Highly selective and rapid non-enzymatic glucose sensing at ultrathin layered Nb doped C3N4 for extended linearity range

摘要

Ultrathin layered graphitic carbon nitride (g-C3N4) doped with niobium (Nb) metal has been prepared from urea by pyrolysis method and applied for direct glucose sensing in human blood. Two different oxidation peaks during both forward and reverse potential scanning were observed, similar to metal electrodes, indicating the metallic behavior of the g-Nb-C3N4. The oxidation peak appeared at 0.39 V indicates the oxidation of glucose to gluconolactone, which gets further oxidized to CO2 and H2O during reverse scan indicated by the appearance of very intense reverse peak. The sensor gave an extended wide dynamic range from 0.5 mM to 200 mM with an excellent sensitivity of 1.62 mu A mM(-1) cm(-2). Micahelis-Menten kinetic constant K-M of 181 mM observed is 100 times higher than the un-doped g-C3N4. The developed sensor electrode is tested for glucose sensing in the human blood samples and showed good signal recovery for 4 times reuse.