Nitrogen Reduction Reaction
Nitrogen Reduction Reaction
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DOI：
10.1002/smtd.201900070
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发表时间：
2019-06
期刊：
影响因子：
12.4
通讯作者：
Gengfeng Zheng;Jun-min Yan;Guihua Yu
中科院分区：
文献类型：
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作者：
Gengfeng Zheng;Jun-min Yan;Guihua Yu
DOI: 10.1002 / smtd。201900070在2.0 V电池电压下获得8.9× 10−11 mol s−1 cm−2和15.56µg h−1 mg−1 cat，在1.8 V电池电压下获得6.7%的法拉第效率。作者预测氮化氧铬的NRR遵循Mars-van Krevelen机制，氧对氮原子电子性质的协同作用有利于氮在CrO0上的还原。66 n0。56表面。这项工作表明，金属氮基材料可能是NRR的有希望的候选者，并且通过部分氧化调节金属氮的电子特性可以进一步改善其性能。黄林松及其同事（文章号1800386）证明了NbO2可以作为高效的NRR电催化剂用于环境氨合成。由于竞争析氢反应（HER）是在水溶液中高效使用NRR电催化剂的主要障碍，因此作者选择了NbO2，预计NbO2可以以与NRR电催化剂相似的强度结合* NNH和* H来抑制竞争水还原。在酸性溶液中，NbO2纳米颗粒的氨生成速率为11.6µg h−1 mgcat。在−0.65 V时，相对于RHE的法拉第效率为−1，在−0.60 V时，法拉第效率峰值为32%，这是迄今为止报道的最高值之一。与具有相似晶体结构单元但氧化态不同的Nb2O5相比，NbO2中的Nb4+阳离子不仅提供了对N2强吸附的空d轨道，而且还提供了一个单d电子，进一步使π反给能活化吸附的N2分子。因此，在所有测试电位下，NbO2表现出比Nb2O5更好的NRR性能。这项工作表明，调整过渡金属的氧化态可以提高NRR的法拉第效率，并表明对Nb4+基材料的进一步研究可能会导致新的电催化剂用于高效的电催化NRR。Wang Xin-Gai及其同事（文章编号1800334）利用掺n碳纳米片（Mo2C/NC）上的超小Mo2C颗粒作为Li-N2电池的空气阴极。大的比表面积和丰富的介孔使得放电产物能够储存，而Mo2C颗粒则是高效的氮还原电催化剂。掺杂Mo2C/ n碳阴极的Li-N2电池表现出优异的电化学性能，达到未掺杂Mo2C的8倍。值得注意的是，大多数锂空气电池都是在纯O2气氛下进行研究的，但在实际的锂空气电池中，N2的影响往往被忽视。这项工作表明，锂- N2电池是一个有前途的N2电还原和电化学储能平台，并可能为开发更稳定的实际使用的锂-空气电池提供启发。已知氮酶中的铁钼辅助因子（FeMoco）在Mo-Fe-S簇中含有一个神秘的碳原子；蒋亚飞等（文章号1800340）利用DFT和完全活性空间自洽场（CASSCF）方法进行了全面的理论研究，揭示了不同锚定原子对三角双金字塔的影响。氮（N2）是自然界中最丰富、化学惰性最强的分子之一，其转化为氨（NH3）是生产肥料和高效能量载体的基础。长期完善的哈伯-博世方法已经取得了100多年的成功，并为地球上70多亿人提供了支持。然而，这一过程是能源成本密集型的，需要大量的资本和基础设施投资，并且占…
DOI: 10.1002/smtd. 201900070 of 8.9× 10− 11 mol s− 1 cm− 2 and 15.56 µg h− 1 mg− 1 cat achieved at a cell voltage of 2.0 V and a Faradaic efficiency of 6.7% is achieved at a cell voltage of 1.8 V. The authors predict the NRR on chromium oxynitride to follow a Mars–van Krevelen mechanism and the synergistic effect of oxygen on the electronic property of nitrogen atom can facilitate the reduction of N on the CrO0. 66N0. 56 surface. This work indicates that metal nitride–based materials could be promising candidates for NRR and the performance of metal nitrides could be further improved by tuning the electronic properties by partial oxidation. Linsong Huang and co-workers (article number 1800386) demonstrate that NbO2 can act as a highly efficient NRR electrocatalyst for ambient ammonia synthesis. Since the competing hydrogen evolution reaction (HER) is known to be a major obstacle for efficient NRR electrocatalysts in aqueous electrolyte, the authors choose NbO2 which is predicted to bind* NNH and* H with similar strength as the NRR electrocatalyst to suppress the competing water reduction. In acidic solutions, the NbO2 nanoparticles present an outstanding ammonia production rate of 11.6 µg h− 1 mgcat.− 1 at− 0.65 V versus RHE and a peak faradaic efficiency of 32% at− 0.60 V versus RHE, one of the highest reported value to date. Compared to Nb2O5 with a similar crystal structure unit but different oxidation state of niobium, the Nb4+ cation in NbO2 provides not only empty d-orbitals for strong N2 adsorption, but also a single d-electron to further enable π back donation to activate the adsorbed N2 molecules. Therefore, NbO2 exhibits better NRR performance than Nb2O5 at all tested potentials. This work demonstrates that tuning of oxidation states of transition metals could enhance the faradaic efficiency of NRR and indicates that further investigations on the Nb4+-based materials may lead to new electrocatalytsts for efficient electrocatalytic NRR. Xin-Gai Wang and co-workers (article number 1800334) utilize ultrasmall Mo2C particles on N-doped carbon nanosheets (Mo2C/NC) as air cathodes for Li–N2 batteries. The large specific surface area and abundant mesopores enable storage of discharge products, while Mo2C particles act as efficient nitrogen reduction electrocatalyst. The Li–N2 batteries with Mo2C/N-doped carbon cathodes show an excellent electrochemical performance, reaching up to eightfold of that without Mo2C. Notably, most Li–air batteries were investigated under a pure O2 atmosphere, but the influence of N2 is often neglected for practical Li–air batteries. This work demonstrates that the Li–N2 battery is a promising platform for N2 electroreduction and electrochemical energy storage and may shed light on the development of more stable Li–Air batteries for practical use. It is known that iron-molybdenum cofactor (FeMoco) in nitrogenase contains an enigmatic carbon atom in the Mo-Fe-S cluster; Ya-Fei Jiang et al.(article number 1800340) carried out a comprehensive theoretical study using DFT and complete active space self-consistent field (CASSCF) methods to unveil the influence of different anchor atoms of trigonal bipyramidalThe conversion of nitrogen (N2), one of the most abundant and chemically inert molecules in nature, into ammonia (NH3), is the foundation of producing fertilizers and efficient energy carriers. The long-standing and well-established Haber-Bosch process has marked over 100 years of success and been sustaining over 7 billion of people on earth. Nonetheless, this process is energy-cost intensive, requires high capital and infrastructure investment, and accounts for a significant amount of …