ClusterDynamics · Characterising the dynamical properties of size-selected supported metal clusters

Characterising the dynamical properties of size-selected supported metal clusters

The ability of catalysts to facilitate chemical reactions and to make them selective is of immense importance for industrial production processes. A wide range of heterogeneous catalysts consists of active clusters (fewer than 100 atoms) or nanoparticles (several 100 atoms) supported on oxide surfaces. Such small particles are intrinsically metastable due to their high surface area: Clusters are often mobile on their supports which leads to sintering into larger particles, and they further exhibit internal dynamics by rearranging their atoms into different structural isomers. Moreover, clusters often exhibit special geometric structures and electronic properties, which can vary with the addition or removal of just a single atom. Clusters of different size can therefore often have vastly different catalytic properties. In order to fine-tune catalysts for maximum reactivity and selectivity, a key challenge is the fundamental understanding of particle mobility under reaction conditions. In particular, the understanding of these cluster dynamics at the atomic scale promises to allow us a more targeted design of efficient catalysts with long-term stability, however such dynamics are often not well understood. The overall objective of project ClusterDynamics was to investigate cluster stability and dynamics experimentally on increasingly complex model systems and to establish an experimental tool box for future studies. Specifically, we brought to maturity an electronic add-on module for scanning tunneling microscopes (STM) which accelerates standard instruments to video frame rates (20 fps) and beyond. Using this FastSTM method allowed us to monitor individual metal clusters on graphene and boron nitride thin films directly, giving us a picture of their dynamics in real space and real time. The dynamics of a more typical catalyst support, namely a magnetite surface, were further investigated by FastSTM. Finally, a so-called sniffer setup was implemented and tested for temperature programmed reaction (TPR) experiments. The results from this project provide fundamental knowledge within the framework addressing the societal challenges of “smart, green and integrated transport” and “climate action, environment, resource efficiency and raw materials” identified in Horizon 2020. In the long run, the new findings are expected to enable the more targeted design of efficient, highly selective and most importantly stable catalysts for applications ranging from car exhaust and exhaust gas after-treatment in industrial applications to more resource and energy efficient materials production.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз