A powerful and versatile tool

Transmission electron microscopy (TEM) provides powerful and versatile tools for directly probing the structural and chemical state of heterogeneous catalysts ranging from the μm-level down to the atomic-scale. This capablity provides unique 3D visualisations of complex nanostructured catalysts, which are exceedingly in the understanding of their catalytic properties.

The environmental transmission electron microscope

Over recent years, Topsoe has been involved in the development and application of a novel high-resolution transmission electron microscope with in situ capabilities - a so-called environmental TEM (ETEM). This instrument has given us a more detailed understanding of several catalyst phenomena by providing direct insight into the dynamic behaviour of catalysts in their functioning state.

In 2008, Topsoe installed its second-generation ETEM facility including an aberration-corrector to boost visibility and resolution of single-atomic structures at catalyst surfaces.

Case

Insight into the catalytic growth of carbon nanofibres and whiskers was obtained by directly monitoring the process in situ. In the experiment a nickel nanocluster catalyst was exposed to a gas mixture of methane and hydrogen at elevated temperatures. The movies revealed insight into the surface dynamic processes and through interplay with DFT demonstrated that mono-atomic step sites act as the catalytic active growth centers for the graphene layers.

Watch the ETEM film clips recorded in our laboratory