Surface analysis of Ti/Sb-SnO2 electrode after electrolysis

The change in the surface morphology in electrochemical processes can directly affect the stability of the electrode. Ti/Sb-SnO2, the target electrode, was electrolyzed in the Na2SO4 solution (0.1 mol·L-1) under constant current density condition (5×10-3 A·cm-2) for 300 h. scanning electron microscope, energy dispersive spectrometer and X-ray diffraction (XRD) were used to determine the change in the surface morphology. Inductively coupled plasma optical emission spectrometry was used to determine the metal content in the electrolyte. Then the possible reason for the deactivation of the Ti/Sb-SnO2 electrode after long time running was proposed. The SEM results show that the surface layer of the Ti/Sb-SnO2 electrode was partially dissolved and some parts were even detached from the titanium base after electrolysis. The Sn element was detected in the electrolyte after electrolysis, suggesting that Sb-SnO2 was indeed dissolved in the electrolyte. The XRD analysis indicates that the surface layer was still Sb-SnO2 but the diffraction peak intensity decreased. It appears that the anode deactivation may result from the dissolution and detachment of the oxide layer and the passivation of substrate. The result can be useful for the enhancement of the electrode stability.