Reliable and selective lead-ion sensor of sulfur-doped graphitic carbon nitride nanoflakes.

• S-g-C 3 N 4 nanoflake with a large specific surface area of 189.26 m2 g−1 was prepared. • The proposed S-g-C 3 N 4 /GCE sensor exhibited excellent performance for Pb2+ detection. • The high selectivity can be attributed to a strong interaction via S Pb bond. • The strong interaction between S-g-C 3 N 4 interface and Pb2+ was confirmed by DFT. An optimum large specific surface area of sulfur-doped graphitic carbon nitride nanoflakes modified glassy carbon electrode (S-g-C 3 N 4 /GCE) is reported with promising lead ion (Pb2+) detection capability. This sensor was designed and fabricated using thermal polycondesation reaction. In terms of high selectivity Pb2+ performance, we noted that the sensor exhibited appreciable detection limit of 3.0 × 10−9 mol L−1 (S/N = 3) within the ionic specimen concentration range of 7.5 × 10−8 ~ 2.5 × 10−6 mol L−1 and 2.5 × 10−6 ~ 1 × 10−3 mol L−1. Corroborated by DFT calculations, we propose that the strong interaction of S-g-C 3 N 4 interface and Pb2+ plays an important role to generate the aforementioned sensing characteristics. In practice, we conceived high detection of Pb2+ ions that reside in lake-water and mineral samples in which percentage recovery of 88–103 can be obtained under high repetition rate. Thus, S-g-C 3 N 4 /GCE can be considered as sensitive and selective electrochemical sensor for a reliable detecting heavy metal ions in domestic sewage and industrial wastewater. [ABSTRACT FROM AUTHOR]