Nanoflower-like graphitic carbon nitride aerogel: Artful cyanuric acid-controlled synthesis and enhanced...

The previously reported studies on cyanuric acid-assembly strategy usually ignores the promoting function of cyanuric acid in the production of g-C₃N₄, 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-C₃N₄) aerogel. Some cyanuric acid molecules underwent a polycondensation reaction with melamine during the pre-assembly process and finally polymerized into the g-C₃N₄ 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 (CO) and hydroxyl (-OH) groups onto the g-C₃N₄ surface, resulting in the successful generation of a 3D nanoflower-like oxygen-modified g-C₃N₄ aerogel. Moreover, the fabricated g-C₃N₄ aerogel exhibited a greatly enhanced H₂ production rate (1573 μmol h^-1 g^-1), which is ∼ 6.6 times higher than that of bulk g-C₃N₄ (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-C₃N₄ photocatalysts via molecular assembly.