TiO2/羟基磷灰石的结构及其光催化降解醛类的性能

 采用水热合成和离子交换法相结合制备了不同Ti/(Ti+Ca)摩尔配比的羟基磷灰石负载二氧化钛(TiO2/HAP)光催化剂. 用X射线衍射、拉曼光谱、红外光谱、紫外-可见漫反射光谱和微型连续光反应技术研究了催化剂的晶体结构、表面构造、光响应性能以及光催化降解甲醛和乙醛的性能. 结果表明, Ti/(Ti+Ca)配比是影响TiO2/HAP晶体结构、表面构造和光响应性能的重要因素, Ti/(Ti+Ca)摩尔比为 0.2时, TiO2/HAP为锐钛矿型TiO2和HAP的混合相, TiO2与HAP之间形成了 Ti-O-P 键,二者得到了有效的复合. 复合材料相对于TiO2在漫反射光谱吸光带边上有明显的红移,扩展了材料的吸光域. 在合适的条件下, TiO2/HAP光催化降解甲醛和乙醛的转化率分别达89.2%和82.7%, 矿化率达92.1%和75.2%.

The Structure of TiO2/Hydroxyapatite and Its Photocatalytic Performance in Degradation of Aldehyde

TiO_2/hydroxyapatite (HAP) catalysts with different Ti/(Ti Ca) atomic ratios (x) have been successfully synthesized by hydrothermal and ion-exchange methods. The crystal structure, surface composition, and photoabsorption performance of the catalysts were characterized by X-ray diffraction, Fourier transform Raman spectroscopy, Fourier transform infrared spectroscopy, and UV-Vis diffuse reflectance spectroscopy. The photocatalytic activity of the catalysts for the degradation of aldehyde was investigated in a photoreactor. The sample with x=0.2 had the characteristic crystal phase of both hexagonal hydroxyapatite and anatase. A significant red shift of the absorption peak edge was brought out owing to the matching of the energy level between HAP and TiO_2. The degradation of formaldehyde or acetaldedyde over TiO_2/HAP was more effective than that over pure HAP or TiO_2. The conversion was 89.2% and 82.7% with the mineralization rate of 92.1% and 75.2%, respectively, under proper conditions over TiO_2/HAP with x=0.2.