CdS/CdO core/shell nanorod photoelectrochemical electrodes were prepared and the working mechanism of n-/n-type Z-scheme band structures is proposed based upon the shell thickness variation. A mild solution chemistry enabled the vertical growth of CdS nanorods on the low-cost conductive glass substrates. The thermal decomposition of Cd(NO₃)₂·4H₂O coated on the CdS nanorod surface successfully introduced CdS/CdO core/shell nanorod electrodes. The formation of CdO shell on CdS nanorods led to the improved photoelectrochemical performance through constructing the n-/n-type Z-scheme band structure. From the Mott-Schottky and the open-circuit potential analyses, the variation in the flat band potentials were monitored to understand the change in the photovoltage of the n-/n-type Z-scheme nanorod electrodes regarding the CdO shell thickness. The core/shell nanorod electrodes having the shell thickness equal to or smaller than the space charge region width exhibited higher photovoltages than those of others. This could be the outcome of the effective charge separation coming from the absence of the bulk region in which the electron transport is disturbed by boundaries. Finally, the optimum CdO shell thickness of CdS/CdO electrodes was determined to be ~2nm and their corresponding photocurrent density was measured to be ~4.35mA/cm², which is a ~22% increased value compared to that of bare CdS nanorod electrodes.

中文翻译：

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Z型CdS / CdO纳米棒在FTO衬底上的形成：壳厚度对平坦带电势的影响

制备了CdS / CdO核/壳纳米棒光电化学电极，并基于壳厚度的变化，提出了n- / n型Z型能带结构的工作机理。温和的溶液化学作用使CdS纳米棒在低成本的导电玻璃基板上垂直生长。Cd（NO ₃）₂ ·4H ₂的热分解涂覆在CdS纳米棒表面的O成功引入了CdS / CdO核/壳纳米棒电极。CdS纳米棒上CdO壳的形成通过构造n- / n型Z-方案带结构而提高了光电化学性能。通过Mott-Schottky和开路电势分析，可以监测平带电势的变化，以了解n- / n型Z方案纳米棒电极的光电压与CdO壳厚度有关的变化。壳厚度等于或小于空间电荷区域宽度的核/壳纳米棒电极表现出比其他电极更高的光电压。这可能是有效电荷分离的结果，因为没有电子传输受边界干扰的主体区域。最后，^{如图2所示}，与裸CdS纳米棒电极相比，该值增加了〜22％。