Facile fabrication of 3D hollow porous aminopyridine rings decorated polymeric carbon nitride for enhanced photocatalytic hydrogen evolution and dye elimination

In consideration of energy shortages and environmental pollution, there is a critical need to develop a photocatalyst with high catalytic performance for rapid hydrogen production and efficient pollutant degradation. We synthesized a photocatalytic composite catalyst with three-dimensional (3D) porous aminopyridine rings grafted on the edge of g-C₃N₄ (APCN) using melamine, cyanuric acid and 4-aminopyridine as raw materials. The composite catalyst exhibited excellent photocatalytic performance for H₂ production (2.44 mmol g⁻¹h⁻¹) and RhB degradation (97.08%) under visible light. Subsequently, a possible enhanced mechanism of the catalyst was proposed on the basis of a series of characterization and photocatalytic experiments. The 3D porous structure not only enhanced the structural stability but also increased the surface area of the APCN catalysts, which generated more exposed active sites. Moreover, the aminopyridine ring embellishment was beneficial for achieving a narrowed bandgap and charge migration and separation, which decreased the occurrence of photogenerated carrier recombination. In summary, these two structural features showed a synergistic effect to enhance the photocatalytic performance of the APCN catalyst. Finally, an integrated feasible enhanced mechanism of photocatalytic activity was elucidated according to the results of active substance capture tests, showing that O₂^•− played an important role during RhB degradation.