Superoxide radical (O₂·^-) is the main active species to generate sulfate radicals during the persulfate (PS) activation assisted by photocatalysis. As a widely-used photocatalyst, α-Fe₂O₃ usually exhibits negligible activity for O₂·^- generation attributed to the low conduction band (CB) and photogenerated carrier mobility. In this work, we try to overcome the drawbacks by means of negative piezo-potential generated from strained ZnO nanorod. ZnO nanorod array is prepared by a hydrothermal method, and α-Fe₂O₃ is attached on it through a sol-gel process. The as-prepared showed obviously enhanced visible-light activity for PS activation under the impact of water flow, and the PS activation efficiency could reach 70% in 1 h. The activity is rarely decreased in 5 cycles and no Fe ions detected in the solution, indicating the nanocomposite possesses high stability. The enhanced activity is largely related to the additional negative piezo-potential generated in the top of ZnO nanorod. The resulted negative electric field could evaluate the CB of α-Fe₂O₃, thereby improving photogenerated charge reduction activity. Moreover, the field facilitates the opposite transports of photoelectrons and holes, due which the separation rate is enhanced. Consequently, the generation of O₂·^- radicals which act as the dominant species in PS activation is promoted.

超氧自由基（O ₂ · ^-）是在光催化辅助的过硫酸盐（PS）活化过程中产生硫酸根自由基的主要活性物质。作为一种广泛使用的光催化剂，的α-Fe ₂ ö ₃通常表现出可以忽略不计的活性代表O ₂ · ^-生成归因于低导带（CB）和光生载流子迁移率。在这项工作中，我们尝试通过应变的ZnO纳米棒产生的负压电势来克服这些缺点。ZnO纳米棒阵列由水热法制备，和的α-Fe ₂ ö ₃通过溶胶-凝胶工艺附着在其上。所制备的PS在水流的影响下可见光活化明显增强，在1 h内PS活化效率可达70％。活性在5个循环中很少降低，在溶液中未检测到Fe离子，表明该纳米复合材料具有很高的稳定性。增强的活性很大程度上与在ZnO纳米棒顶部产生的附加负压电势有关。将所得到的负电场可以评估的α-Fe的CB ₂ Ó ₃，从而提高了光生电荷减少的活性。此外，该场促进了光电子和空穴的相反传输，因此提高了分离速率。因此，O ₂的产生· ^-促进了在PS活化中起主导作用的自由基。