[Frontiers in Chemical Technology by Haichuan] Dalian Institute of Chemical Physics achieves ammonia production at industrial-level current density for 1,000 hours! ! !

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Recently, the team led by Bao Xinhe, an academician of the Chinese Academy of Sciences and a researcher at the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, made new progress in the electrochemical synthesis of ammonia. Through an electrochemical in-situ reconstruction strategy, the research team constructed copper-palladium hydride (Cu–PdHx) interfacial active sites for the efficient electrochemical reduction of nitrate to ammonia. This enabled ammonia production at industrial-level current densities for 1,000 hours in membrane electrode electrolytic devices. Additionally, a scale-up demonstration of an ammonia synthesis stack was carried out. The relevant results were published in Nature Synthesis. https://p3-sign.toutiaoimg.com/tos-cn-i-axegupay5k/be5499d4d943426686098f248b62581b~tplv-tt-origin-web:gif.jpeg?_iz=58558&from=article.pc_detail&lk3s=953192f4&x-expires=1766038896&x-signature=%2BWOd%2B3AhbIkrPdk1nE1FMBhcB9k%3D Schematic diagram of electrochemical ammonia synthesis. Photo provided by Dalian Institute of Chemical Physics. Ammonia plays an important role in agricultural production and the next generation of carbon-free energy systems. Electrocatalytic reduction of nitrate (NO3–) to produce ammonia (NH3) driven by renewable energy is an effective approach to decarbonizing ammonia production and enabling the recycling of nitrogen resources. However, slow reaction kinetics and competitive hydrogen evolution reactions are the main challenges in electrochemical ammonia synthesis; developing high-performance catalysts and electrolytic devices is key to improving the performance of electrochemical ammonia synthesis and facilitating its practical application. In this work, the team developed a high-performance copper/palladium (CuPd) catalyst that, under electrochemical reaction conditions, forms Cu–PdHx interfacial sites with high intrinsic activity in situ. The team incorporated the catalyst into an alkaline membrane electrolyzer, achieving efficient NH3 synthesis. Studies found that at a total current density of 5 A cm–2, the ammonia Faradaic efficiency was 85.3%, the cell voltage was 2.56 V, and the NH3 production rate was 19.9 mmol h–1 cm–2. Meanwhile, this reaction can operate stably for 1000 hours at a current density of 2.0 A cm–2. The results of in-situ spectroscopic characterization of the device under operating conditions, combined with density functional theory calculations, show that the formation of a biphasic interface and the in-situ generation of the PdHx phase together enhanced the intrinsic activity of the catalyst. The redistribution of hydrogen species at the Cu–PdHx interface effectively adjusted the local electronic structure of the active sites at the interface, thereby optimizing NO3– adsorption and NH3 desorption. Subsequently, the team developed 5 series-connected membrane electrode electrolyzer stacks with an electrode area of 100 cm2 and carried out an electrochemical ammonia synthesis scale-up demonstration: at a current of 500 A, the NH3 generation rate reached 8.7 mol h–1, and ammonia could be produced continuously at a rate of 1.6 mol h–1 at a current of 100 A for 100 hours.