【Frontiers in HaiChuan Chemical Technology】New breakthroughs achieved in propane dehydrogenation research in China

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On February 6, the School of Chemical Engineering at Tianjin University reported that recently, the top international journal in the field of chemistry, the Journal of the American Chemical Society, published an article on its cover highlighting an important breakthrough achieved by a Chinese research team in the field of propane dehydrogenation catalysts. 　　A team led by Professor Liu Guozhu from the School of Chemical Engineering at Tianjin University, in collaboration with research teams from Taiyuan University of Technology and Nankai University, has successfully developed an iridium single-atom catalyst encapsulated in germanium-substituted zeolite (IrGe@S-1), achieving for the first time in the world the ultra-long-term stable operation of iridium single atoms in propane dehydrogenation reactions. Through a design approach that combines rigidity and flexibility, this study offers a new pathway to overcoming the global challenge of the easy deactivation of propane dehydrogenation catalysts at high temperatures. 　　Propylene is a key basic raw material in modern chemical industry and is regarded as the “cornerstone” of the petrochemical industry. The global market for propylene produced through the propane dehydrogenation process is worth hundreds of billions of dollars, and it has become one of the fastest-growing routes for propylene production. 　　In the massive industrial \"heart\" of propane dehydrogenation units, the catalyst is its most crucial \"valve.\" Currently, the traditional platinum (Pt)-based and chromium (Cr)-based catalysts commonly used in global propane dehydrogenation plants face two major challenges in reaction furnaces operating at temperatures of 550–650°C: carbon deposition on the active sites and sintering/agglomeration, which gradually leads to a loss of their catalytic activity. The performance of the catalyst directly determines how long the device can operate continuously and stably, and it is a key factor affecting the production efficiency and economic benefits of the entire system. 　　Currently, scholars around the world are conducting research simultaneously through various approaches, including improving metal efficiency, developing alternative metals, exploring new reaction pathways, and enhancing catalyst stability. Among them, single-atom catalysts have attracted considerable attention because they can significantly reduce \"carbon deposition coverage\" and push the utilization efficiency of precious metal atoms to the theoretical limit. However, single-atom catalysts are prone to \"sintering and agglomeration\", that is, they tend to migrate and aggregate under high-temperature reaction conditions, resulting in deactivation; only by maintaining their long-term stability can single-atom catalysts achieve their maximum effectiveness. 　　To address this challenge, the team led by Professor Liu Guozhu from the School of Chemical Engineering at Tianjin University adopted a strategy that combined rigidity and flexibility, enabling iridium single atoms to maintain ultra-long stability of over 800 hours in propane dehydrogenation reactions. These atoms exhibited high activity, excellent selectivity, and resistance to carbon deposition, providing an original solution to overcome the aforementioned difficulties. 　　The research team creatively incorporated germanium atoms into the pure silicon zeolite framework. The introduction of germanium acts like stronger \"anchors\" built within the zeolite framework; it forms very strong chemical bonds with iridium atoms, firmly \"locking\" them in specific positions so that they cannot move or aggregate even at high temperatures, thereby achieving a \"rigid\" anchoring effect. 　　Studies have found that during the reaction process, the introduced propane molecules interact dynamically with the catalyst, \"inducing\" it to form electron-rich, low-oxidation-state iridium active centers. This “living” structure is precisely the key to efficiently breaking the C-H bonds in propane molecules, that is, flexible activation. 　　“This design of ‘rigid skeleton fixation with flexible electronics modulation’ enables the catalyst to maintain structural stability in harsh environments while exhibiting extremely high activity. ”Song Mingxia, a co-first author of the paper and a doctoral student at the School of Chemical Engineering at Tianjin University, explains the ingenuity in catalyst design in this way. 　　Regarding the potential for industrial application of this achievement, Professor Liu Guozhu, the corresponding author of the paper and head of the team, said, “This catalyst has strong adaptability, and its ‘ultra-long single-run’ property can significantly reduce the frequency of shutdowns and regeneration of existing plants, thereby greatly improving production continuity and operational efficiency.” Leveraging the excellent catalytic properties of this catalyst, it is expected to facilitate the development and design of a new generation of high-efficiency, low-energy-pro consumption propane dehydrogenation units. ”