Photocatalytic Papers Comprising Au@SnO₂ Nanocrystals Immobilized on Cellulose Nanofibers for Sustainable Dye Degradation

This work presents the synthesis, characterization, and photocatalytic performance of a sophisticated photocatalytic paper comprising Au@SnO₂ core@shell nanocrystals immobilized on cellulose nanofibers (CNF). The Au@SnO₂/CNF nanocrystal immobilized paper (NIP) is employed as photocatalysts for degradation of rhodamine B (RhB) under simulated sunlight irradiation. Results reveal that the Au@SnO₂/CNF NIP exhibits a notable photocatalytic activity driven by efficient charge separation at the interface of Au and SnO₂. Mechanistic insights into the degradation process indicate that photoexcited electrons in the Au core reduce dissolved oxygen to form superoxide radicals, while photogenerated holes in the SnO₂ valence band oxidize water to generate hydroxyl radicals. These reactive oxygen species, along with the separated holes themselves, contribute to RhB degradation. Importantly, the Au@SnO₂/CNF NIP demonstrates remarkable recyclability toward RhB degradation, retaining 88% of its initial activity after 18 degradation cycles, highlighting its potential for sustainable environmental remediation applications.