光电阴极
六价铬
光电流
检出限
材料科学
电化学
铬
分析化学(期刊)
光电子学
电极
化学
物理
冶金
物理化学
电子
量子力学
色谱法
作者
Wenxiang Lu,Lu Ma,Shengchen Ke,Rouxi Zhang,Wen Zhu,Linling Qin,Shaolong Wu
出处
期刊:Nanomaterials
[MDPI AG]
日期:2023-04-26
卷期号:13 (9): 1479-1479
被引量:1
摘要
Photoelectrochemical (PEC) sensors show great potential for the detection of heavy metal ions because of their low background noise, high sensitivity, and ease of integration. However, the detection limit is relatively high for hexavalent chromium (Cr(VI)) monitoring in addition to the requirement of an external bias. Herein, a CuO film is readily synthesized as the photoactive material via reactive sputtering and thermal annealing in the construction of a PEC sensing photocathode for Cr(VI) monitoring. A different mechanism (i.e., Signal-Weakening PEC sensing) is confirmed by examining the electrochemical impedance and photocurrent response of different CuO film photoelectrodes prepared with the same conditions in contact with various solutions containing concentration-varying Cr(VI) for different durations. The detection of Cr(VI) is successfully achieved with the Signal-Weakening PEC response; a drop of photocathode signal with an increasing Cr(VI) concentration from the steric hindrance effect of the in situ formed Cr(OH)3 precipitates. The photocurrent of the optimized CuO film photocathode linearly declines as the concentration of Cr(VI) increases from 0.08 to 20 µM, with a detection limit down to 2.8 nM (Signal/Noise = 3) and a fitted sensitivity of 4.22 µA·μM-1. Moreover, this proposed sensing route shows operation simplicity, satisfactory selectivity, and reproducibility.
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