Preparation Of PbO₂ Composite Electrode And Study On Electrocatalytic Degradation Of Nitrogen-containing Heterocyclic Dyes

Titanium-based lead dioxide electrodes are widely used in industrial field and environmental pollution due to their stable chemical properties,good electrical conductivity and strong corrosion resistance.However,lead dioxide electrodes gradually expose defects such as easy falling off of coatings and low catalytic activity.Lead dioxide electrodes can not meet the needs of industrialization.In this paper,Ce-Pb O₂/Zr O₂and Pb O₂/α-Al₂O₃composite electrodes were prepared by composite electrodeposition method.Some characterization methods,such as SEM,XRD,enhanced accelerated life,CV were used to characterize the newly prepared electrodes.The experimental results show that the surface structure of the newly prepared electrodes is compact,the grain size is fine,the oxygen evolution overpotential is high,the enhancement life is long,and the electrocatalytic activity is high.The Ce-PbO₂/ZrO₂composite electrodes was successfully prepared by a composite electrodeposition method in a lead nitrate solution containing cerium ions and Zr O₂particles.SEM images and XRD results show that the Ce-Pb O₂/Zr O₂composite electrodes is dense and has fine crystallites.Ce-Pb O₂/Zr O₂composite electrodes has higher oxygen evolution potential and stability than Ce-Pb O₂electrodes.The lifetime of the Ce-Pb O₂/Zr O₂composite electrodes reached 318h,which was 4.2 times that of the Ce-Pb O₂electrodes（74h）.The acridine orange（AO）was degraded by electrochemical oxidation using a novel Ce-Pb O₂/Zr O₂composite electrodes as the anode.The effects of AO initial concentration,current density and initial p H,and Na₂SO₄concentration on AO removal rate were discussed.The results showed that under the optimal conditions,the initial concentration was 30mg L^-1,the current density was 50m A cm^-2,the initial p H was 5.0,the Na₂SO₄concentration was 0.05mol L^-1,and the AO was completely removed after 90 min of electrolysis.In addition,the stable by-products produced during electrochemical degradation were identified by HPLC-MS,and the possible degradation pathways of AO were elucidated.The results show that AO and its by-products can be effectively removed and mineralized into CO₂,H₂O,ammonium and nitrate ions.A novel PbO₂/α-Al₂O₃ composite electrodes was successfully prepared by composite electrodeposition technique and applied to the electrocatalytic degradation of neutral red（NR）.The effects ofα-Al₂O₃particles on the surface morphology,structure,stability and electrochemical properties of Pb O₂/α-Al₂O₃composite electrodes were investigated.The results show that the addition ofα-Al₂O₃particles can refine the crystal size of lead dioxide and form a dense crystal structure.The Pb O₂/α-Al₂O₃composite electrodes has a larger electrochemical active surface area,stronger hydroxyl radical generation ability and lower charge transfer resistance than the Pb O₂electrodes.The addition ofα-Al₂O₃particles significantly improves the stability of the composite electrode.The accelerated lifetime of the Pb O₂/α-Al₂O₃composite electrodes is 168h,which is 4.8 times that of the Pb O₂electrodes（35h）.Electrochemical oxidation experiments show that Pb O₂/α-Al₂O₃composite electrodes has higher neutral red and COD removal efficiency,lower energy consumption and minimum Pb dissolution than Pb O₂electrodes.Finally,the electrocatalytic degradation pathway of neutral red on Pb O₂/α-Al₂O₃composite electrode was proposed.These results indicate that the Pb O₂/α-Al₂O₃composite electrode has greater application potential in the field of electrocatalytic degradation.