Electrochemical process of early-stage corrosion detection based on N-doped carbon dots with superior Fe3+ responsiveness

Iron corrosion is a subject of great technological importance and extensive public concern. However, the highly efficient detection of iron corrosion at early stage is still a challenging task. Herein, bright fluorescent carbon dots (CDs) with superior response to Fe 3+ were prepared by simple solvothermal process based on citric acid and ammonia. The obtained CDs are able to rapidly, sensitively and selectively respond to Fe 3+ . The quantitative analysis showed that the CDs exhibited a linear response to Fe 3+ in the range of 10 to 300 µM, with a detection limit of 0.9 μM. And the fluorescence quenching of CDs was obvious enough to be detected by the naked eyes. Such promising responsiveness of CDs offers a great opportunity for real-time and visual detection of Fe 3+ during electrochemical corrosion process. In addition, due to the excellent stability and solubility of CDs, patterned papers and hydrogels have been fabricated utilizing cellulose and PVA as matrices. The as-prepared biocompatible, environmental-friendly and disposable CDs based fluorescent materials were successfully used for detecting the degree of iron corrosion. This could provide a simple and visual strategy for monitoring the safety of structural metal materials.