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.