A rod-shaped Bi2MoO6/Bi14MoO24 homoelemental heterojunction for efficient degradation of tetracycline

Bismuth molybdate has attracted extensive attention as a visible semiconductor photocatalyst with great application potential, but bismuth molybdate is suffering rapid charge recombination and lower catalytic activity. Therefore, a rod-shaped Bi 2 MoO 6 /Bi 14 MoO 24 homoelemental heterojunction was successfully fabricated using hydrothermal treatment and high-temperature calcination combined method. This novel heterojunction shows an excellent photocatalytic activity and good stability. Degradation efficiency of the optimal catalysts is up to 86 % under visible light for 100 min, and remained above 80 % after four cycles. Kelvin probe force microscopy (KPFM) is adopted to further verify faster separation of photogenerated carriers on Bi 2 MoO 6 /Bi 14 MoO 24 heterogeneous nanorods. The result of DFT calculations also further proves that Bi 2 MoO 6 /Bi 14 MoO 24 homoelemental heterojunction has higher work function and lower Fermi level, which can prolonging photogenerated electrons and holes lifetimes. Free radical capture experiments suggest that super oxide anion (•O 2 - ) and hydroxyl (•OH) are main active groups during photocatalytic degradation, which is proved by EPR result. Considering this, a possible S-scheme mechanism is proposed to illustrate this enhanced performance. This research enriches heterojunction system and provides a reference for the design of efficient photocatalysts in future.