Imaging a reaction taking place at the molecular level could provide direct information for understanding the catalytic reaction mechanism. We used in situ environmental transmission electron microscopy and a nanocrystalline anatase titanium dioxide (001) surface with (1 × 4) reconstruction as a catalyst, which provided highly ordered four-coordinated titanium “active rows” to realize real-time monitoring of water molecules dissociating and reacting on the catalyst surface. The twin-protrusion configuration of adsorbed water was observed. During the water–gas shift reaction, dynamic changes in these structures were visualized on these active rows at the molecular level.
Yuan, W., Zhu, B., Li, X. Y., Hansen, T. W., Ou, Y., Fang, K., Yang, H., Zhang, Z., Wagner, J. B., Gao, Y., & Wang, Y. (2020). Visualizing H2O molecules reacting at TiO2 active sites with transmission electron microscopy. Science, 367(6476), 428-430. https://doi.org/10.1126/science.aay2474