In-Situ-Reduced Synthesis of Ti3+ Self-Doped TiO2/g-C3N4 Heterojunctions with High Photocatalytic Performance under LED Light Irradiation
In-Situ-Reduced Synthesis of Ti3+ Self-Doped TiO2/g-C3N4 Heterojunctions with High Photocatalytic Performance under LED Light Irradiation
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DOI：
10.1021/am508505n
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发表时间：
2015-05-06
影响因子：
9.5
通讯作者：
Lu, Jun
中科院分区：
文献类型：
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作者：
Li, Kai;Gao, Shanmin;Lu, Jun
以H_2Ti3O_7和三聚氰胺为原料，采用简单的一步焙烧法制备了Ti3+自掺杂的Ti3+/g-C3N4异质结。用X射线衍射仪、透射电子显微镜、高分辨电子显微镜、X射线光电子能谱、电子自旋共振、紫外-可见漫反射光谱等技术对样品的结构、结晶度、形貌和化学状态进行了表征。与纯的TiO2和g-C3N4相比，制备的Ti3+自掺杂的Ti3+/g-C3N4异质结的吸收峰向长波方向移动。以30W可见光二极管为光源，研究了异质结对亚甲基蓝的光催化活性。结果表明，制备的Ti3+自掺杂Ti3+/g-C3N4异质结的可见光催化活性优于纯的TiO2光催化剂和g-C3N4异质结。并对其光催化机理进行了探讨。光致发光(PL)谱证实了光生电子空穴在所制备的异质结中的强烈分离效率。22.3wt%Ti3+自掺杂二氧化钛/g-C3N4异质结的去除速率常数达到0.038 m in(-1)，分别是纯二氧化钛和g-C3N4的26.76倍和7.6倍。二氧化钛纳米粒子与g-C3N4纳米片界面之间建立的异质结以及Ti3+的引入使得Ti3+的快速电子转移速率和光生电子-空穴对的分离效率提高，从而改善了Ti3+自掺杂的Ti3+/g-C3N4异质结的光催化性能。
A simple one-step calcination route was used to prepare Ti3+ self-doped TiO2/g-C3N4 heterojunctions by mixture of H2Ti3O7 and melamine. X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), electron spin resonance (ESR) spectroscopy, and UV-Vis diffuse reflectance spectroscopy (UV-vis DRS) technologies were used to characterize the structure, crystallinity, morphology, and chemical state of the as-prepared samples. The absorption of the prepared Ti3+ self-doped TiO2/g-C3N4 heterojunctions shifted to a longer wavelength region in comparison with pristine TiO2 and g-C3N4. The photocatalytic activities of the heterojunctions were studied by degrading methylene blue under a 30 W visible-light-emitting diode irradiation source. The visible-light photocatalytic activities enhanced by the prepared Ti3+ self-doped TiO2/g-C3N4 heterojunctions were observed and proved to be better than that of pure TiO2 and g-C3N4. The photocatalysis mechanism was investigated and discussed. The intensive separation efficiency of photogenerated electron-hole in the prepared heterojunction was confirmed by photoluminescence (PL) spectra. The removal rate constant reached 0.038 min(-1) for the 22.3 wt % Ti3+ self-doped TiO2/g-C3N4 heterojunction, which was 26.76 and 7.6 times higher than that of pure TiO2 and g-C3N4, respectively. The established heterojunction between the interfaces of TiO2 nanoparticles and g-C3N4 nanosheets as well as introduced Ti3+ led to the rapid electron transfer rate and improved photoinduced electron-hole pair's separation efficiency, resulting in the improved photocatalytic performance of the Ti3+ self-doped TiO2/g-C3N4 heterojunctions.