Fabrication of 3D Bi5O7I/BiOIO3 heterojunction material with enhanced photocatalytic activity towards tetracycline antibiotics

Exploring the efficient and sustainable photocatalysts is the key pot for the improvement of photocatalytic efficiency. In this work, a series of Bi5O7I/BiOIO3 composite materials were successfully prepared via a mild hydrothermal method to make layered BiOIO3 nanosheets uniformly grown in-situ on the smooth surface of Bi5O7I microrods. The electronic channel at the interface constructed by the in-situ growth could drastically shorten the distance of electron transmission to accelerate the electron transfer. The formation of Bi5O7I/BiOIO3 heterojunction was determined via the characterization of the composition and photochemical analysis. Benefited from this structure, the Bi5O7I/BiOIO3 with the mass ratio of 1:1 exhibited over 90% efficiency in degradation of 4 different antibiotics after irradiation for 120 min. After that, 5 cycles proved that Bi5O7I/BiOIO3 has excellent stability and reusability, which can guarantee the application in the practical process. Finally, the electron migration path and photocatalytic mechanism of the catalyst are inferred base on the capture experiment and ESR test, which proposed that h+ and ·O2- were the primary active species in the photocatalytic process and confirmed the formation of Z-type heterojunctions between Bi5O7I and BiOIO3. The heterostructure with well-matched band structure enhances the separation and migration of photogenerated charges, which contributes to improve the photocatalytic activity. The design of novel photocatalyst with high efficiency and low-toxicity provides a new approach to achieve full utilization of solar energy and efficient environmental purification.