Wang Chao, Yang Jingjing, Li Taozhu, Shen Zihan, Guo Taolian, Zhang Huigang, Lu Zhenda
National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures and College of Engineering and Applied Sciences , Nanjing University , Nanjing 210093 , China.
School of Chemical and Biomolecular Engineering , Georgia Institute of Technology , Atlanta , Georgia 30332 , United States.
ACS Appl Mater Interfaces. 2020 Feb 5;12(5):5750-5758. doi: 10.1021/acsami.9b18359. Epub 2020 Jan 21.
Defects engineering of oxides plays a vital role in tuning their physicochemical and electronic properties and thereby determining their potential applications. However, the safe and controllable production of effective defects in the oxides is still challenging. Here, we report a facile one-pot solid lithiothermic reduction approach to generate graded oxygen defects in TiO nanoparticles. Various levels of lithium reduction are systematically studied, and meanwhile, a distinct phase transition from anatase TiO to cubic LiTiO is observed with the increasing lithium ratio. The structure and evolution of surface defects and bulk phase transition are investigated in detail. Afterward, we demonstrate their applications in carbon dioxide photoreduction and photothermal imaging. The slightly reduced TiO with effective oxygen defects affords a highly broadened solar spectrum absorption and yields significantly enhanced visible photocatalytic activity in CO conversion, which is further revealed by theoretical calculations. The highly reduced TiO with obvious phase transition shows enhanced solar absorption and achieves high photo-thermal-conversion efficacy, showing huge potential in photo-thermal-related applications. The lithiothermic reduction is a general and effective approach to produce defects and induce phase transition in oxides, which can be used in multiple applications.
氧化物的缺陷工程在调节其物理化学和电子性质从而决定其潜在应用方面起着至关重要的作用。然而，在氧化物中安全且可控地产生有效缺陷仍然具有挑战性。在此，我们报道了一种简便的一锅法固体锂热还原方法，用于在TiO纳米颗粒中产生分级氧缺陷。系统地研究了不同程度的锂还原，同时，随着锂比例的增加，观察到从锐钛矿TiO到立方LiTiO的明显相变。详细研究了表面缺陷的结构和演化以及体相转变。随后，我们展示了它们在二氧化碳光还原和光热成像中的应用。具有有效氧缺陷的轻度还原的TiO具有高度拓宽的太阳光谱吸收，并在CO转化中产生显著增强的可见光催化活性，理论计算进一步揭示了这一点。具有明显相变的高度还原的TiO显示出增强的太阳吸收并实现了高光热转换效率，在光热相关应用中显示出巨大潜力。锂热还原是一种在氧化物中产生缺陷和诱导相变的通用且有效的方法，可用于多种应用。
