The high toxicity and bioaccumulation of mercury (Hg²⁺) ions have raised concerns about the dynamic changes of trace Hg²⁺ ions in the environment. Although conventional Hg²⁺ ion detection techniques provide highly sensitive and specific results, complex sample pre-treatment damages the native aquatic environment for Hg²⁺ ions resulting in detection inaccuracy, and the need for a stable external power supply limits real-time detection of Hg²⁺ ions in the field where power is scarce. The triboelectric nanogenerator (TENG) with no pre-treatment and self-powering provide a sustainable solution for Hg²⁺ ion detection. In this work, a thiourea-enhanced bifunctional covalent organic framework triboelectric nanosensor (TENS) was proposed. The thiourea moiety not only enhances the electrical output performance of the COF-based TENG to improve the detection sensitivity, but also serves as a specific binding site to recognize Hg²⁺ ions. The prepared COF-based TENS had the advantages of low detection limit (31.6 pM), wide linear range (10^-10 M to 10^-4 M), high selectivity, reusability and stability. And it was suitable for the detection of Hg²⁺ ion concentration in real samples (drinking water, tap water, river water and lake water). The developed detection system was connected in series with LEDs without external power supply to realize LED-indicated Hg²⁺ ion detection in water samples. This study provided a novel implementation example of a COF-based TENS, which also provided a more convenient and sustainable idea for the detection of heavy metal pollution.

中文翻译：

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硫脲增强的双功能共价有机框架摩擦纳米传感器，用于 Hg2+ 离子的高效检测和可视化

汞 （Hg ²⁺ ） 离子的高毒性和生物蓄积性引起了人们对环境中痕量 Hg ²⁺ 离子动态变化的担忧。尽管传统的汞 ²⁺ 离子检测技术可提供高灵敏度和特异性的结果，但复杂的样品预处理会破坏汞 ²⁺ 离子的天然水生环境，导致检测不准确，并且需要稳定的外部电源限制了在电力稀缺的现场实时检测汞 ²⁺ 离子。摩擦纳米发电机 （TENG） 无需预处理，可自供电，为汞 ²⁺ 离子检测提供可持续的解决方案。在这项工作中，提出了一种硫脲增强的双功能共价有机框架摩擦电纳米传感器 （TENS）。硫脲基团不仅增强了基于 COF 的 TENG 的电输出性能，提高了检测灵敏度，而且还可以作为识别 Hg ²⁺ 离子的特异性结合位点。制备的基于 COF 的 TENS 具有检出限低 （31.6 pM）、线性范围宽 （10 ^-10  M 至 10 ^-4  M）、选择性高、可重复使用性和稳定性等优点。适用于实际样品（饮用水、自来水、河水和湖水）中 Hg ²⁺ 离子浓度的检测。开发的检测系统与 LED 串联，无需外部电源，实现水样中 LED 指示的 Hg ²⁺ 离子检测。本研究提供了一个基于 COF 的 TENS 的新实施实例，也为重金属污染的检测提供了更方便、更可持续的思路。