一维TiO2锐钛矿/金红石异相结的制备及光催化降解甲醛性能

TiO₂异相结主要通过高温方法制备，所制备材料的形貌和组成较难控制，尤其是在较低温度下一步制备一维TiO₂异相结仍具有一定的挑战性。采用简单、方便的一步水热法，在较低温度下(180℃)制备了一维纳米TiO₂异相结材料。X射线衍射(XRD)和高分辨透射电镜(HRTEM)分析表明，制备的材料以一维金红石相TiO₂纳米棒(长度：(400±50) nm，直径：(60±5) nm)为基本结构，粒径分布均匀的锐钛矿相TiO₂纳米粒子(直径：(9.5±0.5) nm)高密度、单分散地负载在纳米棒上。通过控制水热反应时间成功调控了异相结中锐钛矿相TiO₂的含量(20%～50%)，进而实现了其光催化降解HCHO性能的调控。实验结果表明，当锐钛矿相TiO₂的含量为33%时(TiO₂-24，水热时间24 h制备的样品)，异相结光催化剂表现出最佳的HCHO降解性能：在低光强LED灯(波长为365 nm，光强为12.26 mW·cm

One-Dimensional TiO2 Anatase/Rutile Heterophase Junctions: Preparation and Photocatalytic Properties for Degrading Formaldehyde

TiO₂ heterophase junctions are mainly prepared by high-temperature method,and it is difficult to control the morphology and composition of the prepared materials.Especially,it is still challenging to prepare a one-dimensional TiO₂ heterophase junction at a lower temperature.In this paper,a simple and convenient one-step hydrothermal method was developed prepared one-dimensional nano-TiO₂ heterophase junctions at a relatively low temperature(180℃).X-ray diffraction(XRD)and high-resolution transmission electron microscopy(HRTEM)analyses show that the one-dimensional rutile TiO₂ nanorods(length:(400±50)nm,diameter:(60±5)nm)are the basic structure of the prepared materials,and the anatase TiO₂ nanoparticles with uniform size distribution(diameter:(9.5±0.5)nm)are loaded on the nanorods in a high-density,monodispersed form.By adjusting the hydrothermal time,the anatase TiO₂ contents in the prepared materials could be controlled within the range of 20%-50%.The TiO₂ heterophase junctions were successfully applied to the photocatalytic degradation of formaldehyde.When the content of anatase phase TiO₂ was 33%(TiO₂-24,the hydrothermal time was 24 h),the TiO₂ heterophase junction had the best formaldehyde degradation performance.After 25 min photocatalytic reaction,the 92%of formaldehyde(120 mg·L^-1)was degraded into CO₂ under a low-intensity LED lamp(wavelength:365 nm,light intensity:12.26 mW·cm^-2),confirming the efficient activity of the TiO₂ heterophase junction.Steady-state fluorescence spectroscopy and photoelectrochemical tests showed that charge separation and transfer efficiencies on TiO₂-24 were much higher than those on other samples prepared at different hydrothermal times.The one-dimensional TiO₂ heterophase junction not only is beneficial to the transfer of photogenerated charge but also can directionally drive the separation of the charges,which makes one-dimensional TiO₂ heterophase photocatalyst has a higher formaldehyde degradation performance.