PEALD原位掺杂制备纳米TiO2-xNx光催化剂

采用等离子体增强型原子层沉积(PEALD)系统原位掺杂制备了TiO_2-xN_x光催化剂。利用光电子能谱(XPS)、高分辨率透射电镜(HRTEM)、光致发光(PL)光谱和紫外–可见光(UV-Vis)光谱对催化剂进行了表征, 并研究了TiO_2-xN_x纳米薄膜在可见光照射下水接触角的变化和催化降解亚甲基橙(MO)溶液的性能。结果表明, 等离子体功率变化可以改变掺入氮原子的结构, 在功率为50 W时主要形成替换式氮原子, 含量约为1.22at%, 晶体为锐钛矿(101)型。结构无明显缺陷, 且掺杂后TiO_2-xN_x薄膜光生电子–空穴对复合率低, 有利于光催化效率的提高。该方法解决了传统ALD工艺制备TiO_2-xN_x光催化剂时容易形成氧空位的问题, 实现了TiO2-xNx纳米材料的可见光(λ<800 nm)吸收和可见光光催化性能。

Preparation of Nano-scaledTiO2-xNx Photocatalyst by PEALD in-situ Doping

TiO_2-xN_x photocatalyst was deposited by plasma-enhanced atomic layer deposition (PEALD) system using in-situ doping method. X-ray photoelectron spectroscope (XPS), high-resolution transmission electron microscope (HRTEM), photoluminescence (PL), UV-Vis spectra were used to characterize the photocatalyst, and the variation of water contact angles and photocatalytic decomposition property ofTiO_2-xN_x nano films to methylene orange (MO) solution under visible light were investigated. The results show that the incorporated nitrogen structures could be adjusted by plasma powers, and substitutional atoms are mainly formed in the TiO₂ films deposited at the plasma power of 50 W, which is about ~1.22at%. The crystal type is anatase (101). No defect is observed in theTiO_2-xN_x films, and the recombination rate of the photo-generated electron-hole pairs is lower, which is conducive to the improvement of the photocatalytic efficiency. This method solves the problem of the formation of oxygen vacancies in the classic ALD growth process to prepare TiO2-xNx photocatalysts and theTiO_2-xN_x nano films realize visible absorption and visible light photocatalytic activity under visible light irradiation (λ<800 nm).