等离子合金化/热氧化复合技术制备光催化N掺杂TiO2薄膜

目的 提高316 L不锈钢表面的光催化和亲水性能.方法 通过等离子表面合金化技术在316 L不锈钢表面制备结合良好的TiN薄膜,然后对TiN薄膜进行热氧化,得到N掺杂TiO2薄膜.利用X射线衍射仪、X射线光电子能谱仪、扫描电子显微镜及紫外-可见分光光度仪对制备的N掺杂TiO2薄膜进行表征,并通过光催化实验和亲水性实验考察其光催化性能和亲水性.结果 经过空气中450℃氧化处理2 h的薄膜中存在锐钛矿晶型的TiO2,样品中的N元素取代了部分O.未掺杂TiO2和N掺杂TiO2的带隙宽度分别为3.25、3.08 eV.经热氧化处理后,薄膜表面致密,无裂纹和微孔,均匀分布着尺寸相近的微小凸起物.经可见光照射150 min后,N掺杂TiO2薄膜对亚甲基蓝溶液的最终降解率为20%.此外,N掺杂TiO2薄膜具有较高的亲水性,可见光照射下,30min内接触角降为8.5°.结论 N掺杂TiO2薄膜能有效提高316 L不锈钢表面的光催化和亲水性能.

Preparation of Photocatalytic N-doped TiO2 Films by Combined Technology of Plasma Surface Alloying / Thermal Oxidation

Objective To improve the photocatalytic and hydrophilic properties of 316L stainless steel surface. Methods N doped TiO2 thin films were obtained by thermal oxidation of titanium nitride films, which were prepared by plasma surface alloying on stainless steel substrate. The resultant thin films were characterized by X-ray diffraction ( XRD) , X-ray photoelectron spectros-copy ( XPS) , scanning electron microscopy ( SEM) , and ultra violet-visible absorption spectroscopy ( UV-Vis) methods. The pho-tocatalytic properties and hydrophilicity of N doped TiO2 thin films were studied through photocatalysis and hydrophilicity tests. Results XRD patterns showed that anatase type TiO2 existed in the thin films after thermal oxidation at 450 ℃ in air for 2 h. Ac-cording to XPS, residual N atoms partially occupied O atom sites in the TiO2 lattice. The band-gaps of TiO2 and N-doped TiO2 were 3. 25 eV and 3. 08 eV, respectively. A uniform and dense surface containing three-dimensional homogenous protuberances growth of grains was observed in SEM images of thin films after thermal oxidation. The experimental results of degradation of Methylene blue solution under visible light indicated that photocatalysis efficiency of N doped TiO2 film was better than that of the undoped film. The ultimate degradation rate of N doped TiO2 was 20% in visible irradiation for 150 min. The N doped TiO2 films showed a higher hydrophilicity and the contact angle was lowered to 8. 5° by Vis-irradiation within 30 min. Conclusion The N doped TiO2 film could effectively improve the photocatalytic and hydrophilic properties of stainless steel surface.