Pd纳米晶修饰TiO2纳米管阵列光电极的制备及性能

Preparation and performance of Pd nano-crystallite decorated TiO2 nano-tubes arrays photoelectrode

摘要:

为提高TiO₂的可见光催化性能,采用阳极氧化法在Ti箔上原位生成TiO₂纳米管阵列,再利用阴极电沉积法制备了贵金属Pd纳米晶修饰的TiO₂纳米管阵列光电极,并利用扫描电子显微镜（SEM）、X-射线光电子能谱（XPS）及紫外-可见漫反射光谱（UV-vis DRS）对其表观形貌、表面形态及光吸收性能进行表征．结果表明:Pd纳米晶有效地修饰在TiO₂纳米管阵列的表面,且以Pd⁰形式存在．此外,Pd纳米晶修饰明显拓展了TiO₂纳米管阵列的可见光响应范围．以甲基蓝为模型污染物,重点考察阴极沉积电压及沉积时间对其光催化性能的影响．结果表明:阴极沉积电压为-0.8 V、沉积时间为10 min对甲基蓝的光催化降解效果最佳,且符合拟一级反应动力学模型．模拟太阳光下光照120 min对甲基蓝的降解率可达71.4％,是纯TiO₂纳米管阵列光电极的1.5 倍．

Abstract:

To improve the visible light photocatalytic activity of TiO₂, in this study, TiO₂ nano-tubes arrays (TNTAs) were in-situ grown by anodization of Ti foils, and noble Pd nano-crystallites were electrochemical deposited onto the as-prepared TNTAs photoelectrode. The morphology, surface state and light absorption ability of the resulting electrodes were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and UV-visible light diffuse reflection spectroscopy (UV-vis DRS), respectively. It was found that Pd nano-crystallites were successfully decorated onto the surface of TNTAs electrode, and existed as the form of Pd⁰. In addition, the light absorption of Pd／TNTAs photoelectrode was greatly red-shifted to visible region. Furthermore, methyl blue (MB) was served as the probe molecules, and the effects of deposition voltage and time on the photocatalytic (PC) performance were mainly investigated. It was found that when the deposition voltage and time were -0.8 V and 10 min, respectively, the optimal photodegradation of MB could be obtained, which fitted well with the pseudo-first-order kinetics formula. Under the simulated sunlight irradiation within 120 min, the 71.4％ degradation rate of MB could be achieved, which was 1.5 times larger than that of bare TNTAs photoelectrode.