Preparation and electrochemical properties of Pb-Ag/MnO2 coated anode for zinc electrodeposition
Lead-silver alloy(Pb-Ag)is the most widely used anode material in zinc electrowinning and other metallurgical processes.With the gradual increase of energy saving and environmental protection requirements,it is difficult to apply Pb-Ag anode to the development of green industrial system due to the disadvantages of low overpotential and poor stability.Improving the oxygen evolution catalytic activity,reducing energy consumption and enhancing corrosion resistance of Pb-Ag/MnO2 anode has become an urgent industrial problem to be solved.In this paper,a thin film coating of manganese dioxide nanoparticles was prepared on Pb-Ag anode by constant current electrodeposition,and the organization and electrochemical properties of the anode were tested.It was shown that the loose cracked structure on the surface of the MnO2 coating not only improved the catalytic activity but also promoted the mass transfer process,which made the oxygen evolution reaction activity and stability of the Pb-Ag/MnO2 anode better than that of the Pb-Ag anode.Among them,the oxygen evolution overpotential of the Pb-Ag/MnO2 anode is 555 mV,and the Tafel slope is 208.5 mV/dec,which is superior to the oxygen evolution overpotential and Tafel slope of the Pb-Ag anode.Meanwhile,the Pb-Ag/MnO2 anode shows good oxygen evolution reaction activity and corrosion resistance in the long-cycle zinc electrolysis experiments,and its tank voltage is about 0.1 V lower than that of the Pb-Ag anode,and the energy consumption is also lower than that of the Pb-Ag anode.
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