Monolithic AgX/Biomass Carbon Aerogels (X = Br, Cl) for Recyclable Photocatalytic Degradation of Multiple Pollutant Classes.

While silver halides (AgX) are promising visible-light photocatalysts for water remediation, their practical deployment is severely hindered by intrinsic photocorrosion, rapid charge recombination, and macroscopic recovery challenges. Here, we demonstrate a monolithic AgX/biomass carbon aerogel composite platform, constructed by anchoring AgX nanocrystals in situ onto a 3D hierarchical carbon skeleton. The carbon network not only suppresses nanoparticle aggregation but also plays contrasting optical roles: amplifying the intrinsic visible-light absorption of AgBr while endowing the otherwise UV-confined AgCl with substantial visible-light response. Consequently, the optimal 30 wt% AgBr/CA composite achieves a 95.68% methylene blue degradation efficiency within 60 min-outperforming pristine AgBr by 2.6-fold-while establishing robust activity against two additional, structurally distinct pollutants: rhodamine B and the colorless antibiotic ciprofloxacin. Notably, the free-standing monolith retains exceptional activity over six consecutive cycles. Mechanistic investigations reveal that the carbon aerogel functions as an electron-accepting reservoir, which accelerates interfacial charge separation and steers electron flow toward superoxide radical generation. Notably, XRD and XPS analyses confirm that no detectable metallic Ag