Interfacial H-Bond Self-Assembly of Cellulose Nanocrystal/Graphitic Carbon Nitride Aerogel for Ultrafast Charge Transport and Efficient Water Purification

Developing scalable, low-cost, eco-friendly photocatalysts with high efficiency and stability remains a major challenge for environmental remediation. Herein, a robust interfacial H-bond self-assembled cellulose nanocrystal/g-C3N4 (CNC/CN) aerogel is designed via a green one-step, in situ fabrication strategy, carried out in aqueous media without the application of organic solvents or additional cross-linkers. The self-assembled H-bond networks between CNC and CN significantly enhance charge transport and visible-light utilization. Benefiting from its hierarchical porosity, enhanced active site exposure, and accelerated electron–hole separation, the resulting CNC/CN aerogel exhibits remarkably promoted photocatalytic activity toward organic wastewater degradation, exceeding pristine CN by 8.0-fold. Scavenger experiments reveal that the synergy of CNC and CN boosts the generation of superoxide radicals (•O2–), enabling an efficient photocatalytic reaction pathway. Furthermore, the aerogel offers recyclability, allowing easy recovery after water treatment. The charge transfer mechanism was analyzed in detail through various characterizations. This work provides a sustainable, scalable, and green route to construct biomass-derived photocatalysts for advanced environmental remediation.