Polystyrene microsphere assisted synthesis of a Co/PEG comodified PbO2 anode and its electrocatalytic oxidation performance

Abstract

• The Co-PEG-PbO 2 electrode was prepared by PS-assisted electrodeposition. • The electrode possess porous structure and high electrocatalytic performance. • The degradation of p-chlorophenol follows the CE mechanism. Highly performed electrode is one of the key factors affecting the efficiency of oxidation toward organic pollutants. To improve the electrocatalytic performance and stability of PbO 2 electrode, a Co-PEG-PbO 2 electrode modified by Co 2+ ion and polyethylene glycol (PEG 6000) was prepared by polystyrene microspheres assisted electrodeposition combined with surface structure adjustment and active substance doping, and used for the effective degradation of p-chlorophenol in water. The results showed that the Co-PEG-PbO 2 electrode surface was composed of small spherical particles β-PbO 2 , containing a small amount of Co 2 O 3 and PEG, and its grain size (8.985 nm) was the smallest in the same series of electrodes. The electrochemical tests results showed that the oxygen evolution reaction in Na 2 SO 4 solution was a sequential two-step charge transfer process, which was controlled by charge transfer and diffusion. The electrode had smaller oxygen evolution potential (1.40 V), larger exchange current density (j 0 = 1.164 × 10 −4 mA · cm −2 ), smaller charge transfer resistance (0.8778 Ω · cm 2 ) and larger concentration polarization resistance (1.335 Ω · cm 2 ), indicating that the Co-PEG-PbO 2 electrode had better electrocatalytic performance. The degradation of p-chlorophenol was controlled by diffusion and was oxidized by strong oxidizing · OH, which conforms to CE mechanism. Within the same degradation time, the electrode had a higher p-chlorophenol removal efficiency η (97.34%), higher TOC removal efficiency (64.25%), higher mineralization current efficiency (23.45%), and lower cell voltage. The accelerated life test showed that Co-PEG-PbO 2 electrode had the longest service life (280 min), which was 2.8, 1.8 and 2 times of PbO 2 electrode, Co-PbO 2 electrode and PEG-PbO 2 electrode, respectively. The electrocatalytic activity and stability of PbO 2 electrode can be effectively improved by structural adjustment and co-doping with Co 2+ and PEG, which can be used for the effective degradation of p-chlorophenol.