Microporous Carbon Nitride (C 3 N 5.4 ) with Tetrazine based Molecular Structure for Efficient Adsorption of CO 2 and Water

Abstract Mesoporous carbon nitrides with C 3 N 5 and C 3 N 6 stoichiometries created a new momentum in the field of organic metal‐free semiconductors owing to their unique band structures and high basicity. Here, we report on the preparation of a novel graphitic microporous carbon nitride with a tetrazine based chemical structure and the composition of C 3 N 5.4 using ultra‐stable Y zeolite as the template and aminoguanidine hydrochloride, a high nitrogen‐containing molecule, as the CN precursor. Spectroscopic characterization and density functional theory calculations reveal that the prepared material exhibits a new molecular structure, which comprises two tetrazines and one triazine rings in the unit cell and is thermodynamically stable. The resultant carbon nitride shows an outstanding surface area of 130.4 m 2  g −1 and demonstrates excellent CO 2 adsorption per unit surface area of 47.54 μmol m −2 , which is due to the existence of abundant free NH 2 groups, basic sites and microporosity. The material also exhibits highly selective sensing over water molecules (151.1 mmol g −1 ) and aliphatic hydrocarbons due to its unique microporous structure with a high amount of hydrophilic nitrogen moieties and recognizing ability towards small molecules.