木材表面Fe^(3+)掺杂TiO_2/SiO_2复合膜构建及其光催化性能

Construction of Fe^(3+) doped TiO_2/SiO_2 composite film on wood surface and its photocatalytic activity

以速生人工林桉木为基体,利用溶胶-凝胶技术,将掺杂Fe^(3+)的TiO_2/SiO_2复合膜构建在桉木材表面。通过X射线衍射仪(XRD)、傅里叶红外光谱(FT-IR)和扫描电镜(SEM)等手段分析了复合材料的微观形态;以10mg/L的甲基橙溶液为目标降解物,研究了负载复合膜的木材光催化活性。结果表明,生成的复合膜中TiO_2以锐钛矿晶型存在,SiO_2以无定型状态存在,由于Fe^(3+)的离子半径小于Ti^(4+),铁离子以物理状态掺杂进入TiO_2晶格。FT-IR光谱图显示,在1 026 cm^(-1)左右形成Ti—O—Si键,说明硅钛前驱体发生了相互作用。SEM图结果表明,复合膜与木材结合紧密。光催化测试结果表明,当Fe^(3+)掺杂量为0%~5%时,随着Fe^(3+)掺杂量的增加,负载复合膜的木材对甲基橙的降解率先上升后下降,当Fe^(3+)掺杂量为1%时,降解率达到最大值40.37%。

In order to create self-cleaning wood surface,the Fe（3＋） doped TiO2/SiO2 composite film was constructed on the eucalyptus wood surface by using the sol-gel technique,which can increase the bandgap of TiO2 to prevent photogenerated electron-hole recombination and improve its photocatalytic efficiency. The microstructures of the composite were investigated by means of the X-ray diffraction（ XRD）,Fourier transform infrared spectroscopy（ FT-IR） and scanning electron microscopy（ SEM）. The photocatalytic activity of the composite film was examined by using the methyl orange solution with a mass concentration of 10 mg/L as the target degradation product. The results showed that the TiO2 in the composite film was presented in the anatase crystal form,and the SiO2 was in the amorphous state. Because the ionic radius of Fe（3＋） was smaller than that of the Ti（4＋）,the iron ions were physically doped into the TiO2 lattice. The results of FT-IR spectroscopy showed that the Ti—O—Si bonds were formed in the range of 1 026 cm（-1）,indicating that the interaction of Si—Ti precursors. It could be found that the composite membrane was tightly combined with the wood through the results of the SEM images,and the composite film thickness was within 50 nm. The results of photocatalytic test showed that the untreated wood did not degrade methyl orange,the degradation ability of methyl orange was obviously enhanced after loading wood composite with Fe（3＋）,and the degradation rate of methyl orange loaded with composite membrane firstly increased and then decreased with the increase of Fe（3＋） doping amount in the range of 0%-5% Fe（3＋）doping. When the content of Fe（3＋） doping was 1%,the degradation rate reached a maximum of 40.37%,and the reason was that the doping of Fe（3＋） accelerated the electron-hole separation and enhanced the catalytic performance of the composite,while the excessive Fe（3＋） would hinder the photocatalytic performance of the TiO2.