Hierarchical porous loofah-like carbon with sulfhydryl functionality for electrochemical detection of trace mercury in water.

Mercury is a common contaminant found in natural waters, which is highly toxic to human health. Thus, the facile and reliable monitoring of mercury in waters is of great significance. In this study, we fabricated a novel loofah-like hierarchical porous carbon with sulfhydryl functionality (S-LHC), and applied it as an ultrasensitive sensor for the electrochemical detection of mercury in water. The S-LHC was prepared through the direct pyrolysis of a triazole-rich metal-organic framework (MOF), followed by chemical modification using thioglycolic acid. The highly conductive N-doped carbon framework of S-LHC facilitated the electron transfer in mercury electrochemical sensing. Meanwhile, the open hierarchical pore structure and abundant sulfhydryl groups allowed the fast diffusion and effective enrichment of mercury ions. Consequently, the S-LHC sensor exhibited an exceptionally high sensitivity for mercury ions, with the mercury detection limit (0.36 nM) orders of magnitude lower than the regulated values in drinking water (typically 10∼30 nM). The constructed sensor also afforded good anti-interference ability and excellent stability for long-term detection of mercury in a variety of complex real water samples. The present study provides not only a facile method for mercury detection, but also a new idea for the construction of highly sensitive electrochemical sensors.