Dark titania (TiO_x) have been widely used for solar energy harvesting and conversion applications due to its excellent light absorbing performance throughout the ultraviolet to near infrared wavelength band, low cost, and non-toxic nature. However, the synthesis methods of dark TiO_x are usually complicated and time-consuming. Here we report a facile and rapid method to fabricate dark amorphous TiO_x (am-TiO_x) hollow nanotube arrays on nanoporous anodic alumina oxide (AAO) templates using atomic layer deposition. Systematic investigation was performed to demonstrate that Ti³⁺ and O^- species in the am-TiO_x ultra-thin films, as well as the spatial distribution of these am-TiO_x ultra-thin films on the vertical side walls of AAO templates are two major mechanisms of the black color. Importantly, the film deposition took ~18 min only to produce the optimized ~4‐nm‐thick am-TiO_x film. Representative applications were demonstrated using photocatalytic reduction of silver nitrate and photothermal solar vapor generation, revealing the potential of these ultra-thin dark am-TiO_x/AAO structures for full spectrum solar energy harvesting and conversion.

暗二氧化钛（TiO _x）由于其在整个紫外线至近红外波段内均具有出色的吸光性能，低成本和无毒性质，因此已广泛用于太阳能的收集和转换应用。然而，深色TiO _x的合成方法通常是复杂且费时的。在这里，我们报告了一种简便而快速的方法，该方法使用原子层沉积技术在纳米多孔阳极氧化铝（AAO）模板上制造深色无定形TiO _x（am-TiO _x）空心纳米管阵列。进行系统的调查证明，钛³⁺和O ^-种在AM-TIO _X超薄膜以及这些am-TiO _x超薄膜在AAO模板的垂直侧壁上的空间分布是黑色的两个主要机理。重要的是，膜沉积仅需约18分钟即可生产出优化的约4nm厚的am-TiO _x膜。使用光催化还原硝酸银和产生光热太阳能蒸气演示了代表性应用，揭示了这些超薄深色am-TiO _x / AAO结构在全光谱太阳能收集和转换中的潜力。