Reexamination of Solvothermal Synthesis of Layered Carbon Nitride

Abstract

“Graphitic carbon nitride” synthesized by the solvothermal reaction between cyanuric chloride (C ₃N ₃Cl ₃) and sodium amide (NaNH ₂), which was one of the most common methods reported so far, was carefully examined by several analytical techniques for its chemical and structural characteristics. The chemical quantification by the electron microprobe and combustion methods showed that the product synthesized has a significant amount of hydrogen with a composition C ₃N ₅H ₃. Moreover, we found by FT-IR and IR-Raman measurements that the product consists mainly of stacked s-triazine units on the basis of the structural framework of cyanuric chloride, suggesting that s-triazine-based carbon nitride is more stable than heptazine-based one under a mild temperature condition (~200°C). The present study clearly demonstrates that hydrogen-free, pure graphitic C ₃N ₄ cannot be produced by the present solvothermal reaction proposed by the earlier study.