Photochemical synthesis and enhanced photocatalytic activity of MnOx/BiPO4 heterojunction

Monoclinic BiPO4 with rod-like shape was prepared via a CTAB-assisted hydrothermal route. MnOx nanoparticles were loaded on the surfaces of BiPO4 rods by a photo-deposition process to form MnOx/BiPO4 heterojunctions. The as-prepared samples were characterized by XRD, SEM, TEM, XPS, FL, and UV-Vis diffuse reflectance measurements. The results showed that MnOx nanoparticles were strongly anchored to the surfaces of BiPO4 rods when the mole ratio of Mn to Bi was controlled at a low level, forming MnOx/BiPO4 heterojunctions with effective and sound interfaces. The MnOx/BiPO4 heterojunctions exhibited higher photoactivity than pristine BiPO4 for photodegradation of methyl blue under UV irradiation, which could be attributed to the efficient charge transfer at the heterojunction interfaces. The higher light absorption ability of MnOx/BiPO4 in the range of 300-420 nm compared with pristine BiPO4 was also responsible for the enhanced photocatalytic activities of MnOx/BiPO4 heterojunctions.