通过正交试验分析不同阳极氧化电压、氧化时间、氧化次数以及热处理温度对TiO2纳米管阵列电极性能的影响机理,使用电化学工作站测试电极光电化学性能,结合扫描电子显微镜、X射线衍射、紫外一可见漫反射光谱等表征手段着重研究影响电极催化性能的内在机理。结果表明:不同阳极氧化和热处理使电极获得不同的微观结构和晶型,导致电极光催化性能差异明显。60v恒压下1次阳极氧化1h的样品经500℃热处理后,保持规整的纳米管阵列结构和较大的活性面积,并获得了特殊的分层混晶结构,具有较好的催化活性。同时,使用同一电极进行多次光催化制氢反应。紫外光照下,在0.5mol/LNa2SO4+0.5mol/L乙二醇水溶液中,0.5V偏压下获得了5.3mL/(h.cm^2)的稳定产氢速率,证明电极具有稳定的光催化制氢活性。
The relationship between the preparation conditions and photocatalytic hydrogen evolution properties on TiO2 nanotube array electrodes was discussed. The influences of anodization potentials, durations, counts and thermal treatment temperature on the electrode performance were investigated via an orthogonal test. The electrodes were characterized by scanning electron microscopy, X-ray diffraction and UV-Vis diffuse reflectance spectroscopy, respectively. The photoelectrochemical properties of electrodes were also examined by an electrochemical work station. The underlying mechanism was analyzed. The results show that TiO2 nano- tube-array electrodes prepared at different parameters of anodic oxidation and thermal treatment lead to different microstructures and crystalline phase compositions, and consequently affect the photocatalytic performances. The highly-ordered TiO2 nanotube arrays are achieved after first-step anodization at 60 V for 1 h. The layered mixed crystal is obtained by heat treatment at 500 ~C. Furthermore, the multiple photocatalytic experiments were conducted using one electrode in 0.5 mol/L Na2SO4+0.5 mol/L ethylene glycol water solutions under UV light. The H2 evolution rate is 5.3 mL/(h-cm^2) at a bias voltage of 0.5 V. The electrode exhibits superior photo- catalytic stability.