The Preparation And Performance Studies Of Titanium-based Iridium Manganese Oxide Anode Doped Rare Earth Cerium

With the rapid development of non-ferrous metal smelting and processing enterprises,the discharge and pollution of heavy metal wastewater has become more and more serious.Electrodeposition can be used as a green process to recover heavy metal ions from heavy metal wastewater.In the electrodeposition process,the anode is in the"core"position,and its properties such as electrocatalytic activity and stability directly affect the current efficiency,energy consumption and product quality in the electrowinning process.In this paper,Ti/IrO₂+MnO₂+CeO₂ composite anode containing rare earth element Ce was prepared by sol-gel method.The surface morphology,oxygen evolution electrocatalytic activity and stability of the anode are studied by scanning electron microscopy,oxygen evolution polarization curve,cyclic voltammetry curve,AC impedance diagram and accelerated life experiment.And secondly,the influence rules of the active group matching,calcination temperature and coating loading on the performance of the anode are discussed to find the best preparation parameters.Finally,the effect of self-made anode and traditional anode on cell voltage,current efficiency and energy consumption is compared by the electrolysis of NiSO₄ solution of laboratorial simulated heavy metal wastewater.The results show that the surface morphology of anodes with different Ce content is significantly different.The surface of Ti/IrO₂+MnO₂ electrode which is not doped with Ce is very uneven,with unevenness and pores.The surface of the Ti/IrO₂+MnO₂+CeO₂ electrode doping Ce is relatively flat and uniform,the unevenness is small,and the number of cracks is increased.However,when the Ce content is excessive,the surface of the electrode coating becomes dense and the number of cracks rapidly decreases.With the increase of Ce content,the voltammetric charge,electric double layer capacitance and accelerated life value all increase first and then decrease.And at the same time,they reached the maximum when the Ce content was 10%,that is,the molar ratio of iridium,manganese and cerium was 7:2:1.However,the polarization potential and the oxygen evolution reaction resistance at the same current density reached the minimum value,indicating that the oxygen evolution activity of the Ti/IrO₂?0.7?+MnO₂?0.2?+CeO₂?0.1?anode is the best and that life is the longest.The calcination temperature has a great influence on the surface morphology of the anode coating.The surface crack of the coating is less at 300?,and the crack increases significantly when the temperature is raised to 350?or higher.With the increase of calcination temperature,the voltammetric charge,electric double layer capacitance,oxygen evolution current density and accelerated life value all increase first and then decrease,and reached the maximum at 400?.In-depth study of the electrochemical surface structure of the anode at different temperatures found that when the calcination temperature is less than 400?,the"internal"active surface area of the coating Q^*_in>"external"active surface area Q^*_out,when the temperature is greater than 400?,Q^*_In<Q^*_out,this is due to the presence of more cracks on the surface of the coating prepared at high temperatures,increasing the external surface area.The coating loading has little effect in the early stage and has larger effect latterly on the performance of the anode.When the loading is 10g/m²,the oxygen evolution potential and the voltammetric charge gradually become constant.comprehensive consideration,the best loading is 10g/m².Finally,compared with the traditional anode electrolysis experiments,it is found that the Ti/IrO₂+MnO₂+CeO₂ anode has the lowest tank voltage,the highest current efficiency and the lowest energy consumption under different current density conditions.