ZnS-assembled CdIn2S4 Z-type heterojunction as a photoelectrochemical sensor for ultra-trace detection of m-nitrophenol in environmental water samples

Characterized by high toxicity and difficult degradation, m-nitrophenol (3-NP) is an environmental pollutant that endangers the environment and biological systems. Therefore, the development of analytical techniques for the detection of low concentrations of 3-NP is critical for the environment and human health. In this work, spherical CdIn2S4 and tiny ZnS particles were prepared by a hydrothermal method, and the Z-type ZnS/CdIn2S4 heterojunction material was obtained by ultrasonically assembling ZnS onto CdIn2S4. The Z-type ZnS/CdIn2S4 heterojunction possesses a better photocurrent response and a good electron transport capacity, and it can efficiently separate the photogenerated electron-hole pairs. Therefore, a photoelectrochemical sensor for accurate detection of 3-NP in water was constructed based on the Z-type ZnS/CdIn2S4 heterostructure. The sensor has a detection range from 5 × 10−12 M to 1 × 10−8 M and an extremely low limit of detection (1.28 ×10−12 M), which is rare among other sensors. Meanwhile, the sensor showed excellent performance in real samples, indicating that it can effectively monitor 3-NP in real water samples. The validation of the sensor using UV–visible spectra also yielded satisfactory results.