AbstractPhotocathodic methods in photoelectrochemical (PEC) analysis are based on the use of functional photocathodes. Heterojunction cathodes consisting of different kinds of semiconductors are being considered as favorite schemes when compared to the single-component ones. A semiconductor heterojunction between CuBi2O4 (CBO) and other semiconductors has not been exploited in PEC assays so far. Herein, CBO nanospheres were initially electrochemically deposited on a fluorine-doped tin oxide (FTO) conductive glass and then coupled to chemically deposited AgI nanoparticles to obtain an electrode of type AgI/CBO/FTO. It was applied as a cathode in the PEC detection of L-cysteine as a model analyte. The sensor can selectively detect L-cysteine, and it is assumed that this is due to the selective interaction between the L-cysteine and both copper and silver via the formation of Cu-S and Ag-S bonds. The photocurrent of the electrode increases linearly with the logarithm of the cysteine concentration in the range from 0.1 and 50 μM, and the detection limit is 0.1 μM. Graphical abstractSchematic presentation of the preparation of an AgI/CuBi2O4 (AgI/CBO) heterojunction on a fluorine-doped tin oxide (FTO) electrode and its application to the cathodic photoelectrochemical detection of L-cysteine.

中文翻译：

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在氟掺杂氧化锡电极上制备 AgI/CuBi2O4 异质结，用于阴极光电化学分析：在 L-半胱氨酸检测中的应用

摘要 光电化学 (PEC) 分析中的光电阴极方法基于功能光电阴极的使用。与单组分阴极相比，由不同种类的半导体组成的异质结阴极被认为是最受欢迎的方案。迄今为止，尚未在 PEC 分析中利用 CuBi2O4 (CBO) 和其他半导体之间的半导体异质结。在此，CBO 纳米球最初是电化学沉积在掺氟氧化锡 (FTO) 导电玻璃上，然后与化学沉积的 AgI 纳米颗粒耦合以获得 AgI/CBO/FTO 类型的电极。它在 L-半胱氨酸作为模型分析物的 PEC 检测中用作阴极。该传感器可以选择性地检测L-半胱氨酸，并且假设这是由于 L-半胱氨酸与铜和银之间通过形成 Cu-S 和 Ag-S 键的选择性相互作用。电极的光电流在0.1~50 μM范围内随半胱氨酸浓度的对数线性增加，检测限为0.1 μM。图形摘要在掺氟氧化锡 (FTO) 电极上制备 AgI/CuBi2O4 (AgI/CBO) 异质结及其在 L-半胱氨酸的阴极光电化学检测中的应用的示意图。