These limitations are of distinct prominence in the study of electron beam-sensitive materials, such as metallic hydroxides and oxides 19, 20, 21. The electron beam has the ability to structurally and chemically change these types of materials during TEM characterization. However, an established drawback of TEM is electron beam-induced sample damage caused by complex interaction mechanisms such as radiolysis, atomic displacement (so-called ‘knock-on’) and Joule heating 16, 17, 18. A schematic of the TEM and EELS imaging principles along with a crystallographic representation of a typical LDH structure is displayed in Fig. Thus revealing electronic structure and bonding information at very high spatial resolutions down to single-atom levels 15. This entails the probing of core and valence level excitations caused by the incident beam, where electrons are collected based on their energy after interacting with the specimen. Simultaneously, a further wealth of knowledge can be provided using complementary techniques such as electron energy loss spectroscopy (EELS). In this regard, transmission electron microscopy (TEM)/scanning TEM (STEM) can reveal a wide range of physical phenomena at high spatial and energy resolutions. This combination indeed justifies a necessity to provide a full understanding of these materials from all aspects of nanotechnology 13, 14. This is also partnered with a fascination of how these materials attain their associated structures and properties. Recently, researchers have progressed the development and application of various LDH materials down to the atomic scale 11, 12. Such versatility is largely owed to their inherent physical and chemical features including surface areas, controllable synthesis methods, compositional tunability and favourable interactions to form composites 9, 10. In particular, the latest studies involving nickel and iron LDHs have placed these materials at the frontier of oxygen evolution reaction research 7, 8. The scientific interest in transition metal-based layered double hydroxides (LDH) has led to an exhibition of applications across nanotechnology in areas such as batteries, water splitting and nanomedicine 1, 2, 3, 4, 5, 6. An emphasis on the dehydroxylation processes and anionic mass-loss facilitation is discussed. Moreover, in situ specimen cooling revealed the retention of interlayer nitrates. At lower acceleration voltages, an increased dehydration rate of the LDH cationic layers is observed during irradiaton. It was found that TEM conditions profoundly affected the decomposition behaviours. In parallel, nitrogen K edge attenuation demonstrated interlayer mass-losses. During 300 kV irradiation, a pre-peak evolution in the oxygen K edge highlighted a transition to metal oxide species. In addition, a compositional change was established by electron energy loss spectroscopy (EELS). The generation of pores and crystallographic breakdown of the LDH routinely occurred. The Ni–Fe LDHs were susceptible to significant structural decompositions during electron irradiation. The initial structure possessed a flat hexagonal morphology made up of crystalline domains with a well-defined hexagonal crystal structure. Electron irradiation of Ni–Fe layered double hydroxides (LDHs) was investigated in the transmission electron microscope (TEM).
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