The development of advanced photocatalytic materials is essential to address persistent pharmaceutical contaminants in aquatic ecosystems. In this work, we engineer a three-dimensional (3D) aerogel by coupling phosphorus-doped graphitic carbon nitride (PgCN) nanosheets with reduced graphene oxide (rGO), designed for efficient visible light driven degradation of tetracycline (TC). Incorporating phosphorus into the carbon-nitrogen matrix of g-C3N4 optimizes its photocatalytic efficacy by reducing the bandgap, broadening visible-light absorption, and accelerating charge carrier dynamics. The synergistic integration of PgCN with rGO into a 3D macroassembly imparts buoyancy, enabling practical deployment at the water-air interface. The resultant aerogel demonstrates exceptional TC degradation efficiency (>92% within 120 min), surpassing pristine g-C3N4 by nearly threefold. Enhanced performance is attributed to the hierarchical porosity, extended surface area, and improved electron-hole separation enabled by PgCN. Crucially, the material shows resilience against varying water salinity and coexisting mono-/divalent cations, retaining its catalytic activity. Furthermore, the aerogel exhibits outstanding recyclability, sustaining >88% efficiency over five cycles without structural deformations. This study underscores the potential of the floating PgCN-rGO aerogel as a scalable, solar-driven solution for eliminating emerging contaminants in diverse aqueous matrices.
