Porous graphitic carbon nitride with lamellar structure: Facile synthesis via in-site supramolecular self-assembly in alkaline solutions and superior photocatalytic activity

The development of highly active photocatalysts is the primary goal in the field of photocatalysis. We herein first develop a facile and scale up approach to synthesize porous polymeric graphitic carbon nitride (g-C₃N₄) with lamellar structure through thermal polycondensation of supramolecular aggregates. The feature of this approach lies in the directed in-situ self-assembly of cyanuric acid molecules, converted from the hydrolysis of melamine in NaOH solution, with the residual melamine molecules to form supramolecular aggregates, which lead to the formation of porous g-C₃N₄ with lamellar structure. The synthesized lamellar g-C₃N₄ exhibit superior photocatalytic activity as demonstrated by the complete degradation of methylene blue (MB) under one hour’s visible light irradiation, as well as excellent stability with high activity retained after four runs of MB degradation testing. The enhancement in photocatalytic performance can be attributed to its unique lamellar structure with high surface area, narrow bandgap, and efficient separation of photogenerated electron-hole pairs. This work shows that the alkaline solutions can be used as the molecular self-assembly medium and opens a new avenue towards designing highly active g-C₃N₄-based photocatalyts for energy and environmental applications.