KAIST develops AI-powered material design technology to boost carbon capture, hydrogen storage

South Korean researchers have developed a custom material design technology that more selectively captures carbon dioxide and stores hydrogen more efficiently.

KAIST announced Tuesday that a research team led by Kim Ji-han, a professor in the Department of Chemical and Biomolecular Engineering, has developed a technology that arranges gas molecules in orderly, crystal-like formations inside porous materials and uses AI to design new materials capable of producing any desired gas arrangement.

The team used metal-organic frameworks, or MOFs, which can trap or filter gas molecules in their microscopic pores. Like a sponge absorbing water, MOFs hold gas within their tiny cavities — earning them the description of "molecular sponges." By surveying a vast number of MOF structures, the researchers identified a phenomenon they call a "gas lattice," in which gas molecules arrange themselves in a regular, crystal-like order rather than scattering randomly. They then used AI to design new porous structures capable of producing a desired gas arrangement.

The team verified the phenomenon using xenon, a single-element noble gas. After searching through an extensive library of MOF structures, they found that xenon forms a regular lattice inside a specific cobalt-based porous material known as Co-CAU-36.

Computer simulations showed that instead of scattering randomly within the pores, xenon atoms aligned in a fixed crystalline pattern called a body-centered cubic, or BCC, lattice. Rather than balls tumbling loosely into a box, the xenon atoms settled into designated positions — as if each had been placed precisely in its assigned spot.

This occurred because the MOF's microscopic pores acted as a kind of mold, guiding the xenon atoms into specific positions. Unlike conventional crystallization, which requires extreme conditions applied directly to the gas itself, this approach uses the geometry of the space the gas occupies to produce an orderly arrangement.

Particularly striking results emerged when different gases were mixed. When xenon and krypton — two gases with high industrial separation value — were introduced simultaneously, xenon first formed a regular shell-shaped lattice while krypton settled into the center. Rather than mixing, the two gases occupied distinct, separate spaces within the material.

The researchers expect the technology to eventually be extended to a range of gases including carbon dioxide and hydrogen, enabling the design of materials that can selectively capture, separate or efficiently store specific gases depending on the application.

"The key finding of this research is that gas inside a MOF does not simply adsorb — it can form a structurally defined ordered state we call a framework-induced gas lattice," Kim said. "This opens up potential applications in gas storage, selective adsorption and separation, responsive materials and membrane separation."

The findings were published in Nature Communications on June 23.