Amperometric Highly Sensitive Phosphate Ion Sensor Based on the Electrochemically Modified Ni Electrode

We present a study of high-performance electrochemical phosphate sensors, which are exquisitely designed and easy to operate. We innovatively utilized the insolubility of nickel phosphate and developed a new type of sensor through electrochemical methods. The experiment first used cyclic voltammetry to determine −0.4 V as the optimal electrochemical modification potential and used constant potential electrodeposition technology to form a nickel oxide layer on the surface of the nickel electrode, which serves as the active layer in response to phosphate ions. The changes in the surface structure and chemical composition of the electrode before and after modification were thoroughly characterized by scanning electron microscopy and energy scattering spectroscopy analysis. The performance evaluation of the sensor shows that the modified nickel electrode has excellent responsiveness to phosphate ions in the concentration range of 10–7 to 10–10 mol/L, with a detection lower limit of 10–10 mol/L. As the concentration decreases, a shoulder peak appears at ∼0.63 V and the current change shows a regular increase. Compared with traditional detection methods, this sensor exhibits higher stability and practicality and is suitable for the rapid identification of phosphates in real samples. In summary, this study successfully developed a fast, sensitive, and wide response range current type electrochemical phosphate sensor, which has broad application prospects in environmental monitoring, water quality analysis, and biomedical fields.