School of Environment, Harbin Institute of Technology, Harbin, Heilongjiang 150090, PR China; Institute of Medicine and Materials Applied Technologies, College of Chemistry and Chemical Engineering, Qufu Normal University, Qufu, Shandong 273165, PR China.
Institute of Medicine and Materials Applied Technologies, College of Chemistry and Chemical Engineering, Qufu Normal University, Qufu, Shandong 273165, PR China.
J Hazard Mater. 2020 Apr 5;387:121715. doi: 10.1016/j.jhazmat.2019.121715. Epub 2019 Nov 19.
A visible-light-driven photoelectrochemical (PEC) sensor has been developed for the "signal-on" analysis of Hg by the synergetic combination of low-bandgap AgS and wide-bandgap ZnS quantum dots (QDs). AgS QDs were synthesized with bead-chain-like structure by the self-assembly route and further covalently bound with ZnS QDs to be coated onto the indium tin oxide (ITO) electrodes. It was discovered that the ZnS@AgS-modified electrodes could display the visible-light-driven PEC behavior, of which AgS and ZnS QDs could act as the PEC sensitizer and Hg-recognition probe, respectively. More importantly, the photocurrent responses of the developed electrodes could be specifically turned on in the presence of Hg under the visible-light irradiation, presumably due to that Hg might conduct a Zn-to-Hg exchange on ZnS QDs to trigger the formation of HgS/ZnS@AgS heterojunction towards the enhanced electron-hole separation. The as-prepared PEC sensor could facilitate the detection of Hg with concentrations ranging from 0.010-1000 nM, with a detection limit of about 1.0 pM. Besides, the feasibility of practical applications of the developed PEC analysis strategy was verified by probing Hg in environmental water samples. Such a visible-light-driven PEC detection platform with the unique "turn-on" signal output may promise for the extensive applications for Hg evaluation.
一种可见光驱动的光电化学（PEC）传感器已经被开发出来，用于通过低带隙 AgS 和宽带隙 ZnS 量子点（QD）的协同组合对 Hg 进行“信号开启”分析。AgS QD 通过自组装路线合成具有珠链状结构，并进一步与 ZnS QD 共价结合，以涂覆在铟锡氧化物（ITO）电极上。研究发现，ZnS@AgS 修饰电极可以显示可见光驱动的 PEC 行为，其中 AgS 和 ZnS QD 可以分别作为 PEC 敏化剂和 Hg 识别探针。更重要的是，在可见光照射下，开发的电极的光电流响应可以在 Hg 的存在下特异性地开启，这可能是因为 Hg 可能在 ZnS QD 上进行 Zn 到 Hg 的交换，引发 HgS/ZnS@AgS 异质结的形成，从而增强电子-空穴分离。所制备的 PEC 传感器可以促进对浓度范围为 0.010-1000 nM 的 Hg 的检测，检测限约为 1.0 pM。此外，通过探测环境水样中的 Hg，验证了所开发的 PEC 分析策略的实际应用可行性。这种具有独特“开启”信号输出的可见光驱动的 PEC 检测平台可能有望广泛应用于 Hg 评估。
