高效TiO2基光催化材料的开发一直是催化领域的研究热点，主要的策略是如何有效地分离光生载流子.制备多晶相的TiO2材料可引入异质/相结结构使电子与空穴朝不同方向移动，从而避免电子与空穴复合；另外，在TiO2中掺杂其他金属或非金属也可以有效地降低电子与空穴的复合率，掺杂的元素作为电子捕获阱俘获光生电子，以实现电子空穴的有效分离.近些年，作为一种全新的掺杂剂，氧空穴可以有效改善TiO2的光催化活性，所制TiO2具有可见光的全光谱吸收能力，因此该类TiO2呈现出黑色.通过上述方法均可以制备出高活性TiO2基光催化材料，如果能够将这些方法耦合一起，则可能制备出活性更高的光催化剂.因此，本文将异相结结构和空穴掺杂耦合起来，用多孔钛酸盐衍生物在H2中高温焙烧制得一种全新的黑色TiO2(B)/锐钛矿双晶TiO2–x纳米纤维.不同于其他TiO2基光催化材料，该样品仅由Ti和O元素组成，通过Ti和O元素的组合，形成了双晶结构和空穴掺杂两种特殊的结构，借助场发射(FESEM)、拉曼光谱(Raman)、氮气物理吸脱附、X射线光电子能谱(XPS)、热重(TG)、紫外可见漫反射光谱(UV-Vis)和荧光光谱(PL)等表征分析了样品的结构及其光催化性能间构效关系. FESEM结果显示，黑色TiO2(B)/锐钛矿双晶TiO2–x为长1–5mm、宽0.2mm的纤维结构， Raman结果表明，锐钛矿相在特征波段(140 cm–1左右)和TiO2(B)的特征波段(220–260 cm–1)均发生蓝移，说明该两相中均存在氧空穴；该样表面未检测到Ti3+，因此氧空穴可能分散在TiO2(B)和锐钛矿相的体相中.根据黑色TiO2(B)/锐钛矿双晶TiO2–x和白色TiO2(B)/锐钛矿双晶TiO2的失重差，估算出前者的O/Ti原子比为1.97.光催化降解甲基橙实验结果显示，黑色TiO2(B)/锐钛矿双晶TiO2–x的光催化活性是白色双晶TiO2的4.2倍，锐钛矿TiO2的10.5倍，且连续反应10次后未出现失活现象，显示出了良好的光催化稳定性.前期，我们已经证明了白色TiO2(B)/锐钛矿双晶TiO2由于具有TiO2(B)和锐钛矿的异相结结构，致使其电子空穴有效地分离，从而表现出优异的光催化活性；本文的PL结果显示，由于氧空穴的引入，异相结与氧空穴两者共同作用，进一步促进了黑色TiO2(B)/锐钛矿双晶TiO2–x电子与空穴的有效分离，因此黑色TiO2(B)/锐钛矿双晶TiO2–x表现出高的光催化活性.由于其特殊的结构，黑色TiO2(B)/锐钛矿双晶TiO2–x纳米纤维将在环境与能源领域表现出良好的应用前景.
Black TiO2(B)/anatase bicrystalline TiO2–x nanofibers were synthesized from a porous titanate de‐rivative by calcination in H2, and were characterized using field‐emission scanning electron micros‐copy, Raman spectroscopy, N2 adsorption‐desorption analysis, X‐ray photoelectron spectroscopy, thermogravimetric analysis, ultraviolet‐visible diffuse reflection spectroscopy and photolumines‐cence measurements. Characterization results showed that no Ti3+was present on the surface of black bicrystalline TiO2–x and oxygen vacancies were distributed in the bulk of both TiO2(B) and anatase phases. The O/Ti atom stoichiometric ratio of black bicrystalline TiO2–x was estimated to be 1.97 from the difference of mass loss between black bicrystalline TiO2–x and white bicrystalline TiO2 without oxygen vacancies. The photocatalytic activity of black bicrystalline TiO2–x was 4.2 times higher than that of white bicrystalline TiO2 and 10.5 times higher than that of anatase TiO2. The high photocatalytic activity of black bicrystalline TiO2–x was attributed to its effective separation of elec‐trons and holes, which may be related to the effects of both bicrystalline structure and oxygen va‐cancies. Black bicrystalline TiO2–x also exhibited good photocatalytic activity after recycling ten times. The black bicrystalline TiO2–x nanofibers show potential for use in environmental and energy applications.
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