Researchers at Fudan University and collaborating Chinese institutes have developed a novel, low-cost catalytic cycle that promises to revolutionize the separation, storage, and transportation of hydrogen. Published in Nature Energy, their method utilizes a reversible chemical reaction between gamma-butyrolactone (GBL) and 1,4-butanediol (BDO) as liquid organic hydrogen carriers (LOHCs), driven by an impurity-tolerant inverse Al2O3/Cu catalyst. This breakthrough addresses critical challenges in the hydrogen economy, particularly the high costs and complexities associated with purifying and distributing industrial crude hydrogen.

Industrial hydrogen, often a byproduct of chemical processes, typically contains significant impurities such as carbon monoxide (CO), carbon dioxide (CO₂), nitrogen (N₂), and light hydrocarbons. Conventional purification methods like pressure swing adsorption (PSA) and membranes are energy-intensive and prohibitively expensive for these impure streams. "One of our key inspirations was a pressing industrial challenge in China, where highly developed process industries generate vast amounts of crude and byproduct hydrogen," stated Professor Yifeng Zhu, senior author of the paper. He emphasized that much of this hydrogen-rich gas is currently flared or vented due to the lack of cost-effective recovery technologies, hindering the broader deployment of clean hydrogen.

The proposed strategy involves the hydrogenation of GBL to BDO at 170°C, effectively capturing hydrogen from impure industrial gas streams. This process achieves over 99.2% H2-to-BDO selectivity, notably suppressing side reactions even with gas feeds containing over 50 vol.% CO and CO₂—a significant hurdle for state-of-the-art catalysts which typically deactivate at much lower impurity levels. The resulting hydrogen-rich BDO, a cheap and safe oil-like liquid, can then be safely stored and transported using existing liquid fuel infrastructure, including tanks, pipelines, and trucks.

Upon demand at the destination, catalytic dehydrogenation regenerates GBL and releases high-purity hydrogen, achieving greater than 99.998% purity, entirely free of COx impurities. "A key advantage of our strategy is that both the catalyst and the liquid organic hydrogen carriers (GBL/BDO) are abundant and inexpensive," explained Prof. Zhu. He further highlighted that the single-step hydrogen capture and storage, coupled with the system's compatibility with ambient conditions and existing fuel infrastructure, makes the approach highly scalable and safe. This robust impurity tolerance is a major leap forward, overcoming a critical limitation of previous catalytic systems.

This innovative, low-cost catalytic cycle offers a practical and scalable pathway to upgrade waste and crude hydrogen resources into valuable, high-purity hydrogen. By bypassing expensive purification steps and leveraging existing infrastructure, the technology is poised to significantly boost global hydrogen utilization in the near term, contributing substantially to decarbonization efforts across various industrial and energy sectors.