Rare Earth-Doped Ti/SnO₂-Sb With Different Intermediate Layer For Electrocatalytic Performance

Tin oxide(SnO2)is a hopeful material but its electrical conductivity is not good at room temperature and thus cannot be directly applied to be used as electrode material.The incorporation of a proper dopant can enhance its conductivity and exhibit good electrocatalytic activity,and reduce the preparation cost.In the fabrication of SnO2-based electrodes,various techniques have been progressed,including solution phase methods,gasphase methods,and electrochemical methods.Titanium-based Sb-doped SnO2 electrodes have been recognized as one of the most promising anodes in the electrochemical incineration of organic pollutants.The thermal decomposition method was applied to modify Ti/SnO2-Sb-Mn/Re electrodes with tin and manganese molar ratios and rare earth(Re).The electro-catalytic achievement of electrodes was investigated by using phenol which acted as a model contaminant.The degradation kinetics rate of phenol degradation followed pseudo-first-order in the experimental range.The test results demonstrate that the best degradation rate reaching(?95%)and(?97%)after treatment for 140 min was observed in Mn(1%)/Re and Mn(2%)/Re than that of without Mn electrodes.Accelerated lifetime test displayed that,the bestaccelerated service time could be determined only in Mn(3%)/Re and Mn(4%)/Re compared to another prepared Mn doping(0%,1%,and 2%)/Re electrodes under the condition of 500 mAcm-2 current density in this study.The composite electrodes of Ti/SnO2-Sb-Ni/rare earth have been modified using rare earth elements(Re)Gd,Ce,Eu,and Er and various molar ratios of tin and nickel intermediate layer,and their electrochemical oxidation effects were scrutinized.To analyze the decolorization performance of the electrodes,Rhodamine B(RhB)dye was utilized as a target pollutant.Accelerated life testing indicated that the longer service life could be observed in Ni(3.5%)/Re and Ni(5%)/Re electrodes compared with other modified Ni(0%,1%,and 2%)/Re electrodes.Compared with the color removal efficiencies of the Ni(2%)/Re electrodes,the decolorization rate of 90%after treatment for 60 min and the low energy consumption of 3.621 kW h m-3 can be achieved at the Ni(2%)/Gd electrode under the experimental condition of 100 mg L-1 RhB.The best decolorization rate was observed at the Ni(2%)/Re electrodes among other Ni and no adding Ni-doped Re electrodes.The modified Ti/SnO2-Sb-Co/Re electrodes were fabricated using different rare earth elements(Re=Gd,Ce,Er,and Eu)and various molar ratios of tin/cobalt by thermal decomposition.To scrutinize the electrochemical decolorization performance of electrodes,methyl orange was used and the decolorization rate followed pseudo-first-order kinetic in the experimental time.The experimental results demonstrated that,decolorization efficiencies reach 92%,88%,89%,and 90%on Co(2%)/Gd,Co(2%)/Ce,Co(2%)/Eu,and Co(2%)/Er,respectively,after 25 min electrolysis..Accelerated lifetime tests show that the longest accelerated lifetime was observed only in Co(3.5%)/Re and Co(5%)/Re electrodes compared with other modified Co(0%,1%,and 2%)/Re electrodes at the condition of 1000 mA.cm-2 current density.In this research work,Ti-based SnO2-Sb/rare earth electrodes with different intermediate layers were fabricated successfully by thermal decomposition.Incorporation of an interlayer between the substrate and the active layer effect the electrocatalytic performance and service lifetime.