A facile photoelectrochemical sensor for high sensitive ROS and AA detection based on graphitic carbon nitride nanosheets

Photoactive material is one of the main challenges for fabrication of sensitive and selective photoelectrochemical (PEC) sensor. Herein, a facile PEC sensor is constructed using graphitic carbon nitride nanosheets (g-C3N4 NSs) coated on the surface of ITO electrode, where electron donor properties of potassium ferrocyanide and ascorbic acid is utilized for the tracing of hydrogen peroxide (H2O2), hypochlorite (ClO-), and ascorbic acid (AA). Our designed PEC sensor exhibits a good linear range to H2O2 concentrations from 12.5 to 875 µM in pH = 7.4 and 2.5-400 µM in pH = 10, while that for AA is in the range from 0.25 to 100 µM in pH = 7.4, and with the same pH for ClO- concentrations in the range from 0.5 to 19 × 10−3% (V/V) in a bleach sample. Owing to the good responses towards the traces of H2O2, AA, and ClO-, our designed system may be used as H2O2, ClO-, and AA sensor for outdoor applications with high specificity, long-time stability and good reproducibility.