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3D Model Catalysts to explore new routes to sustainable fuels

Periodic Reporting for period 3 - 3MC (3D Model Catalysts to explore new routes to sustainable fuels)

Reporting period: 2018-09-01 to 2020-02-29

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 use 3D model catalysts as a novel enabling tool to overcome this problem. Their well-defined nature allows 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 fundamental questions are addressed, 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?
Our 3D model catalysts are assembled from ordered mesoporous silica and carbon support materials and further consist of Cu-based promoted and bimetallic nanoparticles. The combination with high resolution imaging, active site characterization and testing under realistic conditions allows detailed insight into the role of the different components; critical for the rational design of novel catalysts for more sustainable production of chemicals and fuels from renewable resources.
A first PhD student (PhD1), Lisette Pompe, has been active on the project sinds September 2015, working on the project of Promoters for Cu based catalysts. Lisette started by preparing supported Cu nanoparticles on different supports, and investigating how most stable catalysts can be made (comparing for instance precipitation by impregnation routes) which yielded results that will probably lead to a publication on their own. Experiments on conversion of synthesis gas to methanol have been performed, focussing first on varying the Cu particle size, establishing procedures for producing stable support Cu catalysts and interestingly discovered how the particle size can be tuned by adapting the reduction conditions (varying reducing agent, concentration, ramp rate). She then continued by investigating how teh preparation method influenced the stability of the catalyst exploring several types of model catalysts. The well defined nature of these model catalysts allowed to unravel the nature of Cu particle growth during catalysis. Lisette has presented her results at various international conferences such as the North American Catalysis Meeting in Denver in June 2017, and is now busy finishing off the papers and writing her thesis (expected PhD defence date end 2018). A first paper on model catalyst preparation has been submitted to J. Catal. a second and third paper on particle size distribution and support effects on catalyst stability are close to submission. A third paper on Cu on carbon catalysts is envisioned for later in 2018.

Remco Dalebout (PhD2) has started (October 2016) to work on pore-confined bimetallic nanoparticles. He has started synthesis of Cu-Co bimetallic catalysts. He has also contributed to the technical specifications and discussions about specific chemistry/analysis that allowed us to order the equipment (in November 2016) to allow us to run experiments to convert synthesis gas to higher alcohols, including the design of adequate analytics. This equipment has been delivered at the end of 2017 and we have finished commissioning. First catalysis experiments are running.

Marisol Tapia Rosales has started 1 October 2016 working on the project using Cu-based catalysts for the direct CO2 reduction/Solar Fuels (PhD3). She has started preparing the first electrodes consisting of copper nanoparticles on highly conductive carbon supports. A challenge in the coming month will be to develop a receipe that allows mechanically robust and porous electrodes, without adding binders that passivate the copper electrocatalysts. Furthermore a rotating disk electrode (RDE) set up was ordered, that allows to unravel the effects of mass transport and fundamental kinetics.

Lastly Peter Ngene (PD1) has recently (1 January 2017) started working on the project, while Jan Willem de Rijk has been the supporting technician, allowing the high pressure methanol synthesis experiments (PhD1), being responsible for the technical implementation of the acquisition of the equipment (technical specifications, contact with all possible suppliers, negatiations) to investigate synthesis gas to higher alcohols (PhD2) as well as assisting with the start of dedicated Solar Fuels set-up able to handle the conversion of CO2 (PhD3). As this requires at the start really full time technical support, but it is expected that later on the PhD students and postdocs will be able to maintain and run the equipment themselves, we decided to shift the budget for the technician from 5 years 0.6 FTE to 3 years 1.0 FTE.
We expect new insight intothe role of the different components (particle size, composition, support and promoters) in supported heterogeneous catalysts; critical for the rational design of novel catalysts for more sustainable production of chemicals and fuels from renewable resources.