【Frontiers in HaiChuan Chemical Technology】Dalian Institute of Chemical Physics develops a plasma-enhanced palladium membrane reactor coupling system for hydrogen production via low-temperature ammonia decomposition

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The plasma-enhanced palladium membrane reactor coupling system I developed for hydrogen production via low-temperature ammonia decomposition. Published on: 2025-11-13. Recently, Researcher Li Hui from our institute’s Research Group on Carbon Resources, Small Molecules, and Hydrogen Energy Utilization (Group DNL1905), in collaboration with Professor Liu Yi, Associate Professors Cui Zhaolun, and Yi Yanhui from Dalian University of Technology, developed a new type of plasma-enhanced dual-membrane ammonia decomposition system (PEDMADS). This system cleverly integrates low-temperature plasma catalysis technology, high-performance ultra-thin palladium (Pd) membranes, and S-1 molecular sieve membranes for ammonia recovery; under mild conditions of 400 ℃, it achieves a space-time yield of hydrogen (H2) of 1567 mmol g-1 h-1, providing a new pathway for an efficient and sustainable ammonia-hydrogen energy cycle. Ammonia (NH3), as a major zero-carbon hydrogen carrier, will play an important role in future sustainable energy systems. However, traditional catalytic ammonia decomposition technologies are constrained by thermodynamic and kinetic limitations; they usually require high temperatures of over 550 °C, resulting in high energy consumption and easy sintering of the catalysts. Membrane reactor technology, which combines reaction and in-situ product separation, is an effective strategy to address this challenge. Among them, palladium (Pd)-based composite membranes, due to their excellent selective permeability to H2, can remove the product H2 in situ, breaking the equilibrium constraints of the reaction and thereby increasing the one-way conversion rate of ammonia. However, traditional thermally driven palladium membrane reactors are still limited by the insufficient activity of the catalyst at low temperatures. In this work, one of the core materials of the PEDMADS system developed by the collaborative team is the high-performance ultra-thin palladium film developed by Li Hui and others. This palladium film was prepared by electroless plating on the inner surface of a porous α-alumina (α-Al2O3) substrate, resulting in a dense, high-purity palladium metal layer with a thickness of 1.8 μm, which is significantly lower than that of conventional capillary palladium tubes (typically greater than 50 μm). In the reactor, this palladium membrane acts as an efficient \"hydrogen pump\", capable of continuously removing the product H2 from the reaction zone in situ. Another key material in the PEDMADS system is the ruthenium/silica (Ru/SiO2) catalyst prepared using low-temperature plasma (DBD) in combination with ALD technology, developed by Liu Yi’s team. Studies have found that plasma efficiently activates NH3 under mild conditions of 400 ℃ (with a conversion rate of 52.1%), and the high pressure of H2 generated provides a driving force for the permeation through the palladium membrane ； The timely removal of the palladium membrane, in turn, disrupted the reaction equilibrium, resulting in a further relative increase of 24.8% in the NH3 conversion rate based on the plasma level, ultimately reaching 65.0%. This strong synergistic effect between “plasma catalysis” and “palladium membrane separation” enhances the low-temperature ammonia decomposition process, increases the H2 yield, and reduces the system’s energy consumption. In addition, the system also incorporates a downstream S-1 molecular sieve membrane cascade module for the efficient recovery of unreacted NH3 (with a recovery rate of over 87%), thereby achieving a closed-loop circulation of the raw materials. Techno-economic analysis shows that, compared to traditional thermal processes, this integrated system can reduce the carbon footprint by 95.9%, and it has the potential to meet the green H2 cost targets set by the U.S. Department of Energy (DOE), indicating excellent prospects for industrial application. Building on previous series of studies such as the palladium membrane reactor for ammonia decomposition (Chem. Eng. J., 2020) and the preparation of ultra-thin palladium membranes (J. Mater. Chem. A, 2025), this work further demonstrates the key synergistic role of high-performance palladium membranes in novel plasma-coupled reaction systems. Previously, Li Hui and her colleagues developed a number of new technologies and processes for the preparation of ultra-thin palladium membranes to address the key issues in their industrial application. More than 80 palladium membrane purifiers were supplied for the production of materials such as chips and diamonds. These products have obtained EU and CNAS certifications, and they have been operating without any failures for over three years. This technology has been included in the **New Materials Industry Development Professional Advisory Committee’s Catalogue of Innovations in Industrial Infrastructure** issued by the Ministry of Industry and Information Technology, as well as on the list of \"scientific instruments developed independently by the Chinese Academy of Sciences\" for 2025.