Sputter Depositions of High Performance Photocatalyst

采用反应磁控溅射技术，在无碱玻璃基片上沉积了厚度约为500 nm的TiO_2薄膜。为了保持非常高的沉积速率，在金属和反应性（氧化物）溅射模式之间的“过渡区域”中进行沉积，其中靶表面分别是金属的和氧化的。在总气压为3.0 Pa时，PCU在整个“过渡区”成功地进行了稳定沉积。沉积在过渡区的薄膜均为非晶态结构，光催化活性很低。在高于300 ℃的空气中退火后，所有薄膜均晶化为多晶结构。它们在紫外光照射下既表现出乙醛的光诱导分解又表现出光诱导亲水性。最高 ...更多信息 本研究中在“过渡区”存款光催化TiO_2薄膜的沉积速率为90 nm/min，比常规溅射沉积法提高了20倍以上。在600 ℃、100%氧气总气压为5.0 Pa的条件下，采用反应溅射法制备了WO 3薄膜，在可见光照射下，该薄膜具有明显的光催化降解乙醛的性能和光致亲水性。在440 nm处的量子产率约为1.3%。通过（ahv）^<1/2>对光子能量的曲线外推，估计该膜的光学带隙为2.8eV，其中a、h和v分别为吸收系数、普朗克常数和光频率。因此，光催化反应对应于电子的带间跃迁。WO_3薄膜的这些光催化性能与沉积条件密切相关，从而与薄膜的光学带隙能量密切相关。少

TiO_2 films with the thickness of about 500nm were deposited on unheated non-alkali glass substrates by reactive magnetron sputtering using one Ti metal target with unipolar pulsed powering of 50 kHz and the plasma emission feedback system (PCU). In order to keep the very high deposition rate, the depositions were carried out in the "transition region" between the metallic and the reactive (oxide) sputter mode where the target surface was metallic and oxidized, respectively. Stable deposition was successfully carried out in the whole "transition region" with PCU at total gas pressure of 3.0 Pa. All the as-deposited films deposited in the "transition region" showed amorphous structure, which performed very low photocatalytic activity. After the post-annealing in air at higher than 300 ℃, all the films crystallized to anatase polycrystalline structure. They performed both photoinduced decomposition of acetaldehyde and photoinduced hydrophilicity under the UV light illumination. The highe … More st deposition rate in this study to deposit the photocatalytic TiO_2 films in the "transition region" was 90nm/min, which was over twenty times higher than that for conventional sputter deposition processes.The WO_3 was also studied as the visible-light active photocatalyst. The WO3 films were deposited by reactive sputtering at 600 ℃ under total gas pressure of 5.0 Pa of 100 % oxygen, which performed clear photocatalytic decomposition of acetaldehyde and photo-induced hydrophilicity after visible light irradiation. The quantum yield was about 1.3 % at 440nm. The optical band gap of this film was estimated to be 2.8 eV by extrapolation of (ahv)^<1/2> plot against photon energy, wherea, h and v were absorption coefficient, Plank's constant and light frequency, respectively. Therefore, the photocatalytic reactions corresponded to inter-band transition of the electrons. These photocatalytic properties of the WO_3 films were closely related with the deposition conditions, and hence the optical band gap energy of the films. Less