Fig. 1

Luminescence spectra of nanoceria under different conditions. a 10.0-nm nanoceria before and 25 min after HP (C = 0.1 mM) addition. Insert: normalized spectra of different nanoceria samples. b Luminescence spectra of 10.0-nm nanoceria before and after addition of 50 and 80 μl of dye. Insert: spectra of 10.0-nm nanoceria after addition of 50 μl of dye and subsequent addition of HP (C = 0.1 mM)