Nanosheets loaded on tetrahedral surfaces form a Z-type Bi2MoO6/gamma-Bi2O3 heterojunction to enhance the photocatalytic degradation activity of lomefloxacin and Rhodamine B

The Bi2MoO6 nanosheets are loaded on to gamma-Bi2O3 tetrahedron surfaces to form Bi2MoO6/gamma-Bi2O3 heterojunctions using a simple calcination method. The photocatalytic degradation efficiencies of the lomefloxacin and the Rhodamine B using the optimum sample are 96% and 99%, respectively, much higher than that of pure phase samples. When the waters from different regions in China were used as solvents, the removal efficiencies of the lomefloxacin and the Rhodamine B are still higher than 88% and 90%, respectively, which shows excellent prospects for practical applications. The photocatalytic degradation efficiencies of these two pollutants are higher than 91% and 95% in the five cycling tests, and the crystal structure of the sample is not changed after cycling. Based on the first-principles calculation, Bi2MoO6 and gamma-Bi2O3 form a Z-type energy band structure which accelerates the separation of the photogenerated charge carriers. The Bi2MoO6 valence band potential of 3.25 V and the gamma-Bi2O3 conduction band potential of -0.21 V are reserved to generate OH- and O-2(-), respectively, for the photocatalytic reaction. The degradation of the lomefloxacin is ascribed to the shedding of functional groups and bond breaking with the final products being CO2, F-, H2O, and NO3-. This research shows that Bi2MoO6/gamma-Bi2O3 heterojunctions can be employed to purify domestic and textile industrial sewage.