The Preparation Of Nd Doped PbO₂ Electrodes And The Electrochemical Oxidation Of BPS

Bisphenol S(BPS)is harmful to the environment and organisms.It makes sense to remove it from environment.Electrocatalytic oxidation technology has been widely concerned in the removal of toxic substances and refractory organics due to its high removal efficiency and cleanness.In this paper,a series of neodymium(Nd)doped PbO2 electrodes(Ti/PbO2-Nd)were synthesized by pulse electrodeposition,and their activities of BPS removal were investigated.The microstructure of the electrode surface was characterized by XRD,SEM and EDS.The electrochemical property of electrodes was tested by CV and LSV.The performance,energy consumption and mechanism of Ti/PbO2-Nd electrodes for bisphenol S electrocatalytic oxidation were discussed.Ti/PbO2-Nd electrode showed higher activity in the process of bisphenol S anodization compared to the Ti/PbO2 electrode.The BPS removal efficiency became better with the increase content of Nd.When Pb:Nd was 10:1,the effect was the best.Over 95%bisphenol S was degraded under current density of 15 mA/cm2 with initial BPS concentration of 5 mg/L within 60 min.Nd-doping promoted the oxygen evolution potential(OEP)of the PbO2 electrode from 1.41V to 1.55V.Meanwhile,it contributed to the increase of specific surface area according to CV curves,and significantly promoted the production of reactive oxide species.SEM results showed that finer crystal particles were generated on the surface of Ti/PbO2-Nd electrode.In addition,lower pulse duty cycle during electrode preparation was also helpful for crystal refinement.When the pulse duty cycle was 50%,the effect was the best.Element Nd existed in the form of Nd2O3 based on XRD analysis.Moreover,the strongest characteristic peak of PbO2 changed from ?(301)to ?(110).Ti/PbO2-Nd electrode showed high chemical stability.The energy consumption during bisphenol S degradation on Ti/PbO2-Nd electrode was 60.26 kWh/m3,much lower than that on Ti/PbO2 electrode(95.45 kWh/m3).The effects of different parameters on BPS degradation were investigated with Ti/PbO2-Nd electrode as anode.The results showed that the removal efficiency of BPS in Na2SO4 electrolyte solution is better than that in Na2CO3 and NaNO3 solution,and it was the highest when the concentration of Na2SO4was 0.1mol/L.After increasing the current density from 5 to 25 mA/cm2.BPS removal efficiency rose from 35.76%to 98.47%.And BPS was degraded faster at low concentration.In addition,Ti/PbO2-Nd electrode could be applied in a wide range of pH. The derivation of electrolysis products and mechanism analysis showed that the BPS degradation was achieved by the oxidation of·OH and·SO4-.Nd-doping improved the OEP of the electrode and promoted the increase of reactive oxide species,which prevented the occurrence of oxygen evolution side reaction.The process of BPS electrocatalytic oxidation on Ti/PbO2-Nd electrode first underwent two rounds of hydroxylation oxidation on the electrode surface followed by ring opening oxidation.And BPS degradation course followed the pseudo-first order reaction kineticsAll above demonstrate that Ti/PbO2-Nd electrode is in good stability with high removal efficiency and low energy consumption.