Nanoflower-like graphitic carbon nitride aerogel: Artful cyanuric acid-controlled synthesis and enhanced photocatalytic hydrogen evolution activity

The previously reported studies on cyanuric acid-assembly strategy usually ignores the promoting function of cyanuric acid in the production of g-C 3 N 4 , limiting the development of molecular assembly strategies. In this study, a cyanuric acid-controlled synthesis strategy involving the pre-assembly of cyanuric acid with melamine and subsequent one-step calcination was developed to produce a three-dimensional (3D) nanoflower-like graphitic carbon nitride (g-C 3 N 4 ) aerogel . Some cyanuric acid molecules underwent a polycondensation reaction with melamine during the pre-assembly process and finally polymerized into the g-C 3 N 4 structure during subsequent calcination. Meanwhile, the remaining cyanuric acid molecules assembled with melamine via hydrogen-bond interactions and underwent incomplete decomposition during subsequent calcination, which not only promoted the production of 3D nanoflower-like aerogel structures, but also introduced the carbonyl (C O) and hydroxyl (–OH) groups onto the g-C 3 N 4 surface, resulting in the successful generation of a 3D nanoflower-like oxygen-modified g-C 3 N 4 aerogel. Moreover, the fabricated g-C 3 N 4 aerogel exhibited a greatly enhanced H 2 production rate (1573 μmol h −1 g −1 ), which is ∼ 6.6 times higher than that of bulk g-C 3 N 4 (239 μmol h −1 g −1 ) owing to the synergistic promotion function of ultrathin nanoflower-like aerogel and oxygen modification structures. This strategy provides a theoretical basis for the development of highly efficient g-C 3 N 4 photocatalysts via molecular assembly.