High photocatalytic performance of bismuth phosphate and corresponding photodegradation mechanism of Rhodamine B

Submicronic BiPO 4 particles (BiP), synthesized via solid-state reaction process at 500 °C, have shown high-performing photocatalytic activity towards Rhodamine B (RhB) degradation under UV irradiation. To better evidence these observed high performances, other commercial particles of TiO 2 , ZnO, and Bi 2 O 3 were used for comparisons. X-ray diffraction (XRD) was used to characterize all polycrystalline phases. The as-synthesized BiP was single phase crystallizing in a monoclinic structure with space group P2 1 /n. The scanning electron microscopy (SEM) analyses of all samples allowed comparing the different average crystallite sizes. The photodegradation of RhB aqueous solution was studied as a function of time, successively in presence of the BiP, TiO 2 , ZnO, and Bi 2 O 3 photocatalysts. The well-crystallized submicron BiP particles exhibit the highest apparent rate constants compared to commercial materials. The observed photoluminescence emission of these BiP particles under UV excitation can be attributed to specific surface defects. The photocatalytic degradation mechanism of RhB has been proposed in detail using a variety of analytical techniques. Graphical abstract