Thermolytic synthesis of graphitic boron carbon nitride from an ionic liquid precursor: mechanism, structure analysis and electronic properties

Recent work has shown the potential of ionic liquids (ILs) as a precursor for porous networks and nitrogen doped carbon materials. The combination of liquid state and negligible vapour pressure represents almost ideal precursor properties and simplifies the processing drastically. Here, we extend this work to get a deeper insight into the solid formation mechanism and to synthesize a mixed boron carbon nitride species by the thermolysis of N,N'-ethylmethylimidazolium tetracyanoborate (EMIM-TCB), a well-known boron- and nitrogen-containing IL. In contrast to other molecule pyrolysis routes boron carbon nitride shows the average composition BC3N and like other IL-derived materials turns out to be distorted graphitic, but thermally and chemically very stable, and possesses favourable electrical properties. The detailed mechanistic investigation using TG-IR, FT-IR, solid-state NMR, Raman, WAXS, EELS, XPS and HRTEM also contributes to the general understanding of IL-based material formation mechanisms.