La₂Zr₂O₇/Bi₂Sn₂O₇ heterostructure for photocatalytic degradation of tetracycline with the aid of hydrogen peroxide under visible light irradiation

Photocatalytic degradation technology serves as an environmental-friendly mean for the removal of organic pollutants in wastewater. La₂Zr₂O₇/Bi₂Sn₂O₇ (LZO/BSO, cata) composite photocatalysts have been successfully fabricated through the in-situ growth approach. The phase composition, microstructure and optical property of the materials have been examined. The results indicate that the "cata + H₂O₂ + vis" hybrid system exhibites the optimal photocatalytic performance in the photocatalytic degradation process of tetracycline (TC). Under this optimal condition, the degradation rate of TC reaches 90% after 70 min of visible light irradiation. And the apparent rate constant of the "cata + H₂O₂ + vis" system is obviously higher than those of "H₂O₂ + vis" and "cata + H₂O₂″ systems. The main active species have been confirmed to include ·O₂⁻, h⁺ and ·OH in the degradation process of TC by the "cata + H₂O₂ + vis” system. The enhanced photocatalytic activity is achieved by improving the separation efficiency of charge carriers in heterojunction structure and producing more active species with the assistance of hydrogen peroxide. The effective Z-scheme-type heterojunction photocatalyst proposed in this study has the potential to be applied in the degradation of organic pollutants in wastewater.