Ammonia is a key feedstock of fertilizers for farming and convenient hydrogen carrier as an emerging clean fuel, but industrial ammonium production process, Haber-Bosch reaction, is an energy-intensive process, consuming 1%–2% of global energy and producing 3% global CO₂. Electrochemical nitrogen reduction reaction (NRR) is one of the most promising routes to realize highly efficient NH₃ production under ambient conditions. However, up to now, few precious-metal-free electrocatalysts with desirable catalytic performance have been explored. In this work, Mo₂C nanodots anchored on three-dimensional ultrathin macroporous carbon (Mo₂C@3DUM-C) framework is developed toward significantly enhanced nitrogen reduction reaction. Thanks to the special structural design of 3D ultrathin macroporous carbon and highly active and stable Mo₂C toward N₂ electrochemical reduction, the Mo₂C@3DUM-C framework exhibits a high Faradaic efficiency of 9.5% for NH₃ production at −0.20 V and the yield rate reaches 30.4 µg h⁻¹\({\rm{m}}{{\rm{g}}_{{\rm{M}}{{\rm{0}}_{\rm{2}}}{\rm{C}}}}^{-1}\). Further electrochemical characterizations reveal the enhanced electron transfer and increased electrochemical surface area in the 3D macroporous carbon framework. Moreover, the Mo₂C@3DUM-C electrocatalysts hold high catalytic stability after long-term NRR test. The temperature-dependent yield rate of NH₃ demonstrates that the activation energy of nitrogen reduction on the employed catalyst was calculated to be 28.1 kJ mol⁻¹. Our proposed earth-abundant Mo₂C@3DUM-C demonstrates an alternative insight into developing efficient and stable nitrogen fixation catalysts in acids as alternatives to noble metal catalysts.

氨是农业肥料的主要原料，也是作为新兴清洁燃料的便捷氢载体，但是工业铵生产过程（哈伯-博世反应）是一种能源密集型过程，消耗了全球能源的1％–2％，产生的3％全球CO ₂。电化学氮还原反应（NRR）是在环境条件下实现高效NH ₃生产的最有希望的途径之一。但是，迄今为止，几乎没有开发出具有期望的催化性能的无贵金属的电催化剂。在这项工作中，Mo ₂ C纳米点锚固在三维超薄大孔碳（Mo ₂C @ 3DUM-C）构架旨在显着增强氮还原反应。得益于3D超薄大孔碳的特殊结构设计以及对N ₂电化学还原具有高活性和稳定性的Mo ₂ C ，Mo ₂ C @ 3DUM-C骨架在−0.20 V的条件下对NH _3的生产表现出9.5％的高法拉第效率。并且产量达到30.4 µg h ^-1 \（{\ rm {m}} {{\ rm {g}} _ {{\ rm {M}} {{\ rm {0}} _ {\ rm {2 }}} {\ rm {C}}}} ^ {-1} \）。进一步的电化学表征揭示了3D大孔碳骨架中增强的电子传递和增加的电化学表面积。而且，Mo ₂经过长期的NRR测试，C @ 3DUM-C电催化剂具有很高的催化稳定性。NH ₃的随温度变化的产率表明，所用催化剂上氮还原的活化能经计算为28.1 kJ mol ^-1。我们提出的地球上富裕的Mo ₂ C @ 3DUM-C展示了在开发高效，稳定的酸固氮催化剂作为贵金属催化剂替代品方面的另一种见识。