Synthesis of heteroatom-doped nanoporous carbons using zeolite template and their electrochemical application

Abstract

Recently, heteroatom-doped nanoporous carbons have attracted a great deal of attention in the research field of electrochemical applications. However, a more rigorous research is still needed to determine the reaction mechanism and active sites involved with the heteroatom-doped carbons. The synthesis of heteroatom-doped carbons often requires high carbonization temperature, making the control over dopant bonding configurations and the structure of the carbon difficult. As a result, designing a reasonable model to identify the individual effect of different dopant species has been challenging. In this thesis, N-doped carbons having a high content of N with various distributions of N species and an identical 3D graphene-like microporous structure were synthesized using zeolite as a template. Using $Ca^{2+}$ ion catalysts embedded inside the zeolite framework, the carbonization temperature could be lowered down to $500^\circ C$, and the modulation of the N species substituted in the carbon could be achieved by changing the carbonization temperature. These N-doped carbons were used to investigate the efficiency of each N species on the oxygen reduction reaction, without the influences from the porous structure of the carbons. The results indicate that the graphitic N was more effective in enhancing the oxygen-reduction performance of the 3D microporous carbons than pyridinic N.