TiO2纳米孔薄膜负载meso-四（4-甲氧基苯基）卟啉的正交优化

Orthogonal optimization of the process for attaching meso-tetra（4-methoxyphenyl）porphyrin on nanoporous TiO2 thin film

先采用阳极氧化法,以两步施加电压的方式在钛片表面制备了具有纳米孔结构的TiO2薄膜。然后采用周期换向脉冲电沉积法将光敏剂meso-四(4-甲氧基苯基)卟啉(TPMP)负载到TiO2纳米孔薄膜上。通过电化学阻抗谱和有无光照下的开路电位-时间曲线测试来分析TPMP负载的薄膜的光电性能。以电化学反应电阻Rr和有无光照下的开路电位变化量Δφoc为指标,利用正交试验研究了溶液温度、平均电流、负载总时间、正/反向占空比和正/反向脉冲时间对TPMP负载的TiO2薄膜光电性能的影响。结果表明,影响占主导的因素为溶液温度、正向占空比和平均电流,其次为负载总时间、反向脉冲工作时间和反向占空比,影响最小的是正向脉冲工作时间。最佳的负载工艺参数为:溶液温度45℃,平均电流60 mA,正向占空比20%,反向占空比50%,正向脉冲工作时间80 ms,反向脉冲工作时间5 ms,负载总时间40 min。该条件下所得TPMP负载的TiO2纳米孔薄膜在有无光照下的开路电位变化量最大,有光照下的电化学反应电阻最小。

TiO2 thin films with nanoporous structure were prepared on titanium substrate by anodic oxidation in a two-step voltage control mode, and then attached with meso-tetra(4-methoxyphenyl)porphyrin(TPMP), a photosensitizer, using periodic reverse pulse electrodeposition. The photoelectric property of TPMP-attached thin film was analyzed by open circuit potential(OCP) measurement and electrochemical impedance spectroscopy with and without illumination. The effects of electrolyte temperature, average current, total attaching time, positive and negative duty cycle, as well as positive and negative working time on the photoelectric property of TPMP-attached thin film were studied based on orthogonal design of experiment through assessing the electrochemical reaction resistance Rr and the difference between OCP with and without illumination. The results showed that the dominant factors are electrolyte temperature, positive duty cycle, and average current, the minors are total attaching time, negative working time, and negative duty cycle, and the least important one is positive working time. The optimal attaching process parameters are: electrolyte temperature 45℃, average current 60 mA, positive duty cycle 20%, negative duty cycle 50%, positive working time 80 ms, negative working time 5 ms, and total attaching time 40 min. The TPMP-attached nanoporous Ti O2 thin film obtained thereunder has the lowest Rr under illumination and the largest Δφoc.