Preparation And Electrochemical Performance Of WC Modified Rod-shaped Titanium-coated Aluminum-based Lead Dioxide Electrode Material

The anode materials used in the industrial electrowinning zinc industry are mainly lead anodes.Such anode materials have many problems such as low mechanical strength,easy to dissolve the anode,easy deformation,and polluted the quality of cathode zinc products.Researchers have proposed various methods to solve these problems,such as:adding some other metals to lead anode materials to form binary or multi-element alloys to improve the electrochemical performance of lead anodes;using titanium-based PbO₂ anodes replace traditional lead anodes.Among them,Ti/PbO₂ composite anodes have low energy consumption,high current density,better electrocatalytic activity,long service life,and high-quality cathode products,and they are expected to replace the traditional lead-silver alloy anodes in the hydro metallurgical industry.But the shortcomings are also obvious,there are problems such as high internal stress,the plating layer easily to fall off,high oxygen evolution potential,and high complexity of the preparation process,which restricts its application in actual production.In this dissertation,titanium-based lead dioxide electrodes are used for these problems.The rod-shaped titanium-coated aluminum?Ti/Al/Ti?coated with aluminum as the inner core titanium tube is used as the electrode substrate,and the pulse electrodeposition method is used.The functional WC micro-particles were used to modify the electrode coating,and a WC modified rod-shaped titanium coated aluminum-based lead dioxide composite anode material was prepared.Using scanning electron microscopy,anodic polarization curves,and Tafel curves,single-factor methods were used to study the effect of different preparation conditions on the microscopic morphology and electrochemical performance of the anode material coating,and the optimum composite electrode was determined.The preparation process conditions are:Pb?NO₃?₂ concentration 210g/L,NaF concentration 0.5g/L,Cu?NO₃?₂ concentration 25g/L,AEO-7 concentration 0.5g/L,WC addition 40g/L,average pulse current density 31.25mA/cm²,magnetic stirring speed 210r·min^-1,plating temperature 50?,plating time 50 min.A variety of physical and electrochemical characterization methods were used to study the effect of the functionalized WC particles'addition on the phase composition,microstructure,and oxygen evolution electrocatalytic properties of composite electrode coatings.The physical analysis results show that the main components of the electrode coating are?-PbO₂ and a small amount of WC,and WC is unevenly distributed in the PbO₂ coating;the doping of the functional particles WC can significantly change the surface morphology of the coating,and adding WC can reduce the grain size of the?-PbO₂-WC composite electrode makes the electrode plating more compact;the composite electrode with a WC concentration of 40 g·L^-1in the plating solution has a uniform and compact microstructure and a small grain size,and the microstructure defects are less.The results of electrochemical analysis showed that the?-PbO₂-WC composite electrode prepared with 40 g·L^-11 WC had the lowest oxygen evolution overpotential,the highest exchange current density and the lowest activation energy.In addition,the value of the electric double layer capacitor C_d11 in the charging process is four times larger than that of the pure lead dioxide electrode,and the charge transfer resistance R_ctt value during the oxygen evolution reaction process is the smallest,and at the same time,the corresponding electric double layer capacitor Q_dll is the largest.Moreover,the electrocatalytic stability of the composite electrode was significantly improved after WC doping.SEM,XRD,LSV,CV,and CA were used to investigate the effects of different substratesonphasecomposition,microstructure,andoxygenevolution electrocatalytic properties of the electrode composite coatings.The analysis results show that the Ti/Al/Ti rod substrate can significantly reduce the grain size of the PbO₂-WC composite electrode coating,and the electrode surface becomes more dense;compared with Ti/PbO₂-WC composite electrode,the Ti/Al/Ti/PbO₂-WC composite electrode has a uniform and dense microstructure and a smaller grain size.At the same time,the Ti/Al/Ti/PbO₂-WC composite electrode exhibits a lower oxygen evolution overpotential?,higher exchange rate.Current density j⁰,and better electrocatalytic performance.At the same time,its electrocatalytic stability has also been improved.