Zhou Yufan, Li Ming, Zhang Tao, Chen Ying, Li Xinyu, Jia Hao, Xu Pengcheng, Li Xinxin
State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai200050, People's Republic of China.
University of Chinese Academy of Sciences, Beijing100049, People's Republic of China.
Nano Lett. 2023 Mar 22;23(6):2412-2420. doi: 10.1021/acs.nanolett.2c04756. Epub 2023 Jan 31.
Calcination plays a vital role during material preparation. However, the calcination conditions have often been determined empirically or have been based on trial and error. Herein we present a cooperative characterization approach to optimize calcination conditions by gas-cell TEM in collaboration with microcantilever-based thermogravimetric analysis (cantilever-TGA) techniques. The morphological evolution of precursors under atmospheric conditions is observed with TEM, and the right calcination temperature is provided by cantilever-TGA. The proposed approach successfully optimizes the calcination conditions of fragile MnO nanowire precursors with multiple valence products. The cantilever-TGA shows that a calcination temperature above 560 °C is required to transform the MnO precursor to MnO under an N atmosphere, but the TEM indicates that the nanowire structure is destroyed within only 30 min under calcination conditions. Our method further suggests that heating the precursor at 400 °C using an H-containing atmosphere can produce MnO nanowires with good electrical properties.
煅烧在材料制备过程中起着至关重要的作用。然而，煅烧条件通常是凭经验确定的，或者是基于反复试验确定的。在此，我们提出一种协同表征方法，通过气室透射电子显微镜（TEM）与基于微悬臂梁的热重分析（悬臂梁热重分析，cantilever-TGA）技术协作来优化煅烧条件。利用TEM观察前驱体在大气条件下的形态演变，并通过悬臂梁热重分析提供合适的煅烧温度。所提出的方法成功地优化了具有多种价态产物的易碎MnO纳米线前驱体的煅烧条件。悬臂梁热重分析表明，在N气氛下，需要高于560℃的煅烧温度才能将MnO前驱体转化为MnO，但TEM表明在煅烧条件下，纳米线结构仅在30分钟内就被破坏。我们的方法进一步表明，在含H气氛中于400℃加热前驱体可以制备出具有良好电学性能的MnO纳米线。
