C₂N: A Class of Covalent Frameworks with Unique Properties

Abstract

C 2 N is a unique member of the C n N m family (carbon nitrides), i.e., having a covalent structure that is ideally composed of carbon and nitrogen with only 33 mol% of nitrogen. C 2 N, with a stable composition, can easily be prepared using a number of precursors. Moreover, it is currently gaining extensive interest owing to its high polarity and good thermal and chemical stability, complementing carbon as well as classical carbon nitride (C 3 N 4) in various applications, such as catalysis, environmental science, energy storage, and biotechnology. In this review, a comprehensive overview on C 2 N is provided; starting with its preparation methods, followed by a fundamental understanding of structure-property relationships, and finally introducing its application in gas sorption and separation technologies, as supercapacitor and battery electrodes, and in catalytic and biological processes. The review with an outlook on current research questions and future possibilities and extensions based on these material concepts is ended.

Understanding Structure–Property Relationships under Experimental Conditions for the Optimization of Lithium‐Ion Capacitor Anodes based on All‐Carbon‐Composite Materials

“…[25] Condensation of bulk HAT-CN at 700 C or below leads to the formation of a C 2 N-like material with a high content of pyrazinic nitrogen. [31][32][33] In contrast, the material obtained from HAT-CN condensation at 1000 C is a rather ordinary N-doped carbon with a lower overall nitrogen content, mainly bonded in graphitic structure motives. Thermogravimetric analysis (TGA) curves of the ZTC infiltrated with different amounts of HAT under N 2 and synthetic air atmosphere are shown in Figure S1a, Supporting Information.…”

A Reanalysis of the Diverse Sodium Species in Carbon Anodes for Sodium Ion Batteries: A Thermodynamic View

“…For example, inspired by the high-performance N-doped carbon materials for SIBs, carbon nitrides, especially the less studied members with small band gaps (C 2 N 2 , C 2 N, C 3 N …) are promising candidates. [101,119] This class of carbon-based materials possesses higher percentage of N heteroatoms, which are inherently tunably porous, show high electronic conductivity, and provide rich structural features to target the optimized electrochemical performance. The strong polarization on the pore walls of such carbon nitrides and pore structures in the quantum dot size also reduces the melting point of sodium, as reported by our recent studies, [120] and thus enables a liquid electron storage metal.…”

Recent Progress in Polymorphs of Carbon Nitride: Synthesis, Properties, and Their Applications

“…[ 19 ] The core‐structure of PAHs and GNR, however, consists of continuous conjugated CC linkages, different from the PCN materials. Furthermore, C 3 N [ 20 ] and C 2 N [ 21 ] are new members of a carbon nitride family with covalent structures composed of carbon and nitrogen atoms, which are distinguishable from PCN type materials. Nevertheless, unraveling every polymeric form by elucidating their structural features is a bottleneck for a better understanding of newer allotropes of CN.…”