Colorimetric sensor nanoarchitectonics for trace Pb2+ ions detection by porous fungus-like CoS nanozyme

The heavy metal lead (Pb) holds significant importance in the manufacturing industry due to its extensive range of applications. However, its high toxicity poses a serious risk to both environment and human health. Consequently, on-site portable analysis methods have been developed to detect Pb2+, which is advantageous for obtaining timely information regarding environmental pollution. In this study, a fungal-like porous CoS (FP CoS) was discovered to selectively recognize, adsorb, and detect Pb2+. FP CoS exhibited rapid kinetics (reducing from 8.56 mg∙L–1 to 69 µg∙L–1 within 30 min) as well as exceptional adsorption capacity of 88.14 mg∙g−1 for Pb2+. Benefiting from the selective enrichment of Pb2+, the peroxidase-like activity of FP CoS nanoenzyme was further enhanced, enabling colorimetric detection of Pb2+ with a detection limit of 14 ng∙L–1, surpassing numerous reported materials. When applied to environmental samples spiked with 0–100 μg∙L–1 Pb2+, the combination of FP CoS nanosensor and a portable RGB color sensor yielded an impressive recovery percentage of 112 %. Based on these results, the FP CoS nanosensor not only provides a rapid and visually discernible colorimetric approach for trace and ultra-trace Pb2+ but also serves as a sensitive sensor for detecting Pb2+ in various scenarios.