Fig. 5. (a) Schematic representation of the photo Fenton reaction. (b) UV-vis spectra of MB solutions treated with or without H₂O₂ and FeND and FeND–DOX with or without the 808 nm laser for 20 min. (c) Degradation rate of MB treated with H₂O₂, FeND, and FeND–DOX at intervals of 5 min for 20 min with or without laser. FeND and FeND–DOX exposed to laser showed significant MB degradation when exposed to laser.