Zhang Chongmin, Fu Xiaolong, Yan Qilong, Li Jizhen, Fan Xuezhong, Zhang Guofang
Xi'an Modern Chemistry Research Institute Xi'an 710065 China.
Key Laboratory of Applied Surface and Colloid Chemistry, MOE/School of Chemistry and Chemical Engineering, Shaanxi Normal University Xi'an 710062 China
RSC Adv. 2019 Oct 16;9(57):33268-33281. doi: 10.1039/c9ra04187g. eCollection 2019 Oct 15.
Graphene oxide (GO) has a catalytic effect on the thermal decomposition of energetic materials above the melting point. To further enhance the catalytic activity of GO, it has been functionalized with the high nitrogen ligand triaminoguanidine (TAG). However, theoretical studies on the reactivity of functionalized GO (, GO-TAG) have not been carried out. Therefore, the thermal decomposition of each TAG, GO and GO-TAG is studied by molecular dynamic simulations using a reactive force-field (ReaxFF) with experimental verification, and the results are reported herein. The results show that the GO nanolayer has a tendency to aggregate into a large carbon cluster during its degradation. The main decomposition products of TAG are NH, N and H. For GO-TAG, the main decomposition products are HO, NH, N and H. GO has a significant acceleration effect on the decomposition process of TAG by decreasing the decomposition temperature of TAG. This phenomenon is in agreement with the experimental results. The initial decomposition of TAG is mainly caused by hydrogen transfer in the molecule. The edge carbon atoms of GO promote the decomposition of TAG molecules and reduce the decomposition activation energy of TAG by 15.4 kJ mol. Therefore, TAG will quickly decompose due to the catalytic effect of GO. This process produces a "new" GO that catalyzes the decomposition of components such as TAG. At the same time, many free radicals (HN, HN and free H) are generated during the decomposition of TAG to catalyze the decomposition of other components, which in turn, enhance the catalytic capability of GO.
氧化石墨烯（GO）对熔点以上的含能材料热分解具有催化作用。为进一步提高GO的催化活性，已用高氮配体三氨基胍（TAG）对其进行功能化。然而，尚未对功能化GO（即GO-TAG）的反应性进行理论研究。因此，本文通过使用反应力场（ReaxFF）的分子动力学模拟研究了每种TAG、GO和GO-TAG的热分解，并进行了实验验证，现将结果报告如下。结果表明，GO纳米层在降解过程中有聚集成大碳簇的趋势。TAG的主要分解产物是NH、N和H。对于GO-TAG，主要分解产物是HO、NH、N和H。GO通过降低TAG的分解温度对TAG的分解过程有显著的加速作用。这一现象与实验结果一致。TAG的初始分解主要是由分子内的氢转移引起的。GO的边缘碳原子促进了TAG分子的分解，并使TAG的分解活化能降低了15.4 kJ/mol。因此，由于GO的催化作用，TAG将迅速分解。这个过程产生了一种“新的”GO，它催化TAG等成分的分解。同时，TAG分解过程中产生许多自由基（HN、HN和游离H），催化其他成分的分解，进而增强了GO的催化能力。
