Congratulations to Dr. Iris ten Have for an Excellent PhD Defense. Iris has successfully defended her PhD thesis, supervised by Prof. Bert Weckhuysen and Dr. Florian Meirer.

In her PhD thesis, Iris described surface-sensitive spectroscopy as a promising analytical tool for a better understanding reaction and deactivation mechanisms in heterogeneous catalysis. She set the stage for investigating the cobalt-catalyzed CO and CO2 hydrogenation reactions. A two-pronged approach was formulated: firstly, they aimed to provide new or improved insights into the catalytically active phase. Secondly, they targeted uncovering the reaction mechanisms during the formation of (un)desired reaction products. In her PhD research, Iris used infrared and Raman spectroscopy to decipher the reaction mechanisms involved in hydrocarbon product formation during the CO hydrogenation with cobalt-titania catalysts.  They also refute the general consensus that metallic cobalt is the only active phase in heterogeneous catalysis, as cobalt oxide nanoparticles on titania performed better in terms of long-chain hydrocarbon yield than the metallic cobalt variant. While metallic cobalt dissociated CO2 into CO directly, cobalt oxide required hydrogen atoms to split the C-O bonds. They explored potassium promoter effects in the CO and CO2 hydrogenation reactions with cobalt-titania catalysts. The addition of potassium to the cobalt-titania catalyst appeared interesting for renewable energy applications that aim to convert CO2 into long-chain hydrocarbons. Potassium made the cobalt surface slightly positively charged and enabled the conversion of CO2 into the more reactive CO molecule via the reverse water-gas shift reaction. Besides, the amount of hydrogen on the catalyst surface diminished upon adding potassium.

Iris’s PhD thesis is available to read here.