An efficient and cost-effective nanocomposite, zinc oxide-polypyrrole (ZnO-PPy) was synthesized via a simple ultrasonic technique. The as-prepared ZnO-PPy nanocomposite was characterized and confirmed by various analytical techniques such as XRD, FT-IR, UV-DRS, SEM and elemental mapping analysis. The ZnO-PPy nanocomposite has been shown to be highly efficient reduction of toxic Cr⁶⁺ to Cr³⁺ under visible light compared to pure ZnO. The better photocatalytic activity is due to the visible light active PPy covered on the surface of ZnO, which can accelerate and separate the electron and hole pairs and reduce the recombination. In the ZnO-PPy nanocomposite system, the photocatalytic reduction rate constant and percentage were observed at k = 0.2572 min⁻¹ and 99.2 % and the catalysts shows higher efficiency even after four cycles. Interestingly, the effect of foreign ions (cations and anions) and reaction pH were optimized and discussed. Meanwhile, the ZnO-PPy nanocomposite charge transfer mechanism were investigated through photocurrent and impedance analysis. This work demonstrates that a simple ultrasonic method efficiently utilized for the preparation of nanocomposite and its applications.

通过一种简单的超声技术合成了一种高效且具有成本效益的纳米复合材料氧化锌-聚吡咯（ZnO-PPy）。通过各种分析技术（如XRD，FT-IR，UV-DRS，SEM和元素图谱分析）对制备的ZnO-PPy纳米复合材料进行了表征和确认。与纯ZnO相比，ZnO-PPy纳米复合材料在可见光下能有效地将有毒Cr ⁶⁺还原为Cr ³⁺。更好的光催化活性是由于覆盖在ZnO表面的可见光活性PPy可以加速和分离电子和空穴对并减少重组。在ZnO-PPy纳米复合材料体系中，在k = 0.2572 min ^-1处观察到光催化还原速率常数和百分数和99.2％，催化剂甚至在四个循环后仍显示较高的效率。有趣的是，对外来离子（阳离子和阴离子）和反应pH的影响进行了优化和讨论。同时，通过光电流和阻抗分析研究了ZnO-PPy纳米复合材料的电荷转移机理。这项工作表明，一种简单的超声方法可有效地用于制备纳米复合材料及其应用。