Topochemical Intercalation of Graphitic Carbon Nitride with Alkali Metals in Ethylenediamine

Abstract

We studied the intercalation chemistry of graphitic carbon nitride (gCN), combining theory and experimental methods. A series of new alkali-ethylenediamine-gCN products were prepared using a one-pot topochemical synthesis method. Spectroscopic and thermal analyses showed that single-stage intercalated gCN compounds of Li-(ethylenediamine)(0.2) (C3N4.5H1.5)(1.0) and Na(ethylenediamine)(0.3)(C3N4.5H1.5)(0.9) with ordered layer structures were formed. X-ray diffractograms indicated a large gallery expansion of 0.349 and similar to 0.342 nm for Li- and Na-intercalated gCN. In the case of K-en-gCN, a nanocomposite was formed that underwent spontaneous in situ exfoliation followed by disordered restacking to form thin flakes. Molecular dynamics studies showed that ethylenediamine molecules were distributed at the center of the interlayer spaces, predominantly adopting a trans conformation. Different types of gallery sites were present for the intercalation of guest alkali metals, leading to a high degree of topochemical intercalation with organic entities under lower temperatures than previously reported in thermal intercalation experiments. Our new synthesis route enables facile intercalation to tune interlayer spacing in gCN.