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Piezo-potential facilitated photocatalytic activation of persulfate over α-Fe2O3 and mechanism insight
Applied Surface Science ( IF 6.3 ) Pub Date : 2020-11-19 , DOI: 10.1016/j.apsusc.2020.148488
Qiujin Shi , Shuai Yue , Zhanqi Liu , Mingzheng Xie , Weihua Han

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.



中文翻译:

压电势促进过硫酸的光催化活化过的α-Fe 2 ö 3和机构洞察

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。

更新日期:2020-11-19
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