电解质对TiO2纳米管阵列膜光生阴极保护效应的影响

基于光电化学测试考察了光电解池中电解质(NaNO₃, NaCl, Na₂SO₄, Na₂S和NaOH)的种类和浓度对阳极氧化法制备的锐钛矿型TiO₂膜电极光电性能的影响, 并解释了其作用机理.结果表明, 电解质捕获空穴的能力顺序为Na₂S>NaOH>Na₂SO₄>NaCl>NaNO₃.Na₂S和NaOH在溶液中具有协同作用, 当两者组成混合溶液并且浓度均为0.5 mol/L时, 更有利于TiO₂膜光生电子-空穴对的分离和光电转化性能的提高.当0.5 mol/L NaCl溶液中的403不锈钢(403SS)与0.5 mol/L Na₂S+0.5 mol/L NaOH混合溶液中的TiO₂膜电极耦连时, 光照膜电极可使403SS的电极电位负移约650 mV, 具有良好的光生阴极保护效应.当切断光源时, 在该混合液中TiO₂膜也能对403SS起到一定的阴极保护作用.

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 Na₂S>NaOH>Na₂SO₄>NaCl>NaNO₃. 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.