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Mo 2 C@3D ultrathin macroporous carbon realizing efficient and stable nitrogen fixation
Science China Chemistry ( IF 10.4 ) Pub Date : 2020-04-27 , DOI: 10.1007/s11426-020-9740-8
Zhiwei Fang , Desiree Fernandez , Nana Wang , Zhongchao Bai , Guihua Yu

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.



中文翻译:

Mo 2 C @ 3D超薄大孔碳实现高效稳定的固氮

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。

更新日期:2020-04-27
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