Currently fuels, plastics, and drugs are predominantly manufactured from oil. A transition towards renewable resources critically depends on new catalysts to convert small molecules (such as solar or biomass derived hydrogen, carbon monoxide, water and carbon dioxide) into more complex ones (such as hydrocarbons and oxygenates). Catalyst development often relies on trial and error rather than rational design, as the heterogeneity of these composite systems hampers detailed understanding of the role of each of the components.

In this project we used 3D model catalysts as a novel enabling tool to overcome this problem. Their well-defined nature allowed unprecedented precision in the variation of structural parameters (morphology, spatial distribution) of the individual components, while at the same time they mimic real catalysts closely enough to allow testing under industrially relevant conditions. Using this approach we adressed fundamental questions such as:
* What are the mechanisms (structural, electronic, chemical) by which non-metal promoters influence the functionality of copper-based catalysts?
* Which nanoalloys can be formed, how does their composition influence the surface active sites and catalytic functionality under reaction conditions?
* Which size and interface effects occur, and how can we use them to tune the activity and selectivity towards desired products?

3D model catalysts were assembled from ordered mesoporous silica and carbon support materials and consisted mainly of Cu-based promoted and bimetallic nanoparticles, although also some other bimetallic systems were explored (Co-Ni, Au-Ag, Au-Pd). The combination with high resolution imaging, active site characterization and testing under realistic conditions allowed detailed insight into the role of the different components.

Most important achievements of this project include:
* Insight into how Cu-based catalysts for the formation of CO and H₂ into fuels and chemical building blocks such as methanol can have a longer lifetime and work more effectively, and how this is influenced by interface effects (with the support), the sieze of the Cu particles, and small amounts of additive ("promoters")
* Concrete information on the impact of switching to CO₂ as feed for building chemicals and fuels, and how the catalyst can be adjusted to account for that
* First results on copper-based catalysts for electrochemical CO₂ reduction, and the importance of a second component (much prominently CuS_x and Cu-ZnO_x
* fundamental understanding of the behaviour of nano-alloys, also under reaction conditions, and how the atoms of tow different metals will redistribute, and how that affect the efficiency of the catalysts.

• dr. K. (Kai) Han
• dr. P. (Peter) Ngene
• dr. R. (Remco) Dalebout