Electron-beam irradiation induced transformation of Cu₂(OH)₃NO₃nanoflakes into nanocrystalline CuO

Abstract

The transmission electron microscope electron-beam (TEM e-beam) as a material modification tool has been demonstrated. The material modification is realised in the high-resolution TEM mode (largest condenser aperture, 150 μm, and 200 nm spot size) at a 200 keV beam energy. The Cu2(OH)3NO3 (CHN) nanoflakes used in this study were microwave solution processed that were layered single crystals and radiation sensitive. The single domain CHN flakes disintegrate into a large number of individual CuO crystallites within a 90 s span of time. The sequential bright-field, dark-field, and selected area electron diffraction modes were employed to record the evolved morphology, microstructural changes, and structural transformation that validate CHN modification. High-resolution transmission electron microscopy imaging of e-beam irradiated regions unambiguously supports the growth of CuO nanoparticles (11.8(3.2) nm in diameter). This study demonstrates e-beam irradiation induced CHN depletion, subsequent nucleation and growth of nanocrystalline CuO regions well embedded in the parent burnt porous matrix which can be useful for miniaturized sensing applications. NaBH4 induced room temperature reduction of CHN to elemental Cu and its printability on paper was also demonstrated.

Atomic Resolution Observation of the Oxidation of Niobium Oxide Nanowires: Implications for Renewable Energy Applications

“…Hence, dynamic insights into the reactions happening at the atomic scale during solid–solid transitions, which can be provided by in situ transmission electron microscopy, are crucial for our understanding of the underlying mechanisms. , Solid–solid transitions are induced by a multitude of factors, for example, temperature, pressure, strain, or changes of the atomic composition. Besides classical physical forces, irradiation by high-energy electrons can likewise cause structural transformation in materials due to local heating of the sample , or by changes of the elemental composition due to radiolysis or knock-on damage. − In this regard, the electron beam induced reduction of Nb 3 O 7 (OH) to NbO was analyzed in detail by using in situ TEM experiments . A highly intense electron beam and elevated temperatures are required for efficient sputtering of oxygen from the crystal lattice.…”

Direct observation of oxygen-vacancy formation and structural changes in Bi2WO6 nanoflakes induced by electron irradiation

“…Electron-beam irradiation is a powerful technique to fabricate or modify materials at the nanoscale [21–22]. For example, electron irradiation can induce a phase transformation from crystalline to amorphous or vice versa [23–24]; the knock-on effect of electron-beam irradiation will break chemical bonds and or knock off atoms directly from the surface of the irradiated material. Generally, it is thought that electron irradiation of materials containing heavy atoms by using a traditional transmission electron microscope (TEM) is not effective.…”

Elucidation of single atom catalysts for energy and sustainable chemical production: Synthesis, characterization and frontier science

“…24(h)). The G(CN)Cu also displayed a high turnover frequency (TOF = 13 h − 1 ) at low temperatures (<100 • C), proving that it has a strong electron-withdrawing character (withdraw electron from CF 3 -substituted benzylamine) than that of the current best performing NP catalysts in the literature (e.g., CuO nanoflakes and Cs/MnO x ) [495,496]. Through the DFT analysis and EPR measurement, a possible oxidative amine coupling mechanism for the study was proposed as shown in Fig.…”