Han Hyeuk Jin, Lee Gyu Rac, Xie Yujun, Jang Hanhwi, Hynek David J, Cho Eugene N, Kim Ye Ji, Jung Yeon Sik, Cha Judy J
Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT 06511, USA.
Energy Sciences Institute, Yale West Campus, West Haven, CT 06516, USA.
Sci Adv. 2021 Oct 8;7(41):eabh2012. doi: 10.1126/sciadv.abh2012.
Nanograined metal oxides are requisite for diverse applications that use large surface area, such as gas sensors and catalysts. However, nanoscale grains are thermodynamically unstable and tend to coarsen at elevated temperatures. Here, we report effective grain growth suppression in metal oxide nanoribbons annealed at high temperature (900°C) by tuning the metal-to-oxygen ratio and confining the nanoribbons. Despite the high annealing temperatures, the average grain size was maintained at ~6 nm, which also retained their structural integrity. We observe that excess oxygen in amorphous tin oxide nanoribbons prevents merging of small grains during crystallization, leading to suppressed grain growth. As an exemplary application, we demonstrate a gas sensor using grain growth–suppressed tin oxide nanoribbons, which exhibited both high sensitivity and unusual long-term operation stability. Our findings provide a previously unknown pathway to simultaneously achieve high performance and excellent thermal stability in nanograined metal oxide nanostructures.
纳米晶金属氧化物对于诸如气体传感器和催化剂等需要大表面积的各种应用来说是必不可少的。然而，纳米级晶粒在热力学上是不稳定的，并且在高温下容易粗化。在此，我们报告了通过调整金属与氧的比例并限制纳米带，在高温（900°C）退火的金属氧化物纳米带中有效抑制晶粒生长。尽管退火温度很高，但平均晶粒尺寸保持在约6纳米，并且还保留了它们的结构完整性。我们观察到非晶态氧化锡纳米带中的过量氧可防止小晶粒在结晶过程中合并，从而抑制晶粒生长。作为一个示例性应用，我们展示了一种使用晶粒生长抑制的氧化锡纳米带的气体传感器，该传感器表现出高灵敏度和异常的长期运行稳定性。我们的发现为在纳米晶金属氧化物纳米结构中同时实现高性能和优异的热稳定性提供了一条前所未知的途径。
