<p>The simultaneous purification of multiple mixed pollutants holds significant practical value in addressing the growing environmental challenges of today. In this work, UiO-66-NH₂(Hf) octahedrons were successfully synthesized and grown on BiOBr nanosheets to form a novel heterojunction, BiOBr/UiO-66-NH₂(Hf). This BiOBr/UiO-66-NH₂(Hf) heterojunction exhibits enhanced photocatalytic degradation and reduction activities. Specifically, the degradation rate of tetracycline hydrochloride (TC) reached 84.8%, while the reduction efficiency of Cr(VI) approached 100%, demonstrating the material’s effectiveness in simultaneously purifying mixed pollutants. Furthermore, when ultrasonic force was applied, the degradation rate of TC increased from 57.1% to 84.8%, and the reduction rate of Cr(VI) improved from 73.5% to 100%. These results highlight the material’s excellent piezoelectric properties, which were confirmed through density functional theory calculations and piezoresponse force microscopy. This work introduces a novel piezoelectric-coupled photocatalyst that offers a new strategy for the efficient purification of mixed pollutants. Additionally, it demonstrates that TC can promote the reduction of Cr(VI) in place of hole quenchers, while simultaneously undergoing degradation. This approach reveals promising prospects for the effective removal of mixed pollutants.</p>