Martin Muhler: Selective Catalytic Oxidation over Cobalt-based Spinel and Perovskite Nanoparticles

Martin Muhler (Ruhr University Bochum): Selective Catalytic Oxidation over Cobalt-based Spinel and Perovskite Nanoparticles

TACO Colloquium on March 21, 2022.

Abstract: The selective oxidation of organic molecules to value-added products is one of the major challenges in chemical industry. At high temperatures in the gas phase the Mars-van Krevelen mechanism dominates in the few established large-scale processes such as the synthesis of acrolein and acrylic acid, maleic anhydride or phthalic anhydride based on vanadia and molybdena catalysts. In contrast, selective oxidation in the liquid phase occurs at much lower temperatures over metals and oxides without involving changes of the bulk structure. In my talk I will first present the selective oxidation of 2-propanol over Co3O4 nanoparticles in the gas phase and in the liquid phase covering the involved mechanism and the active sites, structure sensitivity, and the role of iron substitution leading to the size of the catalytically active ensemble. Then, I will address the selective oxidation of more complex molecules such as cyclohexene over substituted LaCoO3 pointing out the role of radicals and cinnamyl alcohol using tert-butyl hydroperoxide as oxidant. Non-catalytic processes have to be taken into account properly, and the used solvent may participate in the catalytic cycle. All results originate from the fruitful collaboration within the TRR/CRC 247 comprising the research areas synthesis, analysis and catalysis. Selected samples will illustrate the various synthetic routes to oxide nanoparticles including post-processing by laser methods, advanced operando experiments, and support from theory.