Influence of Electrolytes on the Photocathodic Protection Effect of TiO2 Nanotube Films for Stainless Steel

The effect of the concentration and the variety of electrolytes(NaNO3,NaCl,Na2SO4,Na2S,NaOH) in a photoelectrolytic cell on photoelectrochemical properties of a TiO2 nanotube film prepared by an anodic oxidation method was studied by photoelectrochemical measurements.The results show that the trend of different electrolytes for capturing photogenerated holes is Na 2 SNaOHNa2SO4 NaClNaNO3.Due to the synergistic effect of Na2S and NaOH in a solution,when the concentrations of Na2S and NaOH were both 0.5 mol / L,the photogenerated electron-hole pairs could be more effectively separated.The potential of 403 stainless steel in a 0.5 mol / L NaCl solution coupled with the TiO2 film electrode in a 0.5 mol / L Na2S+0.5 mol / L NaOH solution decreased by 650 mV under white-light irradiation,indicating the film could provide a good photocathodic protection effect on the steel by the assistance of the electrolyte solution.After the light was cut off,the 403 stainless steel also could be protected to a certain extent by the TiO2 film.