Synthesis and photocatalytic activity of composite magnetic photocatalyst Mn <sub/>x</sub> Zn <sub/>1-x</sub> Fe <sub/>2</sub> O <sub/>4</sub> /α-Bi <sub/>2</sub> O <sub/>3</sub>

摘要： In this paper, a new magnetic photocatalyst MnxZn1-xFe2O4/α-Bi2O3 is synthesized by the dip-calcination technology, using manganese zinc ferrite as a magnetic substrate. It is beneficial to separate the composite from liquid solution under an extra magnetic field. This heterojunction of composite MnxZn1-xFe2O4/α-Bi2O3 presents remarkable photocatalytic activity and prominent photocatalysis for degradation of Rhodamine B (RhB), far exceeding the pure α-Bi2O3. Especially, the introduction of MnxZn1-xFe2O4 not only reduces the bandgap of photocatalyst α-Bi2O3, but also improves its response in the visible region. Importantly, the magnetic photocatalyst is capable of being used repeatedly, and the photocatalytic activity would remain above 90% after 3 cycles. Such an outstanding stability and retrievability of composite are mainly ascribed to the soft-magnetic material MnxZn1-xFe2O4, enhancing separation of photoinduced electron hole pairs. This work will replace the traditional semiconductor photocatalyst for a convenient recycling and removal of contaminants from wastewater in the future.