Kadhim M J, Mahdi M A, Hassan J J, Al-Asadi Ahmed S
Department of Physics, College of Science, University of Basrah, Basrah, Iraq.
Department of Physics, College of Education for Pure Science, University of Basrah, Iraq.
Nanotechnology. 2021 May 7;32(19):195706. doi: 10.1088/1361-6528/abe3b3.
Zinc oxide (ZnO) nanorod thin films were prepared by CBD onto glass and FTO/glass substrates. Silver (Ag) nanoparticles were synthesized on the surface of the prepared ZnO nanorod thin films using electrochemical methods. The scanning electron microscopy images of the Ag/ZnO/glass core/shell nanostructure confirmed that the average particles size is 20 nm while it was 41 nm for Ag NPs that synthesized onto ZnO/FTO NRs. The photocatalytic activity of the prepared Ag/ZnO core/shell nanostructure was studied by analyzing the degradation of methylene blue (MB) dye under visible light. Various pH values (6 and 10) and exposure time (30-240) min were controlled to investigate the photocatalytic activity of as-prepared Ag/ZnO core/shell nanostructure and that annealed at 200 °C and 300 °C for 1 h. It was observed that when the pH was 6, the degradation rate increased with the annealing temperature and irradiation time reaching 51% at the annealing temperature of 300 °C and exposure time of 240 min. In other hands, when the pH was 10, and the sample was annealed at 200 °C, it showed a good degradation rate of 100% at the irradiation time of 90 min. By contrast, the sample annealed at 300 °C required 180 min to degrade the MB dye completely. The photoelectrochemical cell measurement based on photocurrent density revealed a slight response to light. Cycle voltammetry (CV) measurement was conducted, and the CV curves of the Ag/ZnO core/shell electrodes indicated nonfaradaic and pseudocapacitance behavior. The electrodes showed nearly rectangular CV curves, which indicated the dominance of the nonfaradaic capacitance behavior. The specific capacitance of the electrodes remained at approximately 99%. Mott-Schottky analysis revealed that the semiconductor was an n-type with dependence on flat band potential V deviation in the negative direction.
通过化学浴沉积法在玻璃和FTO/玻璃基板上制备了氧化锌（ZnO）纳米棒薄膜。采用电化学方法在制备的ZnO纳米棒薄膜表面合成了银（Ag）纳米颗粒。Ag/ZnO/玻璃核壳纳米结构的扫描电子显微镜图像证实，平均粒径为20nm，而在ZnO/FTO纳米棒上合成的Ag NPs的平均粒径为41nm。通过分析亚甲基蓝（MB）染料在可见光下的降解情况，研究了制备的Ag/ZnO核壳纳米结构的光催化活性。控制各种pH值（6和10）和暴露时间（30 - 240）分钟，以研究制备的Ag/ZnO核壳纳米结构以及在200℃和300℃退火1小时后的光催化活性。观察到，当pH为6时，降解率随退火温度和辐照时间增加，在退火温度为300℃和暴露时间为240分钟时达到51%。另一方面，当pH为10且样品在200℃退火时，在辐照时间为90分钟时显示出100%的良好降解率。相比之下，在300℃退火的样品需要180分钟才能完全降解MB染料。基于光电流密度的光电化学电池测量显示对光有轻微响应。进行了循环伏安法（CV）测量，Ag/ZnO核壳电极的CV曲线表明存在非法拉第和赝电容行为。电极显示出近乎矩形的CV曲线，这表明非法拉第电容行为占主导。电极的比电容保持在约99%。莫特 - 肖特基分析表明，该半导体为n型，其平带电位V在负方向上存在偏差。
