Hydrogen is an important but volatile chemical, with safe storage and transport remaining a significant challenge.
New research from the University of Chicago’s CD4DC Energy Frontier Research Center offers a promising solution.
In a paper recently published in Nature Chemistry, the CD4DC Center—which brings together researchers from UChicago Pritzker School of Molecular Engineering (UChicago PME), the UChicago Chemistry Department, Northwestern University, Stony Brook University and other institutions—explore Liquid Organic Hydrogen Carriers (LOHCs) as a way to handle hydrogen in a more safe and efficient manner.
“This research points toward a future where hydrogen could be stored and delivered in a familiar, liquid form–without the need for complex tanks or high pressures,” said co-author Mukunda Mandal, who was a University of Chicago postdoctoral researcher at the time of the research.
LOHCs absorb and release hydrogen through reversible chemical reactions and remain liquid under ambient conditions. Unlike other carriers such as ammonia or metal hydrides, LOHCs are non-toxic, non-volatile, and compatible with existing fuel infrastructure, making them particularly well-suited for vehicles and other mobile applications.
The researchers developed a new catalyst design strategy to support more practical LOHC systems. said CD4DC Director Laura Gagliardi, who is also the Richard and Kathy Leventhal Professor in the University of Chicago Department of Chemistry, the UChicago Pritzker School of Molecular Engineering, and the James Franck Institute.
They describe an approach using metal-organic frameworks (MOFs), porous, crystalline materials with exceptionally high internal surface areas, as scaffolds to host metal–sulfur catalytic sites, which show promise for activating hydrogen.
The team focused on modifying two MOF platforms that contain triazole–a biologically active organic molecule commonly found in enzymes. Starting with chlorine-bound versions of these materials, they developed a step-by-step method to replace the chlorine atoms first with oxygen-based groups and then with sulfur-based groups. This strategy preserved the MOFs’ crystalline structure while creating active sites that exhibited high hydrogenation activity.
Diving deeper into how and why these materials work so well, the team discovered that the metal-sulfur bond’s changeable, unstable characteristics – its “lability” – plays a critical role in generating “open metal sites.” These are vacant spaces around a metal atom where a small molecule or ion can bond. These open metal sites help the hydrogen perform better while promoting adsorption – sticking to the surface of materials rather than being absorbed by them. These findings could help guide the design of even more effective catalysts in the future.
Citation: “Introducing metal–sulfur active sites in metal–organic frameworks via post-synthetic modification for hydrogenation catalysis,” Xie et al, Nature Chemistry, July 24, 2025. DOI: 10.1038/s41557-025-01876-y