Speaker
Description
In-situ environmental scanning transmission electron microscopy (e-STEM) provides a powerful platform for atomic-scale characterisation of materials under realistic and dynamic conditions. Such approaches are increasingly critical for advancing functional materials in energy applications, including nuclear and fusion systems, photovoltaics, batteries, and heterogeneous catalysis.
At York, we have developed open-cell environmental TEM/STEM methodologies, recently implemented on a double aberration-corrected JEOL NeoARM cold field-emission gun instrument (ARTEMIS). This system builds on our earlier environmental TEM developments and enables a broad range of in-situ experiments, combining variable accelerating voltage, controlled gas and vapour environments, 4D-STEM diffraction, and atomic-resolution EDX and EELS spectroscopy.
In this work, we highlight the capabilities of the ARTEMIS platform through three representative case studies. First, we examine redox processes in Ni/NiO and Fe nanoparticles under H₂, H₂O vapour, and O₂ environments, achieving single-atom sensitivity using HAADF-STEM under controlled temperature and gas conditions. Second, we investigate structural phase transformations in TiO₂ nanoparticles, including the formation of Magnéli phases, driven by electron-beam irradiation and influenced by environmental and thermal parameters. Third, we demonstrate in-situ, electron-beam-directed three-dimensional atomic restructuring of NiO nanoflowers via precursor-mediated β-hydroxide and nitrate–hydroxide intermediates.
These studies illustrate the unique capability of in-situ e-STEM to directly resolve dynamic processes at the atomic scale, providing insights into reaction pathways and structural evolution that are essential for the rational design of next-generation functional nanomaterials.