Synthesis of Dual Z-Scheme CuBi2O4/Bi2Sn2O7/Sn3O4 Photocatalysts with Enhanced Photocatalytic Performance for the Degradation of Tetracycline under Visible Light Irradiation

The dual Z-scheme heterojunction CuBi2O4/Bi2Sn2O7/Sn3O4(CBS) was successfully constructed through in situ growth methods, and its photocatalytic performance was evaluated via degradation of tetracycline hydrochloride under visible light. Out of all samples, CBS-2 exhibited the highest photocatalytic activity, with an apparent rate constant of 2.34, 20.16, and 44.17 times that of Bi2Sn2O7, CuBi2O4, and Sn3O4, respectively. Even after four cycles, the photocatalytic efficiency remained above 85%. The improvement can be attributed to the construction of the Z-scheme heterojunction, which effectively promotes the separation and migration of photogenerated carriers. The possible photocatalytic degradation mechanism of dual Z-scheme heterojunction CBS was deduced based on the theory of free radical capture and energy band.