Niu Kaiyang, Frolov Timofey, Xin Huolin L, Wang Junling, Asta Mark, Zheng Haimei
Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720;
Department of Materials Science and Engineering, University of California, Berkeley, CA 94720;
Proc Natl Acad Sci U S A. 2015 Oct 20;112(42):12928-32. doi: 10.1073/pnas.1510342112. Epub 2015 Oct 5.
Iron hydroxide is found in a wide range of contexts ranging from biominerals to steel corrosion, and it can transform to anhydrous oxide via releasing O2 gas and H2O. However, it is not well understood how gases transport through a crystal lattice. Here, we present in situ observation of the nucleation and migration of gas bubbles in iron (hydr)oxide using transmission electron microscopy. We create Pb-FeOOH model core-shell nanoparticles in a liquid cell. Under electron irradiation, iron hydroxide transforms to iron oxide, during which bubbles are generated, and they migrate through the shell to the nanoparticle surface. Geometric phase analysis of the shell lattice shows an inhomogeneous stain field at the bubbles. Our modeling suggests that the elastic interaction between the core and the bubble provides a driving force for bubble migration.
氢氧化铁存在于从生物矿物到钢铁腐蚀等广泛的环境中，并且它可以通过释放氧气和水转化为无水氧化物。然而，气体如何在晶格中传输还没有得到很好的理解。在这里，我们使用透射电子显微镜对铁（氢）氧化物中气泡的成核和迁移进行了原位观察。我们在液体池中制备了Pb-FeOOH模型核壳纳米颗粒。在电子辐照下，氢氧化铁转化为氧化铁，在此过程中产生气泡，并且它们通过壳层迁移到纳米颗粒表面。壳层晶格的几何相位分析显示气泡处存在不均匀的应变场。我们的模型表明，核与气泡之间的弹性相互作用为气泡迁移提供了驱动力。
