Tools
Bimetallic catalysis
The profitable implementation of many chemical processes requires the suppression of side reactions, while maintaining high rates in the main reaction pathway. This can be achieved by alloying two or more metals to form a surface with a new set of properties, distinct from that of its two alloying components. We seek to understand the drivers of redox properties and component segregation in the metal nanoparticles, and to correlate these to the intrinsic rates of catalytic reactions on the surface. The tools we use to probe the surface and bulk properties of the nanoparticles are, among others, in situ and operando X-ray absorption spectroscopy, FT-IR spectroscopy and electron microscopy. We apply the insights gained by these experiments in diverse reactions, ranging from biomass upgrading to automotive emissions control.
Operando X-ray absorption spectroscopy
Understanding the active site of a catalyst is very frequently the most challenging step in an investigation. To elucidate it in an unequivocal manner, we need information about the structure of the catalyst while the reaction is taking place. X-ray absorption spectroscopy is an ideal technique to achieve this. Hard X-rays can penetrate through a reactor and a reaction mixture and give the requisite information about the oxidation state and local coordination environment of the atoms in the catalyst. Our expertise lies in the design of cells to run catalytic reaction experiments at the most challenging of conditions; high pressure, high temperature liquid flow. Our work also involves the calculation of the electronic structure and local coordination environment of the atoms of interest and the correlation of these with the catalytic properties of the material.
Applications
Polymer recycling
The contamination of the world's oceans by plastic waste has resulted in the accumulation of waste material in remote communities. These communities have ordinarily poor access to recycling or other reprocessing facilities. To address this issue, in collaboration with the Rochefort group, we are investigating small-scale processes for the catalytic conversion of polymers to fuels and chemicals.
Biomass catalysis
Mitigation of climate change requires the transition to a decarbonized economy. To achieve this transition, the cost-competitive production of fuels and chemicals from biomass resources is required. In our group, we are investigating the formation of C-C bonds from platform molecules, such as ethanol, furfural and fatty acids and alcohols.