Carbon-supported nickel catalysts for the hydrogenation of carbon dioxide

This thesis describes the preparation, characterization and catalytic performance of nickel-based catalysts carbon dioxide hydrogenation. This reaction is of interest in the Power-to-Gas process, in which carbon dioxide and hydrogen are converted to methane, as a replacement for fossil natural gas. By making the required hydrogen with electricity from renewable energy sources, electricity can be stored in chemical bonds. Carbon dioxide conversion needs a lot of energy and can be accelerated with the use of a catalyst. The goal of the research described in this thesis was to find structure-performance relations of supported nickel catalysts for carbon dioxide hydrogenation. In order to do this, the effect of nickel nanoparticle size, support and promoters were disentangled and studied separately. The conversion and selectivity of carbon-supported nickel catalysts can be improved by changing the size of the nickel nanoparticles and by the addition of certain metal oxide promoters. Adjustments in the support material increase the stability of the catalyst, mainly by preventing the nanoparticles from moving and growing. In addition, experimental protocols were developed to visualize the catalysts under gas atmosphere in a closed nanoreactor in an transmission electron microscope. This novel technique was used to gain more insight into the growth of the nickel nanoparticles and hence their stability under reaction conditions. The fundamental knowledge obtained in this research can contribute to the further development of efficient catalysts for carbon dioxide conversion.