USA

Omar M. Yaghi

2024 Balzan Prize for Nanoporous Materials for Environmental Applications

For groundbreaking contributions to the discovery and development of nanoporous framework materials, and advancing their applications in carbon capture, hydrogen storage, and water harvesting from desert air. Yaghi developed foundational design principles and innovative synthetic methods, creating two extensive classes of nanoporous materials: metal-organic frameworks (MOFs) and covalent organic frameworks (COFs). These pioneering materials are now at the forefront of global efforts to tackle critical sustainability and environmental challenges facing our planet.

Omar Yaghi founded reticular chemistry, the science of constructing chemical structures from molecular building blocks. He is renowned for pioneering metal-organic frameworks (MOFs), covalent organic frameworks (COFs), and zeolitic imidazolate frameworks (ZIFs), materials celebrated for their extraordinarily high surface areas and nanoporosity. The porosity of these frameworks far exceeds that of traditional porous materials. This ultrahigh porosity significantly enhances their utility in clean energy storage and generation, including the storage and separation of hydrogen, methane, and carbon dioxide, as well as in clean water production, supercapacitors, and conductive systems. The building-block approach he developed has sparked exponential growth in the creation of new materials with unprecedented chemical diversity and complexity, as evidenced by the extensive body of literature on MOFs.

In the early 1990s, Omar Yaghi proposed using molecular building blocks and strong bonds to create crystalline materials. At the time, the scientific community deemed this concept chemically impossible because strong bonding between such molecular building blocks typically resulted in ill-defined, amorphous solids. This perception changed in 1995 when he successfully demonstrated, for the first time, that metal ions could be connected by negatively charged organic linkers to form strong bonds and create ordered crystalline framework materials. This groundbreaking finding, published in Nature, enabled the development of a new class of materials: MOFs.

Recognizing the potential of MOFs in harnessing the power of gases and molecules like hydrogen, carbon dioxide, and water, he understood the necessity of proving their architectural stability. In 1998, he reported the measurement of the first gas adsorption isotherms on a MOF made from copper oxide clusters and terephthalate, demonstrating the permanent porosity of the MOF. This led to a highly cited Nature publication in 1999, where he described the now-iconic MOF-5. MOF-5 showcased ultrahigh porosity, with a surface area of approximately 3,000 square meters per gram, and high architectural stability. The record-breaking porosity and robustness of MOF-5 established the field of MOFs and marked the beginning of Omar Yaghi’s pioneering work in using MOFs’ porosity for hydrogen storage, carbon capture, and water harvesting from air.

MOFs became the materials of choice for these applications due to their nano-sized pores, a property crucial for achieving clean air, clean energy, and clean water. Professor Yaghi also developed a strategy for creating MOFs with surface areas of up to 7,000 square meters per gram, further realizing the immense potential of these materials.

Following these achievements, he discovered and developed another extensive class of materials, described in a 2005 Science publication: COFs. COFs are composed entirely of organic molecules held together by covalent bonds, the strongest bonds in chemistry. This makes COFs highly durable and, due to their light element constituents, the least dense porous materials. He developed COFs with specific nanopore sizes and environments to compact hydrogen and carbon dioxide, and to trap water from desert air, all under practical conditions.

His strong-bond approach and the precision of his chemistry confer high thermal and chemical stability to these materials, enabling them to be used and cycled for many years. The ultrahigh porosity of his frameworks allows for economical use in clean energy gas storage, with the added advantages of high capacity and efficiency. Omar Yaghi’s groundbreaking discoveries have provided crucial tools to address the climate crisis.