Fig. 13

a PL spectra of the aqueous basic solution of terephthalic acid and Fe₃O₄/Ag₃PO₄@WO₃ (0.25, 0.50 and 0.75) with an excitation at 365 nm under different composites for 50 min. Inset of a is the PL spectra of pure sample Ag₃PO₄, WO₃ and Fe₃O₄ and b PL spectra of changing with irradiation time for the case of the Fe₃O₄/Ag₃PO₄@WO₃-0.25