LabAdviser/Technology Research/High-resolution TEM cat-nano-surf

From LabAdviser

High-resolution transmission electron microscopy of catalytic nanoparticle surfaces

  • Project type: Ph.D project
  • Project responsible: William Bang Lomholdt
  • Supervisors: Thomas Willum Hansen, Jakob Schiøtz
  • Partners involved: DTU Physics


Project description

High resolution (HR) electron microscopy (EM) is a well-developed method to investigate sub-micrometer to sub-nanometer (especially atomic-scale) features on speci-mens to investigate. In examples for the field of energy conversion and micro- and nanoelectronics, it has become a central aspect of designing modern materials. For the field of catalysts, it is of high importance to understand structural behavior using atomic-scale (sub-Ångstrøm) microscopy, of which can be achieved with transmission elec-tron microscopy (TEM) of thin (up to 100 nm thick) samples of interests. In the presence of gases and elevated temperature, TEM can investigate catalysts in-situ to obtain the structural be-havior during the reaction, called environmental TEM (ETEM). Outcome of such investigations are a huge amount of data, which is time consuming to investigate, along it is operator biased. Machine-learning, especially deep learning, algo-rithms can be used to investigate structure changes at low S/N ratio and thus provide automatic analysis. These algo-rithms are applied in the microscope surface and devel-oped by theoretical researchers at DTU Physics. In this particular project, surface structures will be investi-gated under varying conditions using ETEM. As the investigations and thus the algorithm performances depends on these terms, first the effects of electron dose, dose rate, temperature etc. will be mapped. Quantitative and qualitative investigations of 3D structures, including particle and surface diffusions, morphology etc. are fur-thermore investigated with the results of the first task in mind. The investigations will be supported by scanning (T)EM and electron tomography, some of these at external facilities.

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