Author ORCID Identifier
0000-0002-2805-2449
Document Type
Dissertation
Date of Award
5-31-2022
Degree Name
Doctor of Philosophy in Materials Science and Engineering - (Ph.D.)
Department
Physics
First Advisor
Xianqin Wang
Second Advisor
N. M. Ravindra
Third Advisor
Xiaoyang Xu
Fourth Advisor
Zafar Iqbal
Fifth Advisor
Thelma Gatuz Manning
Abstract
Cubic gauche polynitrogen (cgPN) has been very attractive due to its high energy density that is 2.5 times higher than that of TNT. In the literature, cgPN has been investigated theoretically in detail, but few experimental works have been reported. In 2004, cgPN was first synthesized from nitrogen gas under extremely high temperature and high pressure (HTHP) conditions and the trace amount of cgPN in the high-pressure vessel decomposed once the pressure was released. Until recently, our group was the first to synthesize cgPN from NaN3 precursor under ambient conditions with radio frequency (RF) plasma. In this study, the 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, ZEZ N8 precursor is also used. ZEZ N8 is synthesized by a cyclic voltammetry (CV) method. EZE N8 is found to be the potential intermediate for cgPN formation based on Fourier transform infrared (FTIR) and Raman spectra, and a higher yield of cgPN is obtained with the ZEZ Ng precursor. Na+ is shown to stabilize cgPN under ambient conditions; however, excess of Na+ has a negative effect on cgPN growth. Oxygen reduction reaction (ORR) is carried out using cgPN as the cathodic catalyst; the result shows that it is very active for the ORR, which is comparable to commercial Pt/carbon catalyst. Moreover, cgPN shows an excellent stability during ORR.
In this work, cgPN has been synthesized with RF plasma from NaN3 powder and NaN3 dispersed on carbon nanotubes (CNTs). The results show that both nitrogen and argon plasma can produce cgPN, in which high-energy electrons in plasma is the most important parameter. The density of electrons is important for cgPN synthesis. The highest electron density zone is at the distance of 10 mm to the center and close to the inductive coil along the radial and axial direction, respectively. The electrons in plasma can be exhausted significantly by interacting with NaN3-CNT in the reactor vertically.
This work reports the rational synthesis and its practical applications for ORR.
Recommended Citation
Zhuang, Haizheng, "Synthesis of polynitrogen with radio frequency plasma" (2022). Dissertations. 1926.
https://digitalcommons.njit.edu/dissertations/1926
