热处理工艺对TiO2纳米管阵列结构及其光电性能的影响

通过阳极氧化法在钛箔上制备了TiO2纳米管阵列,在不同热处理工艺下使其晶化.利用扫描电子显微镜(SEM)和X射线衍射(XRD)对TiO2纳米管阵列的形貌和结构进行了表征.结果表明,阳极氧化法制备的TiO2纳米管经450~750℃热处理后为纳米晶结构,平均晶粒尺寸随退火温度升高而增大,相同温度下氮气气氛中热处理的TiO2平均晶粒尺寸小于空气气氛中热处理的TiO2.氮气气氛下退火可拓宽TiO2由锐钛矿型(Anatase)向金红石型(Rutile)结构转变的热处理温度范围,650℃以上退火处理后,TiO2纳米管中掺杂有少量的氮.光照开路电位测试和稳态极化曲线测试结果表明,在氮气气氛中、经650℃退火处理2 h制备的TiO2纳米管阵列电极光电响应性能最佳,此时TiO2为锐钛矿型和金红石型的混晶结构.

Effect of Heat-treatment Process on the Structure and Photoelectric Performance of TiO2 Nanotube Arrays

TiO2 nanotube arrays were made on the titanium foil by the method of anodic oxidation,and then crystallized by different heat-treatment processes.The morphology and structure of the TiO2 nanotube arrays were characterized by SEM and XRD.The results showed that the TiO2 nanotube arrays prepared by anodic oxidation and annealed at the temperature range of 450 750℃ were nanocrystalline structure,and the average measurement of the crystal particle grew with the increasing of the annealing temperature.The average crystal size of TiO2 nanotube arrays annealed in the nitrogen atmosphere is smaller than that annealed in the air atmosphere at the same temperature.Annealing in the nitrogen atmosphere can widen the limit of the transformation temperature from Anatase to Rutile.Annealed above 650℃,the TiO2 nanotube arrays can be doped into a small amount of nitrogen.The results of light open-circuit potential tests and the steady-state polarization curves tests show that the TiO2 namotube arrays electrode has the best photoelectric response properties after being annealed in the nitrogen atmosphere at 650℃ for 2 h.The arrays have mixed crystal structure of Anatase and Rutile.