Construction of semiconductor heterojunctions is an efficient strategy to improve photo-induced charges separation and thus enhance photocatalytic activities. Herein, g-C3N4/TiO2 heterostructures were prepared via a facile thermal procedure, with TiO2 nanorods as matrix and g-C3N4 as visible-light sensitizer. Heterojunctions formed while precursors cyanamide polymerized to g-C3N4 and protonated titanate nanotube (H-TNTs) dehydrated and shrinked to TiO2 nanorods. Notably, confined polymerization of g-C3N4 occurred at both external surface and internal space of H-TNTs with the assistant of vacuum treatment, while NH3 released from cyanamide decomposition yielded abundant oxygen vacancies (VO) in TiO2 nanorods. Compared with pristine TiO2 nanorods, the heterostructured g-C3N4/TiO2 nanorods possess 1.7 times more active in photocatalytic removal of organic dye Orange II. A mechanism was proposed for heterostructured g-C3N4/TiO2 nanorods, being attributed to synergistic increasing light harvesting by VO and charges separation by heterojunctions.

中文翻译：

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具有富氧空位的纳米管约束诱导的 g-C3N4/TiO2 纳米棒增强光催化水净化

半导体异质结的构建是改善光诱导电荷分离从而增强光催化活性的有效策略。在此，g-C3N4/TiO2 异质结构是通过简单的热程序制备的，以 TiO2 纳米棒为基质，g-C3N4 作为可见光敏化剂。当前体氰胺聚合成 g-C3N4 和质子化钛酸纳米管 (H-TNTs) 脱水并收缩成 TiO2 纳米棒时，形成了异质结。值得注意的是，在真空处理的辅助下，g-C3N4 在 H-TNTs 的外表面和内部空间发生了受限聚合，而氰胺分解释放的 NH3 在 TiO2 纳米棒中产生了丰富的氧空位（VO）。与原始的 TiO2 纳米棒相比，异质结构的 g-C3N4/TiO2 纳米棒具有 1. 光催化去除有机染料 Orange II 的活性提高 7 倍。提出了一种用于异质结构 g-C3N4/TiO2 纳米棒的机制，这归因于 VO 的协同增加光收集和异质结的电荷分离。