The clean energy transition requires new means to transport energy that are less reliant on burning fossil fuels. This requires new materials to catalyze reactions to store and extract energy from chemical energy carriers without combustion.
One promising set of materials to create these catalysts is metal-organic frameworks (MOFs), molecular structures made of metal ions and organic linkers.
Scientists and engineers at the University of Chicago Pritzker School of Molecular Engineering (UChicago PME) and the Department of Chemistry have developed a new computational tool that predicts which MOFs will be most stable for a given need.
Created by PhD student Jianming Mao and Prof. Andrew Ferguson , the tool predicted a new iron-sulfur MOF that was then synthesized by postdoctoral researcher Ningxin Jiang and Prof. John Anderson , and characterized by scientists at Stony Brook University.
The work, conducted at UChicago's Catalyst Design for Decarbonization Center , an Energy Frontier Research Center funded by the U.S. Department of Energy led by Prof. Laura Gagliardi, could help aid in the decarbonization energy transition. The results were published in the Journal of the American Chemical Society .
"Making new catalyst materials that can help decarbonize the economy is a big priority for this center, and we showed that it's possible through an interdisciplinary science environment that brings together computational and experimental scientists and engineers," Ferguson said.
Creating thermodynamically stable materials
Because they are porous and highly tunable, MOFs stand out as good candidates for catalysis, energy storage, and as sensors. But designing and synthesizing MOFs is not easy. More than 500,000 MOFs have been predicted by computational tools, but only a fraction of those have been successfully synthesized.
"Some MOFs are more stable than others, and even if you figure out which design is good, it might not work when you try to create it in the lab," Mao said.
To change this, Ferguson and his team created a computational screening pipeline that can attach stability predictions to candidate MOF designs. The calculations are conducted using a technique known as thermodynamic integration, where the researchers converted the MOF into a simpler system with a known thermodynamic stability on the computer. By measuring the work done along this pathway, it is possible to calculate the stability of the original MOF.
"This technique is commonly known as 'computational alchemy' because it performs a chemical transmutation of one chemical system into another, similar to how the ancient alchemists sought to convert lead into gold," Ferguson said. "It sounds fantastical, but the method is based in sound mathematical and statistical mechanical theory and is a cornerstone of computational chemistry that is prevalently used in computational drug design."
While these materials are governed by quantum mechanics, conducting quantum-mechanical calculations for each potential compound is extremely computationally expensive and not feasible. Doing so would require centuries of computing time.
So the team used classical physics approximations of the quantum mechanics of how the atoms would interact. That cut the computing time down to one day.
"It wasn't clear if the classical mechanical approximations were going to be accurate enough to do the job," Ferguson said. "It was a bit of a gamble for us. Fortunately, it worked out, and they were accurate enough." To ensure their approach worked, the team showed the screening pipeline could retrospectively predict MOFs that had been previously reported and were in agreement with quantum mechanical calculations on a small number of systems conducted by Andrea Darù, a postdoctoral researcher in the lab of Prof. Laura Gagliardi.
The calculations were supported by UChicago's Research Computing Center .
Tool could be used to predict other new materials
The screening pipeline then ultimately predicted a new iron-sulfur MOF, known as Fe4S4-BDT—TPP, that would be stable and synthesizable.
The MOF was synthesized in Anderson's lab, then characterized through powder X-ray diffraction by Karena Chapman and her team at Stony Brook University and Brookhaven National Laboratory and Alex Filatov, director of X-ray Research Facilities at UChicago. It proved to be thermodynamically stable and possess the structure predicted by the computational models.
"This model is a step in the right direction of being able to predict materials rather than try to synthesize them and figure out what they are," Anderson said. "It accelerates the discovery process very rapidly."
Next, the team will continue to synthesize this new MOF and study it to see just how well it performs as a catalyst.
In the meantime, Ferguson and Mao have made their virtual screening pipeline publicly available to help other research teams discover stable MOFs. "This tool will allow scientists to screen a large number of chemical compounds to find the right one for their need," he said.
Other authors on the paper include Jianming Mao, Ningxin Jiang, Alexander S. Filatov, Jessica E. Burch, Jan Hofmann, Simon M. Vornholt, and Karena W. Chapman.
CITATION: "Structure and Synthesizability of Iron-Sulfur Metal-Organic Frameworks," Mao et al, Journal of the American Chemical Society. May 16, 2025 DOI: https://doi.org/10.1021/jacs.4c16341
FUNDING: Department of Energy
