The Effects And Its Application Basic Research Of Different Composite Intermediate Layers On The Performance Of Ti/SnO₂-Sb-La Electrodes And Its Application Basic Study

With the accelerating process of industrialization in China,a large proportion of organic wastewaters,coking wastewater in the metallurgical industry is a typical organic wastewater,have become increasingly polluted.These wastewaters have complex compositions,high COD and toxic substance contents,and large p H variations.Traditional biochemical treatment methods cannot effectively handle such wastewater.In recent years,Ti/Sn O₂-Sb electrode materials have attracted great attention from researchers in the field of electrochemical oxidation water treatment with higher oxygen evolution potential and good electrocatalytic activity.The poor adhesion between the Ti/Sn O₂-Sb electrode coating and the substrate,easy to fall off,and short service life limit its industrial application.Aiming at these problems,this work uses a method in which the Sn O₂-Sb active layer is doped with rare earth oxides and the composite intermediate layer is added simultaneously.Based on a study of titanium-based rare earth La tin oxide electrodes,two Ce-Mn and Fe-Mn composite intermediate layers were prepared by the sol-gel method as intermediate layers of the Ti/Sn O₂-Sb-La electrodes.The surface morphology,crystal structure,electrochemical performance and the electrode service life of different Ti/Sn O₂-Sb-La electrodes with different Ce-Mn and Fe-Mn composite intermediate layers,a single Mn intermediate layer and no intermediate layer were compared.Finally,the prepared electrode is used to treat phenol as a pollutant in the simulated coking wastewater.The electrocatalytic activity of the various electrodes was further evaluated to reveal the mechanism by which the composite intermediate layers influence electrode performance.The results show that the introduction of Fe-Mn and Ce-Mn composite intermediate layer and Mn single intermediate layer can significantly reduce the crack on the electrode surface,making the electrode surface more uniform and dense.The thickness of the electrode coating is increased by more than 2 times,so that the electrode surface active material loading is increased,thereby improving the stability of the electrode.The addition of the Ce-Mn composite intermediate layer not only makes the crystal structure of the Sn O₂ in the electrode active layer higher and refines the crystal grains,but also increases the specific surface area of the electrode and the number of reactive sites,and can increase the Oads content of the produced oxygen.The surface of the electrode can adsorb more hydroxyl radicals.In addition,the electrode oxygen evolution potential,the reaction resistance(R_ct)and the oxide film resistance（R_f）are lowered,and the electrode donor density N_Dis increased,which improves the electrochemical performance and electrocatalytic activity of the electrode.The capacity for electrocatalytic oxidationdegradation of phenol was enhanced to some degree,with the highest removal rate of phenol reaching 88.8%after treatment for 120 min,and the maximum removal rate of COD can reach77.92%.In the process of degrading phenol,the cell voltage of the electrode is kept to a minimum,and the stability is maximized.Compared with that of the no-intermediate-layer electrode,the lifetime of the electrode with the Ce-Mn composite intermediate layer was increased 5-fold,with the longest lifetime reaching85 minFurther,the effects of different proportions of Ce-Mn composite interlayer on the performance of the electrode were investigated.The results show that the electrochemical properties and stability of the electrode increase with the increase of the ratio of Ce and Mn,when the ratio of Ce and Mn is increased.At 3:1,the performance of the electrode is optimal,exhibiting excellent electrocatalytic activity and good stability.The experimental results provide an important technical basis and theoretical basis for the preparation of high performance titanium-based tin dioxide composite intermediate layer and its influence on electrode performance.At the same time,it provides new technical support for the effective treatment of organic wastewater with coking wastewater as a typical.