Highly N-doped and crystalline hetero-carbon materials through solution plasma and its application

Nitrogen-doped (N -doped) carbon has been used for various energy conversion applications. However, there are still unclear how to select effective conditions to controllably synthesize the required N -doped carbon in plasma-based technologies. We used systemic methodology explored the correlation between patterns of optical emission spectroscopy (OES) and carbon products under solution plasma (SP). Fifty-three types of $\sigma$-and $\pi$-bonded precursors, including five- and six-member ring molecules, were utilized as raw materials in bipolar- or unipolar-pulsed discharge and indicated four different patterns of OES with H, C
2
, CN, and C
2
/CN dominations from plasma zone. The intermediates from solution zone were characterized by GC/MS and the potential information of the plasma/gas/liquid interface zone was characterized by electrostatic probe. The founded evidence proved that C
2
served to repair defects during graphene formation, thus contributing to the enhancement of the crystallinity of the carbons. CN had a specific sp or sp
³
structure, which consequently introduced more defects in the graphene framework. The results confirmed that the emission profile might provide underlying insights and could be the guideline for the conversion of cyclic-structured organic molecules to different carbon structures toward a performance target.