TiO2纳米粒子膜的表面态性质及其光催化活性的研究

TiO₂纳米粒子膜催化剂光催化降解水中污染物,与粉末相比具有可重复使用、易回收等优点,近年来,在光化学领域受到人们的高度重视^[1～3].膜催化剂的表面性质与其光催化活性直接相关,研究这些性质能够为研制、开发高效催化剂提供理论依据.本文采用TiCl₄水解法,制备了酸性、碱性条件下TiO₂纳米粒子膜.利用原子力显微镜(AFM)、X-射线衍射谱(XRD)、红外光谱(IR)和场诱导表面光电压谱(EFISPS)测定其表面微结构.考察了它们对苯酚降解的光催化活性,讨论了膜催化剂的表面性质对光催化活性的影响.

RELATIONSHIP OF PHOTOCATALYTIC ACTIVITY AND SURFACE STATES OF TiO2 NANOPARTICLE FILM

TiO2 nanoparticle film catalysts have been prepared in acid and basic conditions respectively, by method of the hydrolysis of TiCl4. Their surface microstructures and surface energy levels were tested by infrared (IR) spectra and electrical field induced surface photovoltage spectra (EFISPS). The results demonstrate that surface properties of the two kinds of TiO2 films are different. A new peak at 1350 cm-1 due to superoxide radical appears in the IR spectrum of TiO2 powder prepared by basic condition, while it is not found in the one prepared by acidic condition. Furthermore, a new peak at 390nm attributed to Ti3+ surface state is also found in EFISPS of the film obtained from basic colloid, whereas the peak disappears in EFISPS of the film obtained from acidic colloid. Photodegradation of phenol shows that photocatalytic activity is affected by surface properties of the film. Photocatalytic activity of the latter is better than that of the former confirms that Ti3+ reduces photocatalytic activity of catalyst.