The electrochemical behavior of tellurium on stainless steel substrate in alkaline solution and the illumination effects

• The reductions for tellurium can be promoted by the illumination.
• Effects of illumination is owning to photo-induced electrons.
• Electrocrystallization of tellurium follows a 3D progressive nucleation mechanism.

The electrochemical behavior of tellurium on stainless steel plate substrate in alkaline solution and the illumination effects are investigated by utilizing cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy. Cyclic voltammetry results indicate that Na2TeO3 is firstly reduced to Te and Te is further reduced to Na2Te. These reduction processes are all controlled by mass transfer. The reductions for tellurium electrodeposition under illumination can be promoted affirming by a more positive reduction potential and a higher reduction current. Photocurrent transient demonstrates that the influence of light on accelerating the deposition rate is owning to electrons excitated from the valence band to the conduction band of tellurium. Chronoamperometry measurements indicate that the electrocrystallization of tellurium follows a 3D progressive nucleation and diffusion-limited growth mechanism. Impedance spectroscopy analysis show that the illumination can reduce the Faraday resistance and promote the rate of cathodic reduction owning to the photoconductive effect and the photogenerated electrons injected to the electrolyte. Electrodeposition under illumination can be a good method to produce tellurium in aqueous alkaline solution.