Bubble nucleation and migration in a lead–iron hydr(oxide) core–shell nanoparticle

Abstract

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 O 2 gas and H 2 O. 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.bubbles | nucleation | liquid cell | TEM | core-shell nanoparticle

Self-hydrogenated shell promoting photocatalytic H2 evolution on anatase TiO2

“…Anatase TiO 2 NPs were immersed in water as 0.1 mol L –1 aqueous suspension and injected into the LETEM through a homemade liquid flow holder (Fig. 1a ) 16 – 18 . An UV light fiber is introduced in between the pole pieces inside the LETEM, which releases a UV source (characteristic wavelength of 254, 297, 315, 335, 365, 404, and 425 nm) with a flux of 100 mW cm −2 at room temperature (Fig.…”

“…Here, we employ a liquid environmental transmission electron microscopy (LETEM) 16 – 18 to investigate the photocatalytic reactions occurring on the surface of anatase TiO 2 nanoparticles (NPs) immersed in water under ultraviolet (UV) illumination. The photocatalytic reactions found in this research are very different from those observed under vapor conditions in the ETEM 7 .…”

Strain-Mediated Interfacial Dynamics during Au–PbS Core–Shell Nanostructure Formation

“…Moreover, during the growth of shell on a core, strain can gradually build up around the interface. − It has been reported that the lattice strain can cause phase transformation in the Pt/Au core/shell nanocrystal, and the interfacial strain gradient can facilitate the oxidation of Fe nanoparticles confined in an iron oxide shell . We then examined the strain field at the core–shell interface by the Geometric Phase Analysis (GPA), ,− based on the high-resolution TEM images of the core–shell particles. The geometric phase obtained here is related to one-dimensional lattice displacement field u x ( r ) along the x direction, where u x ( r ) = −(1/2π) P g ( r ) g , and the g vector (220) of PbS was used for the displacement field determination.…”

Direct Observation of Early Stages of Growth of Multilayered DNA-Templated Au-Pd-Au Core-Shell Nanoparticles in Liquid Phase

“…In particular, existing reports on seed-mediated core-shell synthesis do not address the early stages of the formation and growth of the shell, critical in determining the morphology of resultant nanostructures. The in situ fluid cell electron microscopy (EM) is a powerful technique uniquely suitable for the visualization of the formation and growth of NPs in real time and correlating the changes in NP size and shape with the evolution of its crystalline structure (Liao et al, 2012; Kashyap et al, 2014; Alloyeau et al, 2015; Chen Q. et al, 2015; Chen X. et al, 2015; Gamalski et al, 2015; Hellebusch et al, 2015; Hermannsdörfer et al, 2015; Ievlev et al, 2015; Liang et al, 2015a,b; Nagao et al, 2015; Niu et al, 2015; Ross, 2015; Weiner et al, 2016). Recent reports on in situ scanning/transmission electron microscopy (S/TEM) characterization employing gas and liquid cell holder platforms highlighted advances in high-resolution imaging and precise quantification of the particle growth and mobility and pointed to the importance of controlling the electron dose (Williamson et al, 2003; Yuk et al, 2012, 2016; Welch et al, 2013, 2015; Abellan et al, 2014; Lewis et al, 2014; Liao et al, 2014; Woehl et al, 2014; Liu et al, 2015; Ngo and Yang, 2015; Park et al, 2015b,c; Patterson et al, 2015; Pohlmann et al, 2015; Stehle et al, 2015; Woehl and Prozorov, 2015).…”