inroads in the personal and light vehicle sectors; however, key sectors, such as heavy road transport, industry, aviation and shipping, remain stubbornly resistant to decarbonization. This is where Power-to-X (PtX) plays a vital role. PtX refers to turning electricity into something else. For example, clean energy from renewables can be used to extract hydrogen (H₂) from water by electrolysis. The resulting green (renewable) H₂ can be used on its own as a fuel or combined with other chemicals to produce eAmmonia and eMethanol.

However, to be truly feasible, we must first overcome a major bottleneck: current methods of storing H₂ are expensive, difficult and inefficient. Metal–organic frameworks (MOFs) are a type of nanomaterial with a unique structure that allows them to exhibit exceptionally high surface areas. MOFs are the result of breakthroughs in reticular chemistry, and small amounts can safely and cost-effectively store—and release on demand—large amounts of H₂.

The founder of reticular chemistry and the founder of artificial molecular machinery have joined forces to overcome the challenge hindering the wider adoption of H₂ as a viable clean fuel, ultimately helping to tackle global warming and climate change. Nobel laureate Professor Sir Fraser Stoddart, the winner of the Nobel Prize in Chemistry in 2016 for the design and synthesis of artificial molecular machines and Professor Omar Yaghi, founder of Reticular Chemistry and winner of the Albert Einstein Award of Science in 2017, have joined forces to found, H2MOF, a U.S.-based company with the mission to design and develop durable and efficient solid-state H₂ storage solutions that work under ambient temperature and low pressure. 

Despite an increasing penetration of renewables into the energy system in recent years, the energy system of today is still vastly fossil based, thus contributing to the ongoing climate crisis. H2MOF considers the wider adoption of H₂ as a crucial steppingstone towards a truly sustainable and decarbonized energy system. 

Today, storing H₂ often involves compressing or liquefying it by cooling it down. These conversions use a significant amount of energy and, therefore, are inefficient and expensive. H2MOF takes a different approach, capitalizing on decades of discoveries and advancement in reticular chemistry and artificial molecular machinery to develop novel materials designed with atomic precision to tackle the challenging properties of H₂ molecules. 

Reticular chemistry is the science of linking molecular building blocks by strong chemical bonds. In recent years, advances in reticular chemistry have led to the identification of thousands of MOFs, covalent organic frameworks (COFs) and H₂-bonded organic frameworks (HOFs), which are nanomaterials composed of repeating arrays of these cage-like building blocks.

Due to their large surface area and porosity, MOFs are ideal for H₂ storage. MOFs have a lattice framework made up of metal ions or clusters coordinated with organic ligands. There are microscopic unfilled areas within this structure known as ‘voids’ or ‘pores,’ which allow H₂ gas molecules to enter and cling to the MOFs’ surface. The H₂ gas is then adsorbed onto the voids’ surfaces. Weak intermolecular forces, such as those known as ‘van der Waals interactions,’ promote this adsorption. When needed, the MOFs can be decompressed, releasing the stored H₂ from the voids. This can be managed and monitored depending on its particular application.

Current MOFs used for H₂ storage typically require extreme low temperatures to achieve efficient storage density. H2MOF deploys the latest advancements and discoveries in the field of reticular chemistry and artificial molecular chemistry to design exotic novel materials that can achieve efficient H₂ storage density at ambient temperature and low pressure.

Researchers have synthesized MOFs that feature a surface area of more than 7,800 square meters per gram. To put this into context, if you could lay out the available surface area in a teaspoon of this material (around a gram of solid), it would cover an entire soccer field.¹ Furthermore, the benefits of using MOFs include:

• Low-pressure storage: A MOF-based system enables high energy storage density at pressures as low as 20 bar, significantly lower than the 700-bar pressure used in commonly used high-pressure H₂ cylinders, giving significant energy savings.
• Long-term storage: H2MOF’s H₂ storage technology is characterized by low pressure and ambient temperature, features that in turn enable long-term storage. None of the H₂ is lost through evaporation, as happens with energy-intensive liquefaction.
• Ambient-temperature storage: This enables safe storage at ambient temperature; there is no need for the energy needed to achieve the –253°C required to liquefy the H₂ and to maintain it at this extreme temperature. Again, the energy savings are significant.
• Safer storage conditions: High pressures mean high costs and high safety risks. Complex and costly safety protocols must be followed when handling highly pressurized H₂.

According to Sir Fraser Stoddart, co-founder of H2MOF, “H₂ fuel has the highest energy density among all combustible fuels; simultaneously, it has zero emissions. These reasons are amongst the key drivers toward considering H₂ energy as the best choice for a sustainable and clean future for humankind.” 

According to Professor Omar Yaghi, co-founder of H2MOF, “H₂ is the most abundant element in the universe. It’s the lightest element, and therefore it is very challenging to store and transport in an efficient and safe way. Over the past two decades, I have been working on improving the efficiency of H₂ storage materials based on reticular chemistry, and we have made a lot of progress.”

The global demand for H₂ is expected to increase significantly in the years to come. The European Union (EU) has set ambitious goals, that include the production of 10 MMt of green H₂ in the EU by 2030. The U.S. is also investing in H₂’s potential to decarbonize the economy. The U.S. Infrastructure Investment and Jobs Act allocates $8 B in grants to regional H₂ projects. The U.S. Inflation Reduction Act establishes a tax credit of up to $3/kg of H₂ for production with the lowest associated emissions. 

Reticular chemistry, and specifically MOF technology, has received wide interest and recognition worldwide as a promising technology for solving the H₂ storage challenge. The U.S. Department of Energy listed MOF technology as a leading technology candidate to solve the H₂ storage challenge. There are also several research programs that include consortiums from multiple reputable research institutions from multiple European countries, funded by the EU, that focus on MOF technology to develop more efficient H₂ storage solutions.

Dr. Samer Taha, CEO of H2MOF said, “Our technology aims at significantly cutting the energy penalty associated with storing H₂ using high-pressure tanks or associated with liquefying H₂. Our technology roadmap targets the development of H₂ storage solutions that can achieve high storage density at ambient temperature and at pressures as low as 20 bar, which is less than 3% of the pressure of some of the high-pressure 700-bar H₂ storage tanks used in the industry today. Our technology relies on our novel material that attracts H₂ molecules towards the nano-scale cavities of the material. This bonding then retains the H₂ molecules inside the novel material while also allowing for their efficient release when required.”

H2MOF is currently working on the optimization and scaling of the novel material and on the integration of its H₂ storage solution. Ultimately, the product offerings will be targeting several application areas including long-term storage of H₂, storage of H₂ during long-distance transportation, and - when used as a fuel for transportation - solutions for various means of transportation such as light-duty vehicles, heavy duty trucks, trains, ships and airplanes.

About the authors

SIR FRASER STODDART is one of the most influential scientists in the world today in the field of supramolecular chemistry. He is the founder of the artificial molecular machinery field of science and the one who discovered the mechanical bond in the field of supramolecular chemistry. Stoddart has received more than 73 global awards and medals from world leaders and leading scientific organizations for his discoveries and outstanding scientific contributions. Among the top awards are the Nobel Prize in Chemistry in 2016, the Knighthood by Her Majesty the late Queen Elizabeth in 2007 and the Albert Einstein World Award of Science in 2007.

OMAR YAGHI is one of the top inventors and among the most-cited chemists in the world today. Professor Yaghi is the founder of the reticular chemistry field of science. Among his top inventions are the MOFs, zeolitic imidazolate frameworks (ZIFs), COFs and the molecular weaving technologies. Yaghi has received more than 55 prestigious global awards and medals throughout his celebrated career, including the Albert Einstein World Award of Science in 2017, the Wolf Price in Chemistry in 2018, the Gregori Aminoff Prize in 2019, and the Ernest Solvay Prize in 2024.

SAMER TAHA has more than 20 yr of experience in R&D, technology commercialization and entrepreneurship in ICT and Nanotechnology. He started his work as an R&D scientist at Intel technology group in Oregon, where he worked for 5 yr. Then, between 2007 and 2017, he founded and led the expansion of two startups in the fields of ICT and managed the delivery of more than $200 MM of ICT projects. He was later appointed as the Executive Chairman of Revonence, a value-add private equity holding group, where he shifted the focus of the group toward nanotechnology commercialization. Between the years 2018 and 2020, Dr. Taha worked closely with Nobel Laureate, Professor Fraser Stoddart, and his team of scientists, on the scaling and commercialization of the cyclodextrin-based metal-organic frameworks (CD-MOFs) technology, the only edible and biodegradable MOF known to date. He also led the development of a manufacturing facility, the first of its kind in the world, based in Irvine, California, for the large-scale synthesis, activation and integration of the organic nanotechnology CD-MOF.

LITERATURE CITED

¹ nano werk, “What is a MOF (metal organic framework)?” online: https://www.nanowerk.com/mof-metal-organic-framework.php