Fabrication of two-dimensional CeO ₂ /dealkali lignin nanocomposite for enhanced UV-shielding and antioxidant applications

To overcome the inherent agglomeration and potential nanotoxicity of inorganic UV filters, as well as the environmental concerns associated with organic absorbers, we present a bio-templated strategy utilizing natural dealkali lignin (DL) as sustainable scaffold to direct the in situ growth of sheet-like CeO 2 , resulting in a well-defined two-dimensional CeO 2 /DL layered architecture. At an optimal DL mass ratio of 1.5%, the CeO 2 nanosheets achieve uniform dispersion on the DL matrix, stabilized by hydrogen bonding and C–O–Ce interfacial linkages. The resulting composite exhibits strong ultraviolet absorption while retaining excellent visible transparency, achieving a Sun Protection Factor (SPF) of 8.9 representing a 2.1-fold and 1.7-fold enhancement over pristine DL and pristine CeO 2 , respectively. Moreover, the composite demonstrates remarkable antioxidant activity, with DPPH and hydroxyl radical scavenging efficiencies of 72% and 86%. This work establishes a viable pathway for designing natural, eco-friendly, and high-performance next-generation UV-shielding materials.