Photoelectrocatalytic degradation of sulfosalicylic acid and its electrochemical impedance spectroscopy investigation

A three-electrode system composed of TiO2/Ni as the working electrode, poro us nickel as the counter electrode, and saturated calomel electrode (SCE) a s the reference electrode was used for the photoelectrocatalytic degradatio n of organic compounds. The photoelectrocatalytic degradation of sulfosalic ylic acid (SSal) under anodic bias potential was investigated. It is shown that SSal can be degraded effectively as the external potential is increase d up to 700 mV (vs SCE). The characteristics by electrochemical impedance s pectroscopy (EIS) of the photoelectrocatalytic degradation of sulfosalicyli c acid (SSal) was also investigated. It is shown from the EIS that the phot oelectrocatalytic degradation appears to be a simple reaction on the electr ode surf-ace, suggesting that only one step of charge transfer is involved in the electrode process. The value of the resistance of charge transfer fo r the photoelectrocatalytic reaction of SSal manifests itself not only in t he reaction rate, but also in the separation efficiency of the photogenerat ed electron-hale pairs. The separation efficiency of the electron-hole pair s under N-2 atmosphere is higher than that under Oz atmosphere.