Synthesis and Stabilization of Cubic Gauche Polynitrogen under Radio-Frequency Plasma
Synthesis and Stabilization of Cubic Gauche Polynitrogen under Radio-Frequency Plasma
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DOI：
10.1021/acs.chemmater.2c00689
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发表时间：
2022-05
影响因子：
8.6
通讯作者：
Haizheng Zhuang;Safa Alzaim;Skywalker Li;El Mostafa Benchafia;Joshua Young;N. Ravindra;Z. Iqbal
中科院分区：
文献类型：
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作者：
Haizheng Zhuang;Safa Alzaim;Skywalker Li;El Mostafa Benchafia;Joshua Young;N. Ravindra;Z. Iqbal
立方多氮化合物（cgPN）由于其能量密度高，是TNT能量的3.5倍而备受关注。cgPN已经在理论上进行了详细的研究，但很少有实验研究报告。2004年，cgPN首次在极高温度和高压条件下由氮气合成，一旦释放压力，高压容器中的痕量cgPN就会分解。直到最近，我们的小组首次在环境条件下用射频等离子体从NaN 3前体合成了cgPN。在这里，cgPN的合成和稳定性进行了系统的研究计算和实验。研究了几个主要因素的影响，并探索了可能的关键中间体。除了NaN 3之外，还使用ZEZ N8前体。采用循环伏安法合成了ZEZ N8。根据傅里叶变换红外光谱和拉曼光谱以及ZEZ N8前体的较高产率，发现埃泽N8是合成cgPN的潜在中间体。Na+显示在环境条件下稳定cgPN;然而，过量的Na+对cgPN生长具有负面影响。使用cgPN作为阴极催化剂进行了氧还原反应（ORR），结果表明它对ORR非常活跃，与商业Pt/碳催化剂相当。此外，cgPN在ORR期间显示出优异的稳定性。这项工作指导了cgPN的合理合成和放大及其在ORR中的实际应用。
Cubic gauche polynitrogen (cgPN) has been very attractive because of its high energy density that is 3.5 times of the TNT energy. cgPN has been investigated theoretically in detail, but few experimental studies have been reported. In 2004, cgPN was first synthesized from nitrogen gas under extremely high temperature and high pressure conditions and the trace amount of cgPN in the high-pressure vessel decomposed once the pressure was released. Until recently, our group for the first time synthesized cgPN from an NaN3precursor under ambient conditions with radio-frequency plasma. Here, synthesis and stabilization of cgPN are systematically investigated both computationally and experimentally. The effects of several major factors are studied, and the possible key intermediate is explored. In addition to NaN3, a ZEZ N8precursor is also used. ZEZ N8was synthesized by the cyclic voltammetry method. EZE N8is found to be the potential intermediate for cgPN formation based on the Fourier transform infrared and Raman spectra and the fact that a higher yield of cgPN is obtained with the ZEZ N8precursor. Na+is shown to stabilize cgPN under ambient conditions; however, an excess of Na+has a negative effect on cgPN growth. The oxygen reduction reaction (ORR) was carried out using cgPN as the cathodic catalyst, and the result shows that it is very active for the ORR, which is comparable with a commercial Pt/carbon catalyst. Moreover, cgPN shows an excellent stability during the ORR. This work guides the rational synthesis and scaleup of cgPN and its practical applications for the ORR.