Photoelectrochemical quantification of hydrogen peroxide with g-C3N4/BiFeO3

Excessive levels of certain active substances in the water will cause a series of environmental problems and affect human health, among which, hydrogen peroxide (H2O2) is a typical one. Therefore, it is of great significance to determine the content of H2O2 in industrial wastewater. However, there are great challenges to monitoring H2O2 due to the high redox overpotential of the traditional electrode and the poor measurement sensitivity. Herein, a g-C3N4/BiFeO3 photoelectrochemical (PEC) sensor is prepared to effectively stimulate the reduction of H2O2. Under visible light irradiation, the H2O2 detection limit of the g-C3N4/BiFeO3 PEC sensor reaches 2.015 μM, which is 4.7 times that of traditional electrochemical method. Through UV-vis and Mott-Schottky characterizations, the mechanism concerning enhancement of sensor performance was studied. The results show that the band gap and energy band difference of g-C3N4 and BiFeO3 can effectively avoid the recombination of electrons and holes. The proposed photoelectrochemical sensor obtains a calibration curve range for H2O2 from 2.99 μM to 0.03 M with high sensitivity and good selectivity. In addition, the sensor can detect H2O2 in actual textile wastewater samples, providing a promosing method for the detection of active substances in the environment, and has broad prospects in environmental monitoring.