Photocatalytic\nPapers Comprising Au@SnO<sub>2</sub> Nanocrystals Immobilized on Cellulose\nNanofibers for Sustainable\nDye Degradation

This work presents\nthe synthesis, characterization, and\nphotocatalytic\nperformance of a sophisticated photocatalytic paper comprising Au@SnO<sub>2</sub> core@shell nanocrystals immobilized on cellulose nanofibers\n(CNF). The Au@SnO<sub>2</sub>/CNF nanocrystal immobilized paper (NIP)\nis employed as photocatalysts for degradation of rhodamine B (RhB)\nunder simulated sunlight irradiation. Results reveal that the Au@SnO<sub>2</sub>/CNF NIP exhibits a notable photocatalytic activity driven\nby efficient charge separation at the interface of Au and SnO<sub>2</sub>. Mechanistic insights into the degradation process indicate\nthat photoexcited electrons in the Au core reduce dissolved oxygen\nto form superoxide radicals, while photogenerated holes in the SnO<sub>2</sub> valence band oxidize water to generate hydroxyl radicals.\nThese reactive oxygen species, along with the separated holes themselves,\ncontribute to RhB degradation. Importantly, the Au@SnO<sub>2</sub>/CNF NIP demonstrates remarkable recyclability toward RhB degradation,\nretaining 88% of its initial activity after 18 degradation cycles,\nhighlighting its potential for sustainable environmental remediation\napplications.