Studies of the electrochemical reduction processes of Bi3+, HTeO2+ and their mixtures

The reduction process of Bi3+, HTeO2+ and their mixtures on Au electrode surface was studied by cyclic voltammetry, linear sweep voltammetry, electrochemical impedance spectroscopy and chronoamperometry. XRD and EDS methods were also used to measure the reductive products prepared under different potentials and provide the evidences of the reactions. The results indicate that the reduction of HTeO2+ occurs at more positive potential than that of Bi3+, but its reduction rate is slower and adsorption phenomenon exists during its reduction process. Bi2Te3 compound can be obtained potentiostatically at a proper potential in all the mixed solutions with concentration ratio image in our research range (0.1–10). But pure Bi2Te3 compound can only be obtained at 42 mV in the solution with concentration ratio image equaling to 1. And the formation of Bi2Te3 compound is an inductive co-depositing process: (1) HTeO2+ + 4e− + 3H+ → Te0 + 2H2O, (2) 3Te0 + 2Bi3+ + 6e− → Bi2Te3.