Hydrogen sulfide (H₂S), as both an endogenously gaseous signaling compound and an environmentally hazardous substance, has shown great relevance to human health and ecosystem safety. However, a reliable sensing platform for the facile detection of trace H₂S is still a challenge to be addressed. Herein, a AgI-TiO₂ nanorods array electrode was fabricated through a hydrothermal method followed by ultrasonic impregnation treatment to construct an ultrasensitive photoelectrochemical H₂S sensor. The decorated AgI could not only play a significant role in the enhancement of visible light absorbance as a narrow bandgap sensitizer but also contribute to the specific affinity towards sulfide as the recognition unit. In the presence of sulfide, multiple heterojunctions were established in situ due to I⁻-to-S²⁻ exchange at the AgI sites, proportionately increasing the photocurrent response of the functionalized PEC electrodes. The designed photoelectrochemical (PEC) sensing platform could achieve the quantitative determination of sulfide in a wide range of 1 ∼ 1000 nM with an effective detection limit of 1.25 nM. Additionally, the detection performances for practical H₂S-containing waste gas and the biological environment were also evaluated. This work could broaden a new vision of the delicate design of interfaces for ultrasensitive environmental analysis.

硫化氢（H ₂ S）既是一种内源性气态信号化合物，又是一种对环境有害的物质，已显示出对人类健康和生态系统安全的重要意义。然而，用于痕量H ₂ S的简便检测的可靠传感平台仍然是一个有待解决的挑战。本文采用水热法制备AgI-TiO ₂纳米棒阵列电极，然后进行超声浸渍处理，制备出超灵敏的光电化学H _2。S传感器。装饰的AgI不仅可以作为窄带隙敏化剂在增强可见光吸收方面起重要作用，而且还可以促进对硫化物作为识别单元的特异性亲和力。在硫化物的存在下，多个异质结建立原位由于我^- -to-S ^2-交换在的AgI位点，按比例增加了官能PEC电极的光电流响应。设计的光电化学（PEC）传感平台可以在1到1000 nM的宽范围内实现硫化物的定量测定，有效检出限为1.25 nM。此外，实际H ₂的检测性能还评估了含S的废气和生物环境。这项工作可以为超灵敏环境分析的接口的精细设计开辟新的视野。