Tang Prize winner Omar Yaghi hails chemistry as a climate solution

Taipei, Sept. 28 (CNA) Climate problems can be addressed with reticular chemistry, 2024 Tang Prize in Sustainable Development awardee Omar M. Yaghi proclaimed in his laureate lecture in Taipei on Saturday as he described the new field of chemistry he has pioneered.

In his talk on "Ultra-porous crystals for a sustainable future," Yaghi, the James and Neeltje Tretter Chair Professor of Chemistry at the University of California, Berkeley, highlighted how his groundbreaking findings could help fight climate change and improve access to clean drinking water.

Defining reticular chemistry as "the chemistry of linking molecular building blocks by strong bonds to make crystalline, extended structures," Yaghi said these ultra-porous crystalline materials can capture and control small molecules, such as carbon dioxide and water, in the atmosphere.

The porosity of these new materials, which he called metal organic frameworks (MOFs) and covalent organic frameworks (COFs), result in surface areas equal to about a football field per gram of material, Yaghi said, ideal for extracting carbon dioxide or water from the air.

"You can tailor the pores so that the environment inside the pores can be tailored toward a specific application, so we have an infinite frontier, almost an infinite number of structures and hundreds of applications" that can be invented for sustainability, he said.

Yaghi's pores attract carbon and water by having them adhere to their surface, which is why their surface area is important.

He cited some of the applications of MOFs and COFs in capturing CO2 from flue gases and harvesting water from the air.

Capturing carbon dioxide from point sources, or in this case trapping CO2 in the flue gas from cement plants, before it reaches the atmosphere, has already been commercialized in Canada, he said.

Yaghi and his team have also found a way to use COFs to solve the material stability problem in capturing CO2 directly from the air, which according to Yaghi has been "a long-standing challenge" for existing direct air capture (DAC) technologies.

"What remains is to scale up this COF, which shouldn't be impossible because COFs are made from very similar components to polymers. They're all organic and organic chemists never fail to scale up a material that they want," he said.

Once the quantity is scaled up, "you don't even need to design the device that this material would go into as these devices already exist; they use inferior materials, so all you do is replace those materials with these new materials," Yaghi said.

At the press conference following his speech, Yaghi was asked about the prospects for the commercialization and widespread use of his materials.

He said he believed that the scale-up of COFs would take little time and that the "outlook [for commercialization] is very good" because COFs can be dropped into existing devices."

Regarding water harvesting, Yaghi said he and his team developed an MOF that is "ideal for taking water out of the air."

The MOF was used in a hand-held device designed by Yaghi's students that had no power input other than the ambient sunlight, and when it was tested in Death Valley, California, the driest desert in North America, it was able to harvest pure water, he said.

Bigger, electrified devices can be designed to make more water, he said, citing an example of using 200 grams of MOF to produce five liters of water per day.

"This device is no larger than a small microwave oven, and it could fit in your kitchen with the other appliances with your coffee maker," Yaghi said.

"It gives you five liters of water every day for at least six, seven years without having to replace the MOF," and it uses very little electricity, Yaghi said.

When scaled up, it means that "if you have one ton of MOF with no energy input, you're going to deliver 3,000 liters of water per day, every day, for seven years without having to replenish, replace or maintain the MOF at one cent per liter."

"And if you have one ton of MOF in an electrified system, it's going to deliver 60,000 liters of water per day at less than two cents per liter," Yaghi said.

He said the technology will give "water independence, which is a basic human right," to each of us in the world.

The improved rate of water capture per unit of MOF of the scaled-up version over the prototype could come from a more efficient MOF by manipulating its materials, Yaghi suggested.

Yaghi also talked about the revolution brought by AI in his field, which has lowered the entry threshold for discovering new materials in reticular chemistry.

"AI will help us speed up discoveries and help us scale discoveries, meaning that more than just a few labs in a few countries will be able to solve the world's problems," he added.

(By Alison Hsiao)

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