Study Of Metal Elements Doped Nano-TiO₂ Electrode With High Hydrogen Overpotential And Its Electrocatalytic Property

Electrocatalytic reduction has been widely used in environmental management and biomedical fields.For electroreduction of L-cystine with disulfide bond,Pb electrode often was used as working electrode,but there exists the problem of Pb2+contamination and hydrogen evolution side reaction in acidic electrolyte.In this work,considering that TiO2 electrode is stable in acid solution and better electrocatalytic activity,the modified nano-TiO2 electrode was prepared by doping the metal elements Ce,La,Sn and Bi by sol-gel method,in order to further improve the over-potential of hydrogen evolution and electrocatalytic activity of the Ti02 electrode.The surface morphology and crystal structure of the nano-TiO2 electrode are characterized by X-ray diffraction(XRD)and scanning electron microscopy(SEM).We use the cyclic voltammetry test and polarization curve test to analyze the electrochemical performance of the electrode.This work explores the electrocatalytic reduction properties of modified electrodes for L-cystine.The main results obtained are as follows:(1)Doping Ce,La and Sn metal alone can improve over-potential of hydrogen evolution of TiO2 electrode and its elctrocatalytic activity for reducaiton of L-cystine.Modified Ti02 electrode with a molar ratio of Ce/Ti of 0.01,a molar ratio of La/Ti of 0.005,and a Sn/Ti molar ratio of 0.01 and 0.02,have higher over-potential of hydrogen evolution and elctrocatalytic activity.(2)The modified TiO2 electrodes by co-doping La-Sn,Ce-Sn,Ce-La have high electrocatalytic activity for reduction of L-cystine.For La-Sn and Ce-Sn co-doped electrodes,their over-potential of hydrogen evolution are higher(0.9V-1.2V,at 10 mA/cm2 of current density),and the current density of reduction peak in the CV curve can reach 15mA/cm2.These electrodes were also better stability.(3)Doping one and/or two-elements also can increase the hydrogen evolution over-potential of the electrode to a certain degree.The sintering temperature also affects the hydrogen evolution over-potential and electrocatalytic activity of the modified electrode.The electrode with the same concentration of the same doping element sintered at 500? has the best electrocatalytic performance.