Abstract:

Carbon doped ZnO thin films with high catalytic activity were prepared on glass surface by magnetron sputtering. The prepared thin films were characterized by X-ray diffractometer, high power transmission electron microscopy and X-ray photoelectron spectroscopy. The photocatalytic properties of the films were tested for the visible-light driven conversion of nitrogen to ammonia. The results show that there are carbon quantum dots in the films with a size of 4nm and an interplanar spacing of 0.21nm that allows the thin films to absorb visible light. At the same time, the carbon atoms in the ZnO lattice may increase the conduction band edge position of the films, so that the reductive potential of the excited electrons is enhanced. When the amount of carbon doping was 1.03%, the ammonia yield was 5.15×10^-4mol/(h·cm²). Sphere segment shaped pits with an opening size of 0.5—2μm and a depth of 100—500nm were made on the glass surface using a reverse micelle solution etching technology. The ammonia yields of the films on the etched glass was about 1.4 times higher than that on the plane glass. Meanwhile, the critical load values for the films on the etched glass were about 2 times higher than those for the ones on the unetched glass. Following that, the photocatalytic mechanism was discussed based on the band structure diagram of the carbon doped ZnO films.

Key words: film, magnetron sputtering, photochemistry, ammonia

摘要：

采用磁控溅射双靶共溅射方法，在玻璃表面成功制备了高催化活性的碳掺杂ZnO薄膜。通过X射线衍射仪、高倍透射电镜、X射线光电子能谱仪等表征了碳掺杂ZnO薄膜，并在可见光催化氮合成氨实验中评价了薄膜的催化剂性能。结果表明碳掺杂的ZnO薄膜中存在碳量子点，尺寸为4nm，晶面间距0.21nm，薄膜可以吸收可见光。同时ZnO晶格中的碳提高了ZnO导带的位置，增强了激发电子的还原能力。当碳掺杂量为1.03%时，氨氮产量为5.15×10^–4mol/(h·cm²)。利用反胶束蚀刻法又成功地在玻璃表面蚀刻出了微米坑，坑口径为0.5～2μm，坑深为100～500nm。与平面玻璃表面上的薄膜比较，在光催化氮合成氨实验中微米坑玻璃表面上薄膜的氨氮产量提高了约1.4倍，膜基结合力提高了2倍多。结合薄膜的能带结构图讨论了碳掺杂ZnO薄膜的光催化机理。

关键词: 膜, 磁控溅射, 光化学, 氨