Enhanced Activity and Stability of PbO2 Electrodes by Modification with Octadecyl Phosphonic Acid

A novel Ti/Sn-SbOx/PbO2-ODP electrode was constructed using a beta-PbO2 layer modified with octadecyl phosphonic acid (ODP) through a co-electrodeposition method. Scanning electron microscopy with an energy dispersive spectrometer, X-ray diffraction and contact angle goniometry confirmed that ODP was successfully embedded into the beta-PbO2 layer of Ti/Sn-SbOx/PbO2-ODP, increasing the water contact angle at the electrode surface from 75.9 degrees to 133.9 degrees. The Ti/Sn-SbOx/PbO2-ODP electrode exhibited excellent electrocatalytic oxidation of ciprofloxacin (CIP). The pseudo first-order rate constant for CIP removal was 3.92 h(-1) at an electrolytic potential of 10 V, 2.6 times greater than that when using the unmodified electrode. Moreover, electrode stability was greatly improved after ODP modification. The Ti/Sn-SbOx/PbO2-ODP electrode had longer accelerated life (324 h) than the Ti/Sn-SbOx/PbO2 electrode (91 h). The enhanced electrocatalytic performance of Ti/Sn-SbOx/PbO2-ODP was attributed to improved utilization of hydroxyl radicals (center dot OH) resulting from higher oxygen evolution potential. Furthermore, the hydrophobic surface of Ti/Sn-SbOx/PbO2-ODP was beneficial for stronger adsorption of CIP, as evidenced by the initial surface concentration test. (C) 2021 The Electrochemical Society (ECS). Published on behalf of ECS by IOP Publishing Limited.

Automated summary

A novel Ti/Sn-SbOx/PbO2-ODP electrode was constructed using a co-electrodeposition method, with the beta-PbO2 layer modified with ODP to enhance water contact angle and electrocatalytic performance for CIP oxidation. The ODP modification significantly improved electrode stability and accelerated life. The enhanced electrocatalytic performance was attributed to improved utilization of hydroxyl radicals and stronger adsorption of CIP due to the hydrophobic surface.